1Thursday, 3rd June, 1999
2 (Open session)
3 (The accused entered court)
4 (The witness entered court)
5 --- Upon commencing at 9.00 a.m.
6 THE REGISTRAR: Case IT-95-16-T, the
7 Prosecutor versus Zoran Kupreskic, Mirjan Kupreskic,
8 Vlatko Kupreskic, Drago Josipovic, Dragan Papic, and
9 Vladimir Santic.
10 JUDGE CASSESE: Thank you. Good morning.
11 Good morning, Professor Wagenaar. I would
12 like to ask you to make the solemn declaration,
14 THE WITNESS: I solemnly declare that I will
15 speak the truth, the whole truth, and nothing but the
17 JUDGE CASSESE: Thank you so much. You may
18 be seated.
19 Counsel Par?
20 MR. PAR: Good morning, Your Honours.
21 WITNESS: WILLEM A. WAGENAAR
22 Examined by Mr. Par:
23 Q. Good morning, Professor Wagenaar. Do you
24 hear me well, Professor?
25 To begin with, Professor, I should like to
1ask you, for the record, to give us your full name,
3 A. My name is Willem Albert Wagenaar.
4 Q. Thank you. Would you be kind enough to
5 convey to the Court some information about your
6 professional career, the posts you have held in the
7 past and that you are holding at present?
8 A. I am an experimental psychologist, and
9 experimental psychology deals with the general
10 psychological faculties that humans have, like
11 perception, visual perception, auditory perception,
12 memory, and general capabilities like that.
13 I was first trained at Utrecht University and
14 defended my dissertation at Leiden University. From
15 there on, I worked for 20 years in the Institute for
16 Perception, TNO, which is a separate research institute
17 in the Netherlands that deals with mostly questions of
18 perception, and face perception is one of the topics
19 that I addressed there.
20 From 1974 till 1985, I held the post of head
21 of the psychology department in that institute. In
22 1983, I was appointed as a partial professor at the
23 University of Leiden, and in 1985 I moved completely to
24 the University of Leiden, where I held the post of
25 experimental psychology.
1From 1987 till 1989, I was dean of the
2 faculty of social sciences, and, now, from 1997 till
3 today, I am the vice-chancellor -- or, as we say, the
4 rector magnificus, of Leiden University.
5 Q. Thank you. Please, Professor, could you now
6 tell us briefly something about your scientific work,
7 the papers you have published in your field and some of
8 the studies you have done in the area of human
10 A. Yes. By now I have published more than 150
11 publications. Many of them deal with problems of
12 perception and problems of memory, in which the
13 question usually is the problem of remembering what you
14 saw. Many of these publications are in the context, or
15 immediately inspired, even, by problems that occur in
16 the judicial process, like processes of, say, what
17 witnesses can see, what witnesses can or do remember,
18 what the reliability of eyewitness testimony is. I
19 have published several books on this problem, again,
20 usually inspired by very concrete trials in which such
21 questions were asked to me. I have acted as an expert
22 witness on such questions in, I estimate, more than 200
24 Q. Among other things, you have also testified
25 in this International Tribunal, I believe?
1A. Yes, I have testified in the Tadic case,
2 which I think was one of the first trials that took
3 place in this Court.
4 Q. Thank you, Professor. Now that we have
5 learned, at least in broad lines, something about your
6 professional activities and scientific work, can we go
7 on to your expert opinion provided for the needs of
8 this trial. To facilitate your presentation, I should
9 like to provide Their Honours and the parties a copy of
10 your expert opinion.
11 MR. PAR: I should like to ask the usher for
12 his assistance to help me distribute these documents.
13 THE REGISTRAR: This is Exhibit D58/3.
14 MR. PAR:
15 Q. Professor, upon the request of the Defence of
16 the accused, Vlatko Kupreskic, you have provided your
17 expert opinion on the identification of Vlatko
18 Kupreskic by Witness Q. Could you please tell us what
19 kind of information and data that you obtained from the
20 Defence, you used when providing your expert opinion?
21 A. Yes, I received, from the Defence, an
22 introducing letter explaining what the problem was they
23 wanted me to address, and as I have here a partial copy
24 of the trial record that represents -- which is the
25 most important for me -- some statements by the
1Witness Q and some other witnesses.
2 Q. Thank you. To have a more complete idea as
3 to the kind of letter that you used, I should again ask
4 the usher to help me provide Their Honours and the
5 Office of the Prosecutor with a copy of that letter.
6 Talking about this letter, Professor, you
7 said that it contained a certain number of data which
8 you used when drawing up your expert opinion. I would
9 suggest that I read out that part from the letter
10 containing that information, the initial situation that
11 we described in that letter in which the recognition
12 took place. As Their Honours have a copy of that
13 letter, and the Prosecutor, let me just read the part
14 that is relevant.
15 THE REGISTRAR: This is Exhibit D59/3.
16 THE INTERPRETER: Could a copy be placed on
17 the ELMO, please?
18 MR. PAR:
19 Q. The letter describes how the Defence
20 presented the situation under which recognition was
21 carried out, and so I'm reading from the letter. The
22 event and the conditions under which recognition took
23 place, according to the statements of the witness whose
24 testimony we are interested in, were the following:
25 "During the military activities in a Bosnian village
1on the 16th of April, 1993, around 9 a.m., a group
2 consisting of several civilians -- women, children, and
3 elderly people -- fled from their homes in order to
4 save their lives. Shooting from light and heavy
5 weapons was in course for several hours. Murders and
6 burning of houses were ongoing, and the group decided
7 to save themselves by escape. The group was moving
8 along a sheltered part of the terrain. Then they
9 climbed a small hill, and, at that point, they came out
10 on terrain where they were spotted by enemy soldiers.
11 The group at that point was faced away from the
12 soldiers. They had their backs turned on the soldiers,
13 and in one moment they heard loud swearing and threats
14 coming from the soldiers. The group turned around for
15 a moment. They looked at the soldiers, who were
16 standing approximately 60 metres away from them, and in
17 that moment, the soldiers started to shoot at the
18 group. On that occasion, one person was killed and two
19 persons wounded."
20 That is the part of the letter which we sent
21 to you, and in which we, as the Defence, described the
22 situation as we assumed it was.
23 In continuation of this letter or, rather,
24 our request for your expert opinion, we have asked
25 eight specific questions. That is, we asked you to
1give us your expert opinion regarding eight factors
2 which could have affected the reliability of the
4 In your written opinion, you responded to
5 each of these points, so I should like to ask you to
6 present those answers yourself, directly, in this
7 courtroom. Would you please begin your presentation
8 with the first part of your finding, where you noted
9 that there were two different modes of identification,
10 person identification, and could you describe briefly
11 both modes and then tell us which were the points that
12 we set and what your expert opinion about them is.
13 A. Generally, there are two situations in which
14 a problem of person identification may occur. One is
15 the situation in which a witness recognises a person
16 known to him or her already before the time of the
17 crime. So that's the problem of identifying,
18 recognising, a well-known person. That process can be
19 very fast. In a flash, you may recognise someone whom
20 you have known all your life, for instance. Later on,
21 the only thing you have to remember is the fact that
22 you recognised that person. You don't have to
23 remember, say, the whole image of that event. It is
24 sufficient, for instance, to recall, to remember, the
25 name of the person you have recognised. That's
2 Situation 2 is when, during a crime, you are
3 faced with a person you have never seen before, so you
4 can't try to remember the name of that person because
5 you don't know that person. Then, usually later on,
6 for instance, in an identity test, you are again
7 confronted with that person or a number of persons in a
8 line-up, and the question is whether you recognise that
9 person. In order to do that, it is necessary that you
10 have stored, from the time of the crime on, an image of
11 the person you saw, because in your head you have to
12 compare the image that you saw originally with the
13 image of the person you see now.
14 Now, these two processes are entirely
15 different, and the factors that influence the one are
16 not necessarily the same as the factors that influence
17 the other.
18 Now, in the case we are discussing today, we
19 are dealing with situation 1. The task was to
20 recognise a person that was supposedly known to the
21 witness long before. So the factors that are relevant
22 in this case are the factors that influence the
23 immediate recognition process. The problem of recall,
24 of remembering, is minute, is very small, because the
25 only thing that had to be remembered, in fact, is the
1name of the person who was seen there at the scene of
2 the crime. So factors that influence remembering or
3 forgetting are probably not very relevant because the
4 task to the witness was only to remember the name of
5 the person he saw. So decisive factors are factors
6 that influence perception, recognition on the spot, and
7 not factors that deteriorate your memory, because the
8 memory task is very slight.
9 Now, in the list of eight questions that you
10 gave me, some of the questions are in fact addressing
11 the perception situation and are therefore highly
12 relevant, and some address the problem of remembering
13 and are therefore probably not so relevant. So that's
14 the distinction that I made.
15 Now, in my letter to you, I started to
16 explain that in my opinion, the most relevant factor
17 is, in this case, the observation distance, which was
18 presented to me as being in the order of 60 metres.
19 That is a highly-relevant factor, because if you are at
20 such a distance that you can't see the face of a
21 person, then everything else stops, then there is
22 nothing to put into your memory. There's no memory
23 problem also.
24 The first question to be addressed is is it
25 possible to recognise a person known to you, known very
1well to you, at a distance of 60 metres in such a way
2 that we can safely say that no mistake is possible.
3 Now, at this point there is a problem that
4 can only be solved by the Court, and that is how
5 reliable should such a recognition be. Some
6 experimental data that I have provided to you is that
7 under optimal conditions, to our best knowledge, the
8 chances that you recognise a familiar person at a
9 distance of about 60 metres are something like 50
10 per cent correct, 50 per cent wrong, or worse, that
11 that would probably be the best performance. So I'm
12 not saying that you cannot recognise a person at 60
13 metres, but I am saying that 50 per cent wrong is not
14 highly reliable in a legal sense. It is quite possible
15 that the person would make a mistake. In my opinion,
16 it would be at least as likely that the person makes a
17 mistake as that the person would be correct.
18 Now, whether that level of reliability is
19 good enough for the Court, I cannot decide. I can only
20 give the information.
21 Now, if I want to go into some detail, I
22 would like to explain that we are confronted here with
23 a biological fact. Our eyes are built to perceive, and
24 inside the eye, say the area where, say, the light hits
25 the receptor is called the retina, and the retina
1contains a very large number of small receptors called
2 cones, and the cones are placed in some sort of mosaic
3 pattern, and it is clear that a detail that is smaller
4 than a cone cannot be clearly resolved, as we say it,
5 by the retina. A detail needs to cover at least one
6 cone, but it would be a lot better if it would cover a
7 number of cones so that the shape of that detail will
8 be perceived.
9 Now, the density of cones, the number of
10 cones on a square millimetre, is a biological fact and
11 is almost invariably the same for all people. It's not
12 the same for all living beings. Eagles have a much
13 denser placement of cones and they can see a lot more
14 details. But humans are not eagles. The density of
15 cones in the human eye is the same for all persons,
16 with very slight variations.
17 Another fact is that the details in a human
18 face that you need to see in order to make sure that
19 this is the one person, not the other person, are in
20 the order of half a centimetre. If you can't see
21 differences of half a centimetre, then you confuse the
22 one shape of an eye with another shape of an eye, the
23 one shape of a nose with another shape of a nose. In
24 order to recognise a person, you need to see details of
25 about half a centimetre, and if the distance, the
1observation distance, is so large that half a
2 centimetre on a face falls just within one cone, then
3 you cannot resolve these details anymore, you cannot
4 see them, and it becomes rather tricky to recognise a
6 These results are confirmed in a number of
7 studies, and I've done some of these studies myself,
8 and it is quite obvious that the details that the eye
9 can see at a distance of 60 metres are in the order of
10 two centimetres, not smaller, and definitely not half a
11 centimetre, and that's why, at a distance of 60 metres,
12 it becomes rather likely that you will make mistakes.
13 I'm still not saying that you can't recognise a person
14 at 60 metres, I'm only saying the likelihood of
15 mistakes become rather high.
16 Now, what I'm telling you is related to
17 optimal viewing conditions like perfect daylight, you
18 have all the time that you want, there is no haze, no
19 fog, no smoke. All these other factors can make it
20 more difficult to recognise a person. If there's no
21 perfect daylight, if there is smoke, if you see the
22 person for a very short time, all that makes it more
23 difficult. But even under optimal conditions, the
24 likelihood of a mistake would be rather high.
25 Q. Excuse me. If I may interrupt you just for a
2 Could you please tell us, this percentage of
3 error, how does it grow with distance?
4 A. In my letter to you, I gave you a small table
5 that is based on my own research, and if you take the
6 last column of that table with the heading "3.000," and
7 "3.000" refers to the elimination level and "3.000"
8 represents a normal day, somewhat clouded but normal
9 daylight, and then the numbers in that table give you
10 the ratio of correct answers to incorrect answers.
11 So, for instance, in the second row, if it
12 says "108," then there are 108 correct answers to one
13 wrong. So these numbers are odds, the odds of making a
14 correct identification.
15 Now what you see is that at 3, 5, 7, and 12
16 metres, the odds of making a correct identification are
17 rather high; 27, 108, 55, 90. There is always some
18 variation because these are experimental data, not
19 theoretical data. And suddenly at 20, it drops to
20 below 5. That sudden drop represents the moment where
21 suddenly the details of half a centimetre fall within
22 the area of one cone in the retina. If they fall over
23 several cones, there is no problem and distance is not
24 even so important. But at the critical point somewhere
25 between 12 and 20 metres, the details become too small,
1and then the ability to recognise a person suddenly
3 I have never done distances longer than 40
4 metres because, from this table, it's quite clear that
5 at 40 metres the likelihood of making errors is already
6 so large that it would be useless to research longer
8 Q. That is just what I wanted to ask you, "Why
9 don't you go further, after 40 metres," so now you have
10 given us the explanation for this procedure.
11 I interrupted you, Professor. When you were
12 talking about other factors influencing perception, you
13 mentioned the distance, the lighting and other
14 circumstances. So please continue, and I apologise for
15 interrupting you.
16 A. Well, this far I have discussed, in fact,
17 your question number 3, and I took that first because I
18 think that observation distance is the most crucial in
19 this case.
20 If you now go back to question number 1, the
21 fact that the witness was in life danger, in our
22 research, we call this the factor of the presence of
23 emotions, and what I have explained to you in my letter
24 is that emotions can have two effects, or generally
25 it's assumed that emotion has the effect that your
1field of attention becomes smaller. You focus your
2 attention upon one thing, the one thing that's most
3 crucial to you. The fact then of emotion can be that
4 you perceive that one thing better, and you may also
5 remember that better. In that sense, emotion can
6 improve the observation. But if you focus your
7 attention on a particular thing at the same time,
8 naturally you don't pay attention to some other things,
9 and the likelihood that you will perceive those other
10 things and remember them becomes smaller.
11 So the effect of emotions mean generally that
12 you will remember some things better and other things
13 worse. The only question is where did you fixate, what
14 was important for you at that time, and it's very hard
15 to tell because a person under high emotions is not so
16 rational. What will be selected as the thing to focus
17 at might not always be what is the most relevant at the
18 time of a trial.
19 So it's very hard to say what emotions in
20 this present case would have done. My science doesn't
21 give me enough guidance to say whether emotions would
22 have helped or would have had the opposite effect.
23 The question number 2 relates to the fact
24 that the witness looked just for one moment. Well, in
25 principle, you can recognise a person in one eye
1fixation, and you can make one eye fixation in half a
2 second, and I would say one moment probably is at least
3 half a second. That should be enough for recognising a
4 person that you know so very well. So that should not
5 be a problem, in principle.
6 Question number 3, I answered already.
7 Question number 4 is the problem that the
8 person who was recognised, whoever he was, was standing
9 in a group, so there was more to see than just that one
10 person. Now, what I reckoned in my letter, that if
11 this were a closed group of people, standing together,
12 then, at a distance of 60 metres, you don't need more
13 than one fixation to see the whole group. If you look
14 at one point, there's a certain area around that point
15 that we can see without moving our eyes; we call that
16 the stationary field. Other things, outside this
17 stationary field, can only be seen if we move our eyes,
18 and eye fixations take time. So the larger the group,
19 the more fixations you need to make and the more time
20 you need. But if four persons stand closely together,
21 they can be seen in one eye fixation, and the fact that
22 there is a whole group doesn't matter so much; they can
23 be seen all at the same time. So that, in principle,
24 should not be a problem.
25 Question number 5 was the age of Witness Q.
1Now, age-related eyesight problems are usually problems
2 of reading, problems of seeing at a very short
3 distance; usually the eyesight for a long distance
4 remains the same. I say "usually" because of course
5 there are individual differences. But without further
6 information about Witness Q, I can only say, if he is a
7 normal person, at 55 he will have already some reading
8 problems and probably needs eyeglasses for reading, but
9 not for a distance. If the opposite is claimed, the
10 obvious solution, to find an answer to this question,
11 is to send him to an ophthalmologist and ask him to
12 study his eyes. I can only tell you what usually would
13 happen, so I would say that the age of Witness Q with
14 respect to his eyesight is probably not relevant.
15 Question Number 6, the fact that other
16 persons who were also watching the scene couldn't
17 recognise anyone, well, what I explained in my letter,
18 I'm not surprised at that, because, in fact, I do not
19 expect that people would correctly recognise another
20 person at a distance of 60 metres, so the fact that the
21 others didn't recognise anyone needs no further
22 explanation. What we need to explain, how it was
23 possible that one of them still, at a distance,
24 recognised someone. So there is no real conflict. Of
25 course they didn't recognise anyone.
1Seven -- and here we go into the memory
2 problem -- the fact that Witness Q could not explain
3 what kind of clothing the person he saw, and he said he
4 recognised, was wearing. Well, in order to recognise
5 him at that time, on the spot, he didn't need to pay
6 attention to the clothing of that person; the face is,
7 of course, the most important thing if you want to
8 recognise anyone. And for remembering who he saw, he
9 only needed to remember the name of the person. It's
10 not necessary at all that he also remembered the image
11 that he saw, so that later on he could tell you, "On
12 that image of this person, I can now also tell you
13 which clothes he was wearing."
14 So, given that the clothes of this person
15 were probably not relevant to him at all -- usually the
16 weapon is the most important thing, and then the face,
17 but the clothing is not relevant -- and the fact that
18 in order to make his testimony he needed only to
19 remember the name of that person, it's not surprising
20 that after some time, when he finally made his
21 testimony, he didn't remember the clothing. So that's
22 not a problem.
23 Question Number 8 is a rather complicated
24 question, and if I may, I need some time to explain why
25 that is complicated, because Question 8 is related to
1what I say, as a general term, called "suggestion." If
2 we see something that is not very clear and we store
3 the unclear information in our heads, then it's quite
4 possible that what we call "post-event information,"
5 information that reaches us afterwards, will sharpen
6 that image, will affect that image, and also may change
7 that image, because the image of what we saw, in our
8 heads, is not stable at all but is constantly
9 reprocessed in the context of knowledge that we
11 Human memory is not like a video recorder,
12 where the recording stays unchanged. Human memory is
13 very active, is very much alive, and information that
14 we have is not simply stored and recalled when we need
15 it; no, it's constantly processed in the context of
16 knowledge that we receive. That's very useful for
17 people, very useless for a court, because we would
18 rather like witnesses to be like video recorders, but
19 unfortunately, they are not.
20 Now, your question is the fact that later on,
21 the witness received information about the person he
22 recognised -- now living in his house, if I am
23 correct -- may have affected the image that he
24 remembered, and I can, of course, not describe what
25 happened; I can only describe what may happen in a
1person. I must say the most important condition for
2 post-event-information-induced changes to occur is that
3 the first observation is not totally clear. If I have
4 a totally clear initial observation, probably there's
5 no new information that may change that, but if it's
6 not clear, if it's vague, then there is an opportunity
7 for what you may call a sharpening of the image as a
8 consequence of receiving new information.
9 Now, what I would say is that seeing a person
10 at 60 metres creates not a sharp image of a particular
11 face, because the critical details are not resolved in
12 the retina. It creates a vague image that may be
13 recognised correctly, but also maybe is confused with
14 another person. Now, that vague image is a perfect
15 basis for post-event information to have an effect, and
16 I listed in my letter a number of pieces of information
17 that could have such effect, like the fact they were
18 standing in front of a certain house, or some facts
19 that are known about the accused -- that he belongs to
20 some group, or that he might have had a weapon; all
21 sorts of information that may come later may influence
22 that image.
23 It is very hard to limit the sort of
24 information that can have that effect, and I'm not
25 perfectly aware of all the information that has been
1presented to Witness Q about the accused, so it's very
2 hard for me to even guess what has happened. I only
3 can say that the starting position of a vague image,
4 seen at a distance of 60 metres, is a good starting
5 point for suggestive post-event information to have
7 Now, an important aspect here is that if you
8 have a very clear image, you can also say immediately
9 whom you have recognised. Recognition is usually a
10 process that happens very quickly. You see something.
11 You say, "I know who that is." Recognition is not
12 something that is spread out over a month, so that
13 first, you didn't know it; after several months, you
14 know it. That process, very gradually, you start to
15 realise what or whom you saw, is totally different from
16 immediate perception. It is a construction. When you
17 start to realise, you use all sorts of information to
18 make the vague image that you have in your head
19 sharper, and at the end, you know -- "Ah, but now I
20 know what that vague image in fact means." But that's
21 not perception; that is reconstruction, and
22 reconstruction is very much influenced by information
23 that you receive during that period.
24 So the two important elements here, although
25 I cannot answer your question whether suggestion has
1occurred, but the two important elements are the
2 initial position is good for suggestion, because it's a
3 vague image, and as far as I could tell from the
4 information that I received, recognition was not
5 immediate. It was a process that took a while, and
6 only after a certain amount of time, Witness Q
7 testified that he knew who that was.
8 Q. I have a question with regard to that. I'm
9 interested in knowing -- let us assume, under
10 suggestion, some kind of suggestion, the suggestion we
11 talked about a moment ago, if he performs
12 identification, I'm interested whether that individual
13 intimately believes that he is speaking the truth and
14 has had a clear identification, the subjective views of
15 that individual that they have recognised the person.
16 A. Yeah. That's an important aspect of all
17 eyewitness testimony, the certainty, the conviction
18 that the eyewitness has, the sincere and strong belief
19 that he is speaking the truth. There is an enormous
20 amount of research on the relationship between
21 certainty, certainty of the witness, and how often the
22 witness is correct -- and I'm not talking about two or
23 three studies, but at least about a hundred or so.
24 The bottom line of all those studies is that
25 the relationship between certainty and correctness is
1very, very weak. There are many witnesses who are
2 perfectly certain, and they are wrong. And there are
3 many witnesses who are totally uncertain, but they are
4 right. The bottom line is that the amount of certainty
5 expressed is much more an aspect of the personality of
6 that witness. Some are very certain witnesses --
7 that's the way they are -- and some other people are
8 always uncertain, even when they know the answer
9 perfectly well. It's more an aspect of personality
10 than an aspect of the quality of what they saw or what
11 they remember.
12 So it's quite likely that an eyewitness is
13 totally sincere, totally honest, very convinced, does
14 not assume that he or she can make a mistake and still
15 is very wrong about it.
16 Q. Thank you. Professor, I think that we have
17 mostly covered all the areas that you touched upon in
18 your expert report, and so finally I should like to ask
19 you to tell us your final conclusion, that is to say,
20 to tell us what your opinion is as to the truthfulness
21 and correctness of the identification of Vlatko
22 Kupreskic done by Witness Q, on the basis of the facts
23 that you had at your disposal.
24 A. My conclusion is that the most important
25 factor is the viewing distance, and the viewing
1distance is prohibitive for making a good, reliable
2 recognition. My data show that some subjects in
3 experiments that have been done are still able to do
4 that, but more than 50 per cent are wrong. As I said,
5 the question whether that sort of a risk in
6 identification is acceptable is totally up to the
8 Q. Deviation from that, you said whether it was
9 reliable, unreliable, the degrees of reliability?
10 A. Yeah. It's always difficult to express
11 things in words that, to my mind, are perfectly well
12 expressed in numbers. Whether, say, a probability of
13 higher than 50 per cent that you are wrong, whether you
14 would call that unreliable or slightly reliable or
15 reliable, I think it's matter of words. What I have
16 found is that to all probability, you must assume here
17 that the likelihood of making a mistake at 60 metres,
18 in the given conditions, is higher than 50 per cent. I
19 don't call that reliable, but it's a matter of words.
20 I would rather testify to the data that I have reported
21 than to how you express that in words.
22 Q. I think we have understood each other. Thank
23 you very much, Professor.
24 MR. PAR: Your Honours, I have no further
25 questions. I should just like to propose that these
1two documents be tendered into evidence as Defence
2 Exhibits D58/3 and D59/3.
3 JUDGE CASSESE: Thank you. And I see no
4 objection from the Prosecution. They are admitted into
6 Counsel Pavkovic?
7 MR. PAVKOVIC: Good morning, Your Honours. I
8 think you were asking whether any other of the Defence
9 counsel have any questions; I have one question for the
11 Cross-examined by Mr. Pavkovic:
12 Q. Good morning, Professor. I am counsellor
13 Petar Pavkovic. Perhaps -- that is to say, I feel that
14 this question should perhaps be given a broader, more
15 complex answer, but I would be satisfied for the
16 moment, and for these purposes, to remain at the level
17 of a stand of principle. I should like to ask you
18 briefly, and in principle, to tell us what the effect
19 of time is, and the passage of time, on memory and the
20 ability to reproduce what was once remembered.
21 A. You're perfectly right that you're asking a
22 rather complicated question, because obviously the
23 answer depends very much upon what it is you want to
24 remember. Like, a telephone number can be forgotten
25 within a few seconds, but the fact that you won a case,
1which can be announced to you in the same amount of
2 time, you will probably remember your whole life. So
3 it is not easy to say what time is doing to memory.
4 Some things will simply be never forgotten; time is
5 irrelevant. Some things are very quickly forgotten,
6 and everything in between is also possible.
7 Now, we know that remembering a face that you
8 have never seen before is, indeed, influenced by time.
9 Studies that we have done related to bank robberies
10 show that, say, after six weeks, for instance,
11 remembering the face of the bank robber becomes
12 problematic. I'm talking about six weeks. But
13 remembering that you have seen someone whom you have
14 known all your life, so that you don't have to remember
15 the face of a bank robber, but only the name of a
16 person, for instance, if you were in a bank and
17 suddenly one of your colleagues comes in and appears to
18 be a bank robber, well, that's rather surprising to
19 you, and you won't forget that; not within six weeks,
20 not within six months, and not even within six years.
21 Now, there is a second problem, which is what
22 we call the problem of rehearsal. To some things in
23 our life, we are reminded all the time, and that means
24 that in our memories, these things are refreshed all
25 the time. Now, if we refresh some memories every day,
1we are simply not forgetting those things. Other
2 things, to which we are never reminded, may gradually
4 Now, the problem with a face is that it's
5 very difficult to refresh the picture of a face in your
6 memory if you are not shown the picture. So if you
7 have to remember the face of a bank robber, but they
8 have not caught the culprit yet, so you are not
9 confronted with that face, in the meantime, the
10 witnesses may forget the faces because they are not
11 refreshed. But if you have to remember a name, you can
12 refresh that yourself. Every time you tell the
13 story: "This is what happened to me, this person did
14 that to me," the name is refreshed. It can happen
15 several times a day. And then there's no reason why
16 memory would fade at all.
17 So there are two factors, I think, which
18 makes it rather urgent that if you have a question, you
19 should be rather specific, because in general, the
20 question cannot be answered.
21 Q. Thank you, Professor. I'm satisfied with
22 your answer. Everything else would require far more
23 time and far more facts. Thank you very much.
24 MR. PAVKOVIC: Thank you, Your Honours. That
25 is all I wanted to ask.
1JUDGE CASSESE: Counsel Susak?
2 MR. SUSAK: Mr. President, I'm going to ask a
3 question now as to the inquisitiveness of the expert
5 My name is Luka Susak. I am the Defence
6 counsel of Drago Josipovic.
7 Cross-examined by Mr. Susak:
8 Q. You mentioned the distance of recognition and
9 the distance in viewing. I'm interested in knowing
10 what is the greatest distance at which a person can be
11 recognised? I have, of course, in mind that you said
12 that sometimes there is absolute certainty, other times
13 not, but I'm interested in hearing an answer. At what
14 distance can an individual be recognised?
15 A. Yes, it's good that you ask this question,
16 because it gives me an opportunity to point again to
17 the table, which is just the result of one study but it
18 explains the principle.
19 If you look at recognition rate at a distance
20 of three metres, which is as far apart as we are now,
21 probably, what you see is that even with perfect
22 illumination, recognition is not perfect. There's
23 always a likelihood that someone makes a mistake. The
24 more one person resembles another, the more likely that
1There is simply no situation in which, as a
2 psychologist, I could say, "There, no mistakes are
3 made." Only, in such conditions, that the likelihood
4 of a mistake becomes very, very small, so that for
5 daily use we can say it's perfect.
6 On the lower side, at the very long distance
7 it's not going to zero. It's very difficult to say
8 there it's impossible to make a correct identification,
9 because even by guessing, you might be right.
10 So the question is not at what distance is it
11 impossible to recognise a person. The question really
12 is, I think, at what distance are recognitions not
13 reliable enough to be used as evidence. I phrase it
14 that way because part of the problem is with me, I can
15 say something about the rate, rate of mistakes, and
16 part of the problem is with you, as lawyers, because
17 you determine what reliable evidence is. But it's not
18 a question of perfect recognition or no recognition at
19 all. We're always dealing with something in between,
20 and always the question of what is reliable enough to a
21 court must be addressed. But for all practical
22 purposes, that's what I have published on this
24 I would say that recognitions at distances
25 below 15 metres are about the best that a Court can
1get. There's little hope that you can improve upon
2 recognitions at distances below 15 metres. Above 15
3 metres is not perfect anymore, and if you want the best
4 evidence, I would say then use recognitions at
5 distances shorter than 15 metres. But I would never
6 say all recognitions at distances above 15 metres are
7 wrong, because they aren't. Above 15 metres, the
8 question becomes how reliable do we want it to be. But
9 that's your problem, not mine.
10 Q. Thank you, Professor. Another short
11 question, and it will be more concrete.
12 Can an individual be identified at 200 metres
13 if they are sitting down?
14 A. Can you explain to me what you mean by "if
15 they are sitting down"? Do you mean the face of that
16 person is visible, because --
17 Q. Yes, the face is visible but not the
19 A. In general, movement and posture are minor
20 factors with respect to recognising a person. Unless a
21 person has a very specific way of moving, for instance,
22 because he's crippled or so, it is very difficult to
23 recognise and very tricky to recognise a person from
24 posture or movement.
25 Really, the most important factor is the
1face, and if you look at studies that compare
2 recognising living and moving persons with recognising
3 the same person but only from a picture of their face,
4 there's hardly any difference because the face is
5 really decisive.
6 With respect to posture and movement, there
7 are so many people who have the same posture or move in
8 the same manner that it's really rather tricky to
9 accept identifications on the basis of those.
10 So the question really is can you see the
11 face, and as I have argued already for 60 metres, the
12 likelihood that you would make mistakes at a distance
13 of 60 metres is so high that I would never call that
14 reliable, and at 200 metres it's obviously even worse.
15 Q. Professor, I just asked for an answer to
16 whether an individual can be recognised at 200 metres
17 or not, an individual sitting down with their face
19 A. You're bringing me in a somewhat difficult
20 position by asking me "Yes" or "No," because what I
21 have explained is, unfortunately, not a "Yes" or "No"
22 thing. I would never say that if you see a person at
23 200 metres and you think, "This is so and so," that you
24 would always be wrong. I'm only saying the likelihood
25 of making a mistake at a distance of 200 metres is
1very, very high.
2 MR. SUSAK: So as far as I was able to
3 understand, an average person could recognise somebody
4 sitting at a distance of 200 metres. I'm saying this
5 out of my own curiosity, and I have no further
7 Thank you.
8 JUDGE CASSESE: Thank you. Mr. Terrier?
9 MR. TERRIER: Thank you, Mr. President.
10 Good morning. I'm Franck Terrier, one of the
11 counsel for the Prosecution. As you have experience
12 with trials, you are fully aware that I will now
13 proceed with the cross-examination.
14 Cross-examined by Mr. Terrier:
15 Q. First of all, Professor, could you tell us
16 whether you familiarised yourself with the transcripts
17 that were communicated to you by Mr. Krajina, I
18 believe; the trial records, in other words?
19 A. Yes. In the letter I sent to Mr. Krajina, I
20 identified the pages of the trial records that I have
21 used for familiarising myself with the situation that I
22 was to study.
23 Q. Professor, in that case, you were able to
24 correct two involuntary errors in the introductory
25 letter of Mr. Krajina. The first is that he said that
1a group turned around when they were shot at and looked
2 at the soldiers for a moment, and the second error
3 being that those soldiers were 60 metres away. I
4 should like to underline that it follows from the
5 record that the group didn't turn around but some
6 members of that group, and this could affect your
7 answer to question number 6 or, rather, 8, I think.
8 The second remark I should like to make,
9 Professor, at the beginning of this cross-examination,
10 is that the witness spoke of a distance of 50 to 60
11 metres, not a distance of 60 metres.
12 I should also like to ask you to take into
13 account the hypothesis that the distance might have
14 been smaller than 50 or 60 metres, that it could have
15 been 40 metres, because I should like to convey to the
16 trial that we have new elements. That evidence is not
17 presented in court now. I'm just presenting it in a
18 hypothetical form to gain benefit from your experience
19 and knowledge in these matters. So I am asking you to
20 take into account this hypothesis of a distance of some
21 40 metres.
22 I should like to check that I fully
23 understood your conclusions.
24 You say that regarding recognition of a
25 person known from before, a familiar person, the risk
1of error in identification increases with the distance,
2 and particularly when the distance increases to above
3 12 metres. And you say that at a distance of 40
4 metres, the ratio between hit and false identification
5 is 1 to 1, that is, that the risk of error is 50
6 per cent.
7 Did I understand you well, Professor?
8 A. Yes. If I take your last two points, that's
9 what I said.
10 Q. You also say, at the end of your letter to
11 Mr. Krajina, I think, that 60 metres is four times the
12 required distance for recognition to be considered
13 acceptable, so that the required distance would be 15
14 metres. You also say that at 60 metres, identification
15 remains possible, is still possible.
16 To take up a question that has just been made
17 by Attorney Susak in a slightly different manner, I
18 should like to ask whether you can tell us, bearing in
19 mind the physiological performance of the human eye,
20 what is the maximum distance at which one can recognise
21 a face without taking into account other factors, the
22 memory suggestions and so on, simply the physiological
23 performance of the human eye. What is the maximum
25 A. Should I address all the points you have made
1in order, so that we start with the fact that they all
2 turned around, or do you want an answer first to the
3 last question?
4 Q. First the last question, please.
5 A. Okay. I would say that the legal sciences
6 are entirely different from my science. It would be
7 highly interesting to study the physiological
8 performance of the eye without memory and anything
9 else. Unfortunately, in humans, the eye is connected
10 to memory. We cannot disconnect it. It's not possible
11 to answer the question of what the eye can do if not
12 connected to the brain. It is connected to the brain,
13 and it must be connected to the brain because
14 recognition occurs in the brain, not in the eye. But
15 at the same time, all other contributions that the
16 brain can make are made during recognition. It cannot
17 be helped.
18 So as an example, your problem of at what
19 distance can you recognise a person, take the following
21 We know that through a door at 200 metres,
22 say, two persons can enter. It's either you or the
23 President of the Court and there are no other
24 possibilities. I know that. Then at 200 metres, I
25 will be quite safe in recognising whether it is the
1President of the Court or you, because I don't need to
2 identify small details in the faces. I only need to
3 identify very rough details and that's enough, and you
4 are sufficiently different to do that at 200 metres.
5 On the other hand, when two people who are
6 more or less alike must be distinguished, I need to see
7 details in their faces, and then it very soon becomes
8 necessary to be at a distance of 15 metres.
9 So the question is not what can the eye do
10 but what information needs the eye, on top of other
11 information that the brain already has, to make a
12 correct identification.
13 But it can't be helped that the problem is
14 always that complicated, because we are not talking
15 about the eye. The eye is only, say, the beginning of
16 the process, it's the camera part, but the recognition
17 is taking part in the brain on the basis of what
18 information the eye is sending, and there's so much
19 more information in the brain that the question cannot
20 be answered in general.
21 But if we are specific about the situation
22 you are dealing with, which is people are fleeing, they
23 are looking back, Witness Q is looking back, he sees
24 four people, now the question is who are these people,
25 and one he seems to recognise. Now, in principle, it
1could be a large number of people who are standing
2 there. It's quite possible that they are people he's
3 never seen before. But he seems to recognise one
4 person he knows very well, and he is so certain about
5 that that he testifies here in this Court it could not
6 have been someone else.
7 Well, in order to be reliable, you must make
8 sure that it was not a person who looked rather like
9 the person he knew before, and in order to do that, to
10 make that distinction at a reliable-enough manner, he
11 needs to resolve small details in the face, because
12 there can easily be two people who look rather alike,
13 but the details in the face differ when you look at
14 small things like half a centimetre.
15 So in my opinion, in order to give reliable
16 evidence that it's this person he saw and not possibly
17 any other person, he needed to resolve small details,
18 and he could do that only at a distance of 15 metres or
19 below. That's why I would say if you limit it to the
20 question that you have here and not broaden it to very
21 general questions about what people can do in all sorts
22 of circumstances, you're talking about this condition,
23 then I would say in this condition you need a distance
24 of 15 metres or below.
25 I'm sorry to give such long answers, but
1you're asking very complicated questions.
2 Q. Professor, I listened to you with a great
3 deal of attention and interest, but I'm still going to
4 ask you another question which may be even more
6 I see that there is a clear distinction, at
7 least at this stage of our discussion, between the
8 variables allowing one to say that recognition was
9 precise or that there was a risk of error, and then on
10 the other hand the question of reliability, that the
11 reliability of recognition is something quite
13 In my understanding, that is not up to the
14 expert. It is not the responsibility of the expert but
15 the responsibility of the Judges, who have to take into
16 account other elements of assessment, among others, the
17 fact that the presence of that recognised person in
18 that spot was corroborated by other testimony, for
19 instance. So the question of reliability is up to the
20 Judges, whose sovereign right that is. At least that
21 is my opinion. What I would like to look into are the
22 variables which lead us to think that a recognition was
23 precise or that there may be a certain percentage of
25 So I come back to the question which I
1consider important, because in your reply, you
2 mentioned considerations related to eye physiology. I
3 think that an analysis is possible, because when we go
4 to see an optician, we are asked to recognise A, B, C,
5 and D, and we know that beyond a certain distance, we
6 cannot recognise those letters.
7 So my question is: Is there a distance
8 beyond which recognition of a face is physiologically
9 impossible because it is beyond the capacity of the
10 eye, similarly to what we do when we visit an eye
11 doctor and are asked to recognise letters?
12 A. I think the example of the letters is a very
13 good one to illustrate the problem that I have.
14 At a very large distance, you may be
15 presented with a letter, and if you just guess, you
16 have a probability of 1 in 26 that you give the correct
17 response. I, as a psychologist, cannot know what you
18 did, whether you guessed or whether you saw it. I can
19 only say if the distance increases, the performance
20 levels go down to 1 in 26 correct, and probably they
21 won't go down to zero. The same is with face
22 recognitions. The performance goes down with distance,
23 but they usually do not go down to zero because there
24 is always other information in the head of witnesses
25 that helps them to guess.
1Obviously, you don't want guessing
2 witnesses. You want to get witnesses who testify to
3 what they saw in a reliable manner, and therefore when
4 you approach levels of performance that may be
5 interpreted as just guessing performance, you should
6 become very careful. You should become very careful
7 even when the performance level is not zero, because
8 the guessing level is above zero.
9 Now, in the situation we are talking about,
10 the question of guessing is not irrelevant, because if
11 in that group of persons standing there and shooting
12 there was someone he knew, how many could that have
13 been, how many people were in the area? So if he felt,
14 "I know some of them," then guessing might have led
15 him to this observation, so the guessing level is a
16 reality. The performance is not going down to zero.
17 But quite rightly, you say that the only
18 contribution that I can have is I can present you with
19 some results of studies that we did. I hate to repeat
20 myself, but the bottom line is, of course, I will never
21 say that at distances, and we're not talking about
22 miles and miles because obviously there is no
23 recognition possible anymore, but at a distance we're
24 talking about here, 60 metres, or 50, or 70, it doesn't
25 matter so much, performance is still not at zero. It
1isn't. I can't help it. It's not at zero. But in the
2 neighbourhood of 40 metres, already there are as many
3 wrong identifications as correct identifications, and
4 at longer distances, it's getting worse.
5 Unfortunately, you're just, in your problem,
6 hitting the area where it's not ideal, it's not even
7 reliable, I would call, and it's not zero. I can't
8 help it. That's the distance under discussion. That's
9 how the situation grew.
10 Obviously, it's the responsibility of the
11 Court to say, "What criteria, with respect to
12 eyewitness reliability, do we pose?" That's your
13 problem. I can only sketch for you different
14 likelihoods of making mistakes, and whether you think
15 that's good enough, in the light of all the information
16 that you have received in the meantime and I don't
17 have, I will not and I cannot, of course, make that
18 judgment for you.
19 Q. I understand very well, Professor. I am
20 going to put that question in a slightly different
22 I am trying now to examine, and I'm asking
23 you to say whether at a distance of some 60 metres,
24 there is any obstacle linked to the physiology of the
25 eye which makes recognition either impossible or
1extremely dangerous, and I'm referring to eye
2 physiology again without referring to the brain or any
4 Going back again to the doctor's office, if
5 the doctor asks me to recognise A, B, and Z, and if I'm
6 trying to guess the letter, to guess the letter, that
7 is only normal. Because this is an experimental
8 situation, emotions, memory, feelings do not intervene
9 or they do so to a minor extent, can we say that there
10 is a physiological difficulty for the eye to recognise
11 an object or the size of an object at a distance of 60
13 A. Yes. If you refer to the letters in the
14 office of the ophthalmologist, the technician, the
15 answer is quite simple. The letters are constructed in
16 such a way that you need to resolve, as we say, one
17 minute of arc, and that's the density of cones in the
18 retina. That means for observation at 60 metres, that
19 the thickness of the lines, of the letters, needs to be
20 two centimetres. At 50 metres, the letters of the
21 doctor are half a centimetre. Now, the doctor does it
22 in a different way. He keeps the distance constant,
23 because you are staying where you are, and he changes
24 the size of the letters, because that's more
25 convenience than increasing the distance of the
1observer. But the rule is the same. You can't see the
2 letters in the office of the optician if you cannot
3 resolve one minute of arc, which coincides with the
4 sizes that I gave you. These letters are, of course,
5 specially constructed to make it very clear whether you
6 can see them or not see them. Unfortunately, faces are
7 not entirely like letters; they are not constructed for
8 optimal distinction between seeing or not seeing. So
9 the question is much easier for letters.
10 Q. Could we, for a moment, examine the table
11 attached to the letter that you sent to Mr. Krajina.
12 The two variables that were introduced are a distance
13 of 3 to 40 metres, and illumination, 0,3 to 3.000 lux.
14 Could you tell us what level of illumination
15 corresponds to the daylight at 8.00 in the morning, to
16 normal daylight, in the morning, in Europe?
17 A. It depends on the date.
18 Q. Yes, you're quite right, Professor. I'm
19 talking of the month of April, in the northern
21 A. Then probably -- you're probably very close
22 to 3.000, so it's -- the right-hand column represents
23 normal daylight. 300, which is the step below, then
24 you are already in the dusk, so normal daylight would
25 be represented by 3.000, and it can be a lot brighter
1if you have bright sun. The problem is that what you
2 can do in laboratory, where you try to control the
3 conditions, the best you can achieve is something like
4 3.000, so that's why we didn't go any higher; but 3.000
5 is a fair representation of a normal day, if you're not
6 on, say, a beach, in the burning sun.
7 Q. And 2 lux corresponds to what illumination,
9 A. I didn't present a description of what it
10 means. 0,3, the darkest, is in an area where there is
11 no artificial illumination, in the night, with no
12 moon. And then 2, you might say, is in the same area,
13 with a very bad illumination, and then you slightly go
14 on, gradually, to improving the situation.
15 2, 3, and 5 are especially included because
16 many questions that arise in court is recognising
17 people in city conditions, and at night, and 2, 3, and
18 5 are situations that you can encounter in city
19 conditions at night, in various roadways, with a lot or
20 not a lot of illumination. And that's why I chose 2,
21 3, and 5, closer to one another, because that's a
22 relevant area, and then I go, with somewhat larger
23 steps, to the lighter part.
24 Q. So to read correctly this table, we should
25 say that at the level of 2 lux and a distance of 12
1metres, we come across a figure of 2,6, which means two
2 correct recognitions against six incorrect
3 recognitions. Is that the way we should read these
4 results in the table?
5 A. No, the numbers in the table are odds. They
6 are always so much to 1. So the number that you
7 mentioned is 2,6 to 1; 2,6 correct to 1 incorrect.
8 It's always so much to 1. And if we go to the right,
9 then at 10 lux, it's 28 to 1, and 67 to 1. Always so
10 many correct to 1 incorrect.
11 And what you see in the bottom line, where it
12 goes below 1, so there, it can be like 0,2 to 1, which
13 means 0,2 correct to 1 incorrect; that means far more
14 incorrect to correct. So if the number is 1, the
15 number of correct and incorrect identifications is the
16 same, is equal. If you go below 1, there are more
17 incorrect identifications than correct. And what you
18 see at 3.000 lux, at a distance of 40, it's 0,8 to 1,
19 which means it's almost 50-50. Almost 50-50. Slightly
20 below, but that's not so important. These are, of
21 course, experimental data.
22 Q. Precisely, could you tell us what was the
23 protocol of the trial that was applied in this test?
24 A. The protocol is that people see a face under
25 these conditions, and then immediately, without any
1delay -- so it's a retention time of zero seconds, you
2 may say -- they have to point out on the display whom
3 they saw. The display may have the face that they
4 saw. That's the situation of a line-up where the
5 suspect is indeed guilty, and then you can make a hit,
6 because if you point out the correct person, that's
7 what's called a "hit." The other half of the subjects
8 see a display of persons, and the one face they saw is
9 not present. That's the situation of a line-up in
10 which the suspect happens to be not guilty; that's not
11 the person they saw before. In that case, they can
12 make a false alarm; if they still point out someone,
13 that's called a false alarm.
14 The numbers represented in this table are the
15 ratio of hits and false alarms. That's the ratio of
16 correct identifications and mistaken identifications.
17 In order to do that, you need the two conditions of
18 what we call "target-present line-ups" and
19 "target-absent line-ups."
20 Q. Who were the subjects who were looking, who
21 were asked to identify?
22 A. The subjects were students, so young people
23 at our university, with perfect eyesight. So this is
24 about the best subjects can do.
25 Q. And the face that they were asked to
1recognise, was it a real face, or was it a photograph?
2 A. They were photographs.
3 Q. As for the persons they knew from before and
4 they were asked to recognise or not recognise, were
5 they photographs of members of their family, or just
6 people they knew?
7 A. No, as I explained in my letter, they were
8 photographs of people they did not know. I have
9 explained that in my letter, in the point -- on page 2,
10 at the bottom paragraph. "The results in the appendix
11 represent ..." -- and so on. And what I have pointed
12 out in that letter is that what I want to illustrate
13 with these data is the sudden drop that occurs between
14 12 and 20 metres, because that drop is not related to
15 anything in the brain, where the effect of persons
16 known or not known to you is located, but to something
17 in the eye. The eye cannot resolve the face any more,
18 and that's why you get this sudden drop.
19 If you're interested, you may compare the
20 effect of what happens if you go from the right in the
21 table to the left, where you go from much light to less
22 light. There you see a gradual decrease of the
23 numbers. There's not a sudden drop, because the eye
24 does not react to lower light levels, a sudden drop,
25 it's not a system of "go" and "no go." But if you go
1from the top to the bottom, there you see the sudden
2 drop. You see it in all columns. It is there for 10
3 lux as well as for 3.000 lux, and that is because you
4 cross a certain -- say, "go/no go" system in the eye.
5 That's the point I wanted to illustrate, and that
6 simple biological piece of information is true for
7 faces that you know and you don't know. It's simply
8 not resolved any more. The eye stops. That's the
9 point illustrated in this table.
10 Q. I go back to the protocol of the trial to ask
11 you for two or three points of clarification. The
12 photographs that these students were asked to
13 recognise, were there several, or was it one
14 photograph? Were there several photographs shown?
15 A. Yes, a large number of photographs was used,
16 of course, for several reasons. One is, if you ask a
17 student to recognise a number of people and they're
18 always the same, it becomes very easy, so you can't do
19 that. The other is that the way you test their memory
20 is you present them with a photographic line-up of
21 faces, and you ask them to point out, "Which is the one
22 you saw?" For that, obviously, you also need a large
23 number of photographs to pick from.
24 Q. But my question was more specific. When this
25 subject was shown a photograph, did he see only one
1photograph, or several in a line-up?
2 A. The experiment, of course, consists of two
3 stages. First you are confronted with one face, and
4 then immediately thereafter, you are confronted with a
5 photographic line-up in which you have to point out
6 which of these people is the one you saw. So in step 1
7 you see one face, and in the next step you see a
8 line-up of several faces.
9 Q. As we are interested in the recognition of a
10 person known from before, could you tell us, what was
11 the type of link that existed among those people on the
12 photographs and your subjects, your students?
13 A. As I explained on page 2 of my letter,
14 there's no link. That's not the purpose of this
15 experiment, and it's not the reason why I refer to it.
16 The reason is only that -- the sudden drop between 12
17 and 20 metres, where the eye cannot resolve faces any
19 Q. I understand. You explained that in your
20 letter. But we are interested in this very specific
21 question, which is rather different from the one you
22 dealt with in your trial, that is, recognition of a
23 person known from before. Because now we, or rather I,
24 have to try and check and verify whether this situation
25 in the trial can be transposed to reality. I'm asking
1you, what were the faces which these students were
2 asked to recognise? Whose faces were they? Were they
3 film stars, people known? Was there an emotional link
4 between those subjects and the photographs -- their
5 mothers or fathers?
6 A. No. No link, as I explained in my letter.
7 There is no link. They are faces of people taken in a
8 different city, so it's highly unlikely that they would
9 ever have met these people before.
10 (Trial Chamber confers)
11 JUDGE CASSESE: Do you have a lot more
12 questions, Mr. Terrier? Yes?
13 MR. TERRIER: Yes, I'm afraid I have.
14 JUDGE CASSESE: Because we have this problem
15 with Judge May, who needs to preside over a hearing in
16 another chamber. I understand, however -- yes?
17 And then Mr. Par will probably have more
18 questions, and I, too, have some questions.
19 (Trial Chamber confers)
20 JUDGE CASSESE: Mr. Terrier, take your time,
21 because we have just decided to continue until 11.30,
22 and I hope three-quarters of an hour will be
24 MR. TERRIER: I shall do my best,
25 Mr. President.
1Q. Professor, I understood that the students
2 were asked to identify photographs of people they
3 knew. Am I wrong?
4 A. Yes. As I explained -- I think I was rather
5 careful to explain that -- in the bottom paragraph of
6 page 2 of my letter: "The results in the appendix
7 represent the identification of people not known
8 before." Not known before. "There is a retention
9 period of zero seconds, and it is therefore not wholly
10 representative for the recognition of familiar people,
11 but the sudden drop beyond a distance of 12 metres is
12 highly relevant for the recognition of familiar people,
13 because it represents a physiological limit of the
14 human eye."
15 That's the reason. So I don't think I left
16 any uncertainty about that aspect. It is only the
17 sudden drop that represents a mechanism in the eye that
18 simply applies to all faces that you see, known or not
19 known. If the eye cannot resolve them any more, then
20 it stops, you see. Therefore, below -- the bottom part
21 of the table is simply representing situations of faces
22 that could not be resolved by the eye any more.
23 Therefore, I think it's relevant to your question. It
24 is within the limitation that I have expressed.
25 Q. But, Professor, when you speak of
1identification of a face, it is identification in
2 relation to what reference system? What does that
3 student have to recognise? It is obviously my fault
4 that I have misunderstood you; you have probably
5 expressed yourself very well.
6 A. In this experiment, the subject sees a face
7 for about half a minute. Immediately thereafter, so
8 with zero seconds interval, he sees a line-up and has
9 to indicate which person in the line-up is the same as
10 the face he has observed for about half a minute. And
11 what you see is that. If you see a face -- at 20
12 metres, for instance -- for half a minute, you have
13 observed it as well as you could for half a minute.
14 Immediately thereafter, you see that face again, but
15 surrounded by some other faces, and you have to
16 indicate who was it that I saw, that for instance, at
17 an illumination level of 3.000, they are doing it about
18 five times correct against one time wrong, whereas if
19 it's 12 metres, they do it 90 times correct versus one
21 That's a huge difference. It's an enormous
22 step, an enormous loss of performance, and that loss of
23 performance is related to the fact that the eye, during
24 the first observation of half a minute, simply could
25 not see the details in that face.
1Q. Thank you for this clarification. However, I
2 have a further question. In this experiment, the
3 subject, the student, did he necessarily have to give
4 an answer, or could he have doubts or incertitude?
5 Could the student say, "I don't know"?
6 A. Yeah, definitely. The experience is that
7 very rarely subjects do that, I must say.
8 If I may add something, it's always clear
9 that an experiment is not exactly the same as being in
10 a war. If you are asked about details of the
11 experiment, we will always hit, of course, the fact
12 that an experiment is somewhat artificial and that you
13 cannot create conditions of war in an experiment. For
14 some topics, like studying emotions, that is, of
15 course, highly relevant because if you cannot recreate
16 the correct emotions, then the experiment is
17 worthless. But here we are dealing with, say, a
18 biological property of the eye, in which I feel that
19 exactly creating all sorts of conditions that are
20 present in war is not necessary. What is necessary is
21 recreating the biological conditions.
22 Exactly like when you go to an optician, he
23 presents you some letters to see whether you can see at
24 a long distance. And then, if you take the glasses
25 that he prescribed, you go to drive your car, you will
1not meet any letters any more, and still the glasses
2 will work, because we're dealing with a biological
3 mechanism that can be tested by letters, although you
4 want to apply it on the highway.
5 In the same manner, the reasoning applies --
6 at least to my mind -- that we present people with
7 faces in a somewhat experimental condition, to test
8 where the limit is that the eye can resolve. That
9 limit will exist in wartime conditions equally well,
10 because it's a biological piece of information.
11 Q. And a last question regarding this table that
12 you have submitted to us. Do I read it well by saying
13 that at 3.000 lux, the ratio is below 1; when talking
14 of a distance of 40 metres, it is 0,8; and at
15 2 luxes, which means very bad lighting, and still at a
16 distance of 40 metres, the ratio is 4 to 1?
17 A. Yeah, you're right. And that illustrates, in
18 a nice way, that the eye is connected to the brain.
19 Since these numbers are ratios, there are two ways in
20 which they can go down. One is that the upper part is
21 going down or the lower part is going up. The lower
22 part going up means false-alarm rates go up. Now, what
23 happens in the 3.000 column is not only that the
24 correct identifications go down, but also that the
25 false alarms are going up, because people tend not to
1be so cautious when there is a lot of light, because
2 they sort of have the feeling -- "There was lots of
3 light. I had half a minute to look at this. It is
4 rather silly for me not to recognise this face."
5 So they have an inclination to give a
6 response, instead of restraining themselves, as you
7 have suggested is also an option. With 2 lux, they
8 realise, "It's not so strange if I don't know the
9 answer. The experimenter will not think I'm stupid if
10 I say I don't know, because it's rather logical that I
11 don't know."
12 So at 2 lux, they don't make as many false
13 alarms. And that piece of information is, of course,
14 highly relevant for you, because what the Court has to
15 decide is: This recognition that is presented in
16 evidence, is that a hit, is that a correct
17 identification, or may it be a false alarm? And what
18 you should realise, that under daylight conditions,
19 people tend to make false alarms. That's what I'm --
20 because these are conditions that, to themselves,
21 present good viewing conditions, so they are prepared
22 to make a response. That's the danger of daylight
23 conditions, and that's why you have this difference.
24 I'm sorry it is so complicated, but in fact,
25 if you look at a simple thing like a recognition,
1rather soon you realise it's a complicated process. It
2 has to do with the tendency to believe that you are in
3 good viewing conditions and therefore it's not
4 illogical for you to state firmly that you have
5 recognised someone.
6 Q. What I'm having difficulty with, Professor,
7 is that, for reasons that are certainly justified, you
8 have two series of considerations. First, the
9 physiological performance of the human eye, and,
10 secondly, the interference of the brain, memory,
11 feelings, the psychological interference. I must admit
12 that that is probably my own problem, that I'm
13 sometimes having difficulty making a distinction
14 between the two. I'm still surprised to see that there
15 are far more errors, or false alarms, as you say, under
16 conditions of perfect illumination of 3.000 lux, than
17 with a very poor lighting of 2 luxes and at the same
19 I find this paradoxical, and I'm wondering
20 whether psychological interferences are a sufficient
21 explanation, because these two different illuminations,
22 the eye physiology being affected by bad visibility, as
23 everyone knows.
24 A. I think I must excuse myself, because I did
25 not anticipate that you would be interested in such a
1thorough discussion of these data, because then, of
2 course, I would have supplied the complete
4 As you see, this is Table 7. There are
5 tables which have separate representations of the hits
6 and of the false alarms, so that you can exactly follow
7 why these ratios change, and then you can see that the
8 effect that you call paradoxical, indeed, is caused by
9 the fact that people make false alarms under good
10 viewing conditions and far less false alarms under
11 difficult viewing conditions.
12 You can see the same effect if you look at
13 the difference between 3 metres and 5 metres. What you
14 see at 3 metres, for 3.000 lux, you see that's not the
15 best performance. It becomes slightly better at
16 5 metres, which is paradoxical. But that's not related
17 to the hits; it's again related to the false alarm.
18 Because if you saw a person at 3 metres, and then you
19 say afterwards, "I don't recognise this person," then
20 you look rather silly. So subjects have a tendency to
21 at least point at someone, because they realise that
22 the viewing conditions were perfect. And again, since
23 the eye cannot be separated from the brain, we will
24 always have such effects, but the sudden drop between
25 12 and 20 metres is really caused by a sudden decrease
1of the hits.
2 So if you're interested, and if it's relevant
3 for the proceedings of your Court, of course I would
4 supply the complete publication so that you possess all
5 the information that there is in it, although, in a
6 sense, I would also like to warn you a little bit that
7 what I'm saying about the eye is of course not only
8 based upon this one publication. We know the density
9 of cones in the retina perfectly well; there is simply
10 no discussion. Any basic textbook will give you that
11 sort of information. But if it's relevant to you, I
12 would of course be glad to supply the whole
13 publication, and you can split all those effects out.
14 If you need more explanation, then later on, I would be
15 happy to return and do that for you.
16 Q. Forgive me for asking this question, but
17 since you relied quite extensively, it seems to me, on
18 your experimental findings to say that facts that have
19 to be tried by this Chamber, recognition carries a
20 serious risk of error. My role as Prosecutor finds
21 this to be a very important point in the trial; not the
22 only one, but very important, still. As a member of
23 the Prosecution, it is up to me to see whether this
24 experiment, and this experimental knowledge that you
25 are conveying to us, allow us to read and understand
1the reality facing this Trial Chamber.
2 In view of that, I am asking you whether --
3 don't you think that the relief of the face which is
4 known, or which is to be recognised, the face in
5 reality, such as it is, is it not an important element
6 to be taken into consideration, and that this
7 experiment, which you have conveyed to us, did not take
8 that into account at all?
9 A. Yeah, sure, there's a number of things to be
10 said about that issue. The experiment is based upon,
11 say, a whole variety of faces, not on one face, so the
12 data are telling you something about recognising human
13 faces in general. If there's one particular face with
14 very outstanding features, then of course -- and you
15 have a reason to believe that everything would be
16 different for that particular face -- then you should
17 do experiments with subjects and that particular face
18 specifically, which can be done, of course.
19 What I have done, however, is describe what
20 would happen, and what the risks are, if we are talking
21 about a face that is just a normal human face, with not
22 such distinctive features that you would say for this
23 particular face, everything would be different. And I
24 have found no information, in the documentation that I
25 have received, that we're dealing with a very specific,
1remarkable face with outstanding features, and I have
2 no way to make a judgment about that. I have not even
3 seen a picture of the person that was seen, so I have
4 no judgment about it. But if you have reason to
5 believe that everything would be different for this
6 particular face, I think then you should request a
7 specific study for that face.
8 However, I still would like to warn you that
9 at 60 metres, if you think that a specific face would
10 be highly and reliably recognisable at 60 metres, it
11 should be really a remarkably different face, with
12 large details that are different from normal. To give
13 you an example, if a person is a cyclop, has one eye in
14 the middle of the front, that can be seen at 60 metres,
15 rather obviously. But a rather big nose would already
16 be difficult, because even big noses are not so big, so
17 it should be a remarkably big nose.
18 But I have simply no information about the
19 specific face that we are discussing here. To make any
20 judgment about that, I think it's your judgment to see
21 whether there is reason to request a specific study, or
22 at least reject this study. It's up to you.
23 Q. Professor, I wasn't really speaking about a
24 face with recognisable features, and still less a
25 monster. My question is: Is it really the same thing
1to look at a photograph and to look at a real person at
2 the same distance? Is it quite the same thing?
3 A. Yeah, of course, we have studied that before
4 running such an experiment, so one part -- also
5 reported in this publication, I think, if you would
6 have a complete copy -- is that first, of course, we
7 made a comparison of seeing the real person and seeing
8 a photograph of that person, under these conditions, to
9 see whether that would not make a difference. Of
10 course, the advantage of using photographs instead of
11 real persons and presenting real line-ups all the time,
12 instead of photograph line-ups, the advantage is so big
13 that if you can do that, and you understand that this
14 is a table that represents six, seven times nine
15 experiments, in each cell is one experiment, so it's a
16 huge study. So if you can do that with photographs,
17 it's such an advantage that you would always do it, if
18 its possible.
19 Therefore we ran a pilot study to see whether
20 the results would be any different if you used real
21 faces, real persons, instead of photographs. The
22 results were equal, so I don't think that is a
23 particular problem.
24 Q. For example, the context in which a face is
25 to be recognised, can the background have any effect?
1Is it the same to recognise a face with a white
2 background or with a forest in the background? Does
3 the background play a role?
4 A. Oh, definitely, definitely. Here we have
5 used backgrounds with optimal contrasts, so that's the
6 best possibility of recognising the faces. It's very
7 easy to make it more difficult. For instance, say one
8 important feature of people is their hairstyle, and if
9 you use a background of the same colour as the hair, it
10 becomes very difficult to recognise the hairstyle, and
11 then one important feature is lost.
12 These data reflect optimal conditions in
13 which things like the hairstyle, for instance, can be
14 optimally seen, so you can easily make it much more
15 difficult and the results get worse.
16 Since I have simply no information about the
17 background against which, say, in your case the face
18 was seen, you really need a careful reconstruction,
19 because if people are standing in front of a house, if
20 they stand in front of the white wall of the house,
21 it's totally different than if they stand in front of
22 the black window of the house. Still, the distance
23 would be 50 centimetres to the right or to the left.
24 So I have not even tried to reconstruct for
25 myself what the situation would be. I've only looked
1at let's assume that it's optimal. Then still we've
2 got this problem.
3 Q. Thank you. I should like to go back to the
4 effect of fear and danger that you referred to.
5 You said, if I understood you correctly, that
6 a situation of fear and danger can limit the field of
7 observation, while at the same time increasing the
8 attention, the focusing of that subject on that field
9 of vision.
10 I wanted to ask you, and I think you already
11 have answered up to a point --
12 MR. RADOVIC: Mr. President, my client would
13 like to be excused for a moment, if he may.
14 JUDGE CASSESE: Mr. Terrier, you may
16 MR. TERRIER:
17 Q. I wanted to ask you to tell us whether this
18 effect which you have explained, that of fear and
19 danger, is valid for all individuals, for all persons,
20 or, on the other hand, are certain persons prone to
21 lose all their capacity of observation in a situation
22 of fear and danger?
23 A. Well, to begin with, I think I have clearly
24 stated that on the matter of fear, I have no opinion on
25 what effect it could have had in this particular case.
1It could have improved the observation, and it could
2 have worsened the situation. I have simply no idea,
3 because it's very difficult to predict where the
4 witness would look.
5 Now, individual differences are mostly
6 influencing the question whether, in a particular
7 situation, a person will have fear, because if you are
8 used to a situation, you might have less fear than if
9 that situation is completely new to you. So individual
10 differences are related mostly to in which situations
11 will the fear occur. But given the same amounts of
12 fear in various people, the effects will be more or
13 less the same.
14 So the question in this case would be, "How
15 much fear will there be in this particular witness,"
16 and I have no way of knowing that. I don't even know
17 the witness. The question is not so much, "And if
18 there was fear, would there be the same effect as in
19 other people," because these effects of fear are rather
20 universal. The biggest difference with respect to
21 people is some have fear and some don't.
22 Q. I understand what you are saying, but I
23 should like to respectfully note that they are not
24 responsive to my question.
25 To go back to the facts that we have to
1judge, this was indisputably a situation of danger,
2 because the group of people who were being shot at were
3 escaping, about to flee, and they were exposed to
4 threat. None of them were armed. They were all
5 civilians. Some were women, others were children. So
6 without any doubt, we're facing a situation of danger.
7 Let us not speak of fear. Let us just focus
8 on the question whether this situation of danger, which
9 is undisputed, what effect it could have had on the
10 capacity of observation and attention of those people,
11 and did it differ depending on the personality of
12 each? Of course, I'm not asking you to analyse the
13 individual effect, but could there have been a
15 A. The difference, if you assume the same amount
16 of danger and therefore -- which is not a necessity,
17 but let's just, for the sake of argument, assume the
18 same amount of fear in these people, then there is
19 still the question, "What will they focus on?" One
20 person may focus on the arms that are pointed at them,
21 and other people may focus on the faces behind those
22 arms, which is a different thing. Others may even
23 focus on totally different areas where they expect that
24 some other danger will come from. So the differences
25 with respect to how people would react, given that they
1have the same amount of fear, in my opinion would in
2 the first place be on what will they focus on.
3 To give a very simple example, it has nothing
4 to do with emotions and it happens to me all the time,
5 if I'm visiting other people and I come back, my wife
6 always knows what the other women were wearing and I
7 don't. I've seen the same, but I've not focused on the
8 same. There is some difference between men and women
9 with respect to what they pay attention to.
10 Now, obviously since we're here, we're
11 talking about men, women and children. They may pay
12 attention to different things, and then the fear, that
13 will have a remarkable effect, because paying attention
14 to the one thing rather soon means that you did not pay
15 attention to the other things.
16 So, indeed, you're quite right, there may be
17 huge differences as to what they paid attention to.
18 The only thing I want to stress is that for me, as an
19 expert, it's not a subject I can really tell you much
20 about because I have no basis for deciding whether the
21 witness in this case paid a lot of attention to that
22 face or not. It's quite possible that he paid a lot of
23 attention to that face. It's also possible that he
24 didn't. I have no way of knowing. That's not a
25 question, I think, that you can pose to an expert who
1was not there.
2 Q. Yes. But, Professor, don't we have there the
3 answer to the question number 6 posed to you by
4 Mr. Krajina, why other people in the same group did not
5 recognise the face in question? You said that it was
6 due to the distance. Couldn't the answer simply be
7 because other people may have been looking at something
8 else, their attention may have been drawn to some other
10 A. You're quite right. It's quite possible that
11 these other people were not looking at this face. But
12 what I wanted to say is that even if they had
13 concentrated on this face, still the distance of 60
14 metres would have made it rather unlikely that they
15 would have recognised anyone.
16 Maybe it's a bad habit of scientists, but if
17 there's a simple answer that makes it not necessary to
18 go into the more difficult things, then we are always
19 quite satisfied and say, "Well, we take the simplest
20 argument, and that relieves us of going to a far more
21 difficult thing about which I can tell you very little.
22 So why would I speculate on the more difficult thing if
23 I can tell you something that's rather reliable on the
24 simple question of distance?"
25 So you're quite right, and if you want to
1make that speculation, I'm the last person to stop
2 you. I can only say I have no way of knowing where
3 these people looked.
4 Q. I will not engage in any kind of speculation,
5 Professor. I'm just trying to take advantage, from
6 your experience and your knowledge, to be able to
7 better interpret the extremely complicated real
8 situation that this Trial Chamber has to judge.
9 Now to go to another question, the question
10 of the degree of familiarity between the person who is
11 doing the observation and the person to be recognised.
12 Wouldn't a high degree of familiarity
13 facilitate, at a distance of 40 or 50 or 60 metres, the
14 recognition of the face?
15 A. Well, I would say beyond a certain level of
16 familiarity, the differences are not so important
17 anymore. There are large numbers of people whom we
18 know and whom we will recognise in half a second, and
19 they don't have to be more familiar to be recognised by
20 us. So degrees of familiarity, at least they have not
21 been studied, so on the basis of scientific research,
22 there's very little to say about it.
23 But I think I have to come back to the same
24 statement again. Even if there is a high degree of
25 familiarity, beyond a certain distance you're going to
1make mistakes. In the end, you may even think that at
2 a certain distance that person is your wife, and she
3 isn't. Some distances are simply too long for reliable
5 Another problem is, of course, that -- but I
6 don't want to complicate the matter, of course -- we're
7 talking here about a familiar person in a rather
8 unfamiliar situation, and I don't know much about, and
9 I've also written that in my letter, about, for
10 instance, any head gear the person was wearing or
11 anything unusual about the person whom you knew under
12 different conditions, so I find it very hard to address
13 the issue of familiarity at all without much more
14 information about that exact situation.
15 Therefore, again I would come back to the
16 essential statement that 60 metres is simply
17 prohibitive for reliable identifications anyway.
18 Q. My question was the following: You told us
19 that at 60 metres, identification is not impossible but
20 it carries a risk of error. My question was whether a
21 considerable degree of familiarity that we are going to
22 suppose between the subject and the witness does not
23 reduce that risk of error.
24 A. Not necessarily, and we have to go back to
25 the problem of hits and false alarms.
1High familiarity, in the first place, means
2 that it is a response that is rather on the front of
3 your mind. It's one of the responses you would first
4 make rather than another response, which means that
5 familiarity may increase the number of hits, which
6 means if it is really the person you think it is, you
7 are more likely to identify him, but if it's not him,
8 are you more likely to make a false alarm, and
9 therefore not necessarily the ratio of the two will go
11 But this is a theoretical answer, of course.
12 I understand that. But there is simply no research in
13 which, say, degrees of familiarity are used in an
14 experiment to see what exactly hits and false alarms
15 will do. I will only warn you not to assume that just
16 for logical reasons, say, the numbers should go up. It
17 could go down as well.
18 Q. Professor, you told us and you have written
19 in your report that the pertinent features that the eye
20 has to resolve to be able to make recognition are
21 typically 0,5 centimetres, and you added that the
22 smallest details which can be resolved by the human eye
23 at a distance of 60 metres are of the order of two
24 centimetres, and therefore we are facing a
25 physiological difficulty there. I would like to ask
1you, and I address you as a psychologist and your
2 professional experience in the field, what are the
3 features of a face which need to be seen and recognised
4 to permit identification, and do all features in the
5 face contribute equally to an identification?
6 JUDGE MAY: I seem to remember we've been
7 through this. We had discussions of the nose and that
8 sort of thing. I'm just wondering how helpful this is
9 to the Chamber, to go into all this detail.
10 MR. TERRIER: My question, Your Honour, was
11 the following: The expert has told us that details of
12 a certain size need to be identified. My question was,
13 "Which are the features and characteristics of a face
14 that need to be recognised, and what should their size
15 be for that identification to be possible?" It seems
16 to me, and maybe I'm wrong, maybe I'm going beyond my
17 duties here, but it seems to me that I can contribute,
18 to a certain degree, to a better understanding of this
19 matter by Your Honours.
20 I think that this is a question that can be
21 usefully put to the witness, but of course if you
22 consider it quite useless, I will withdraw it.
23 JUDGE MAY: It's a matter for you and I'm not
24 going to stop you, but please allow some common sense
25 in the matter.
1MR. TERRIER: Very well, Your Honour.
2 Q. Professor, as a psychologist, could you tell
3 us which are the facial features that need to be
4 identified for recognition to be possible and whether
5 these features, in themselves, contribute to an
7 A. There is a lot of misunderstanding about what
8 is important to recognise a face, because people tend
9 to believe that it is the eye or the nose or the mouth
10 or something, whereas in fact it's the relationships
11 between those things, the distance between things, the
12 distance between the eyes, the distance of the eyes
13 related to the size of your head and so on, so it's a
14 matter of perceiving the relationships and not
15 perceiving, say, eyes or noses. A slight change in
16 relationships, placement of things, makes things
17 totally different.
18 So it's very hard to say, "Well, I saw the
19 eyes. That's enough," or, "I saw the nose. Isn't that
20 enough?" It's the relationship between things that
21 matters most, that makes it so intangible to describe.
22 If you ask a witness, "Well, you recognised him. How
23 did you recognise him, then," or, "What did you
24 recognise then?" Sometimes witnesses answer those
25 questions, "I recognised the eyes," or, "I recognised
1the nose," but, in fact, witnesses don't know what they
2 need to recognise a face because it's relationships
3 between things in the face, and that's rather
4 abstract. That's where half centimetres matter.
5 Q. Let me put my last question to you,
6 Professor, and that is related to suggestion.
7 You said that the recognition of a person
8 that one knows from before is an immediate phenomenon,
9 and a question put to you by Mr. Krajina, you said that
10 suggestion plays a role, relating this to the fact that
11 the witness did not immediately give to his
12 interlocutors the name of the person that he
14 In the circumstances that you familiarised
15 yourself with, the circumstances of the time and place,
16 does it seem really unusual that the witness did not
17 immediately inform the people around him of the name of
18 the person that he had recognised?
19 A. Of course, you're quite right. It would have
20 helped a lot if I would have known that immediately he
21 said or cried, "It's so and so," because that would
22 mean there's an immediate recognition, and after that,
23 there is no inference of suggestion anymore because the
24 recognition is made, period.
25 Now, I am in a situation in which I was told
1that he reported it much later. On that basis, I
2 cannot decide whether he recognised immediately or
3 not. I only know he did not report it immediately.
4 It's impossible for me to decide whether he recognised
5 immediately but had good reasons not to give away his
6 information or he recognised not immediately but
7 gradually became aware of what he had seen. I cannot
8 make that distinction on the basis of what is provided
9 to me, and it's a highly-relevant question and I think
10 you have to answer it. But on the basis of the
11 information I was given, I can't answer it.
12 Q. Therefore, the silence of the witness for a
13 certain period of time, in itself, doesn't necessarily
14 mean that he was under any suggestion?
15 A. No. It opens the possibility. It has to be
16 sorted out, what happened.
17 MR. TERRIER: Thank you very much, Professor,
18 for having answered my questions.
19 I have no further questions, Mr. President.
20 JUDGE CASSESE: Thank you, Mr. Terrier.
21 Counsel Par?
22 MR. PAR: No more questions, Mr. President.
23 JUDGE CASSESE: Thank you.
24 Any questions? I'm afraid I have a short
1Professor Wagenaar, I have realised that you
2 have focused on the face of the person to be
3 recognised, and at one point, I took some notes, you
4 played down movement and posture. I wonder whether
5 this is because you were under the influence of your
6 own study, which was about faces and faces on
7 photographs, because speaking as a layman, as a man on
8 the street and of my own experience as somebody who is
9 used to walking not here but in another place very
10 similar to the country we are talking about, where
11 there are hills and woods and so on, I can say that
12 very often you can see from a distance, say even 50,
13 60, 70 metres, people whose face is not very clear, but
14 then one may pay attention to the fact whether the
15 person is short, is tall, is bald or has a lot of hair,
16 but even more important, were they slim or fat or
17 burly, so it is this combination which may prompt me to
18 say, "Aha, well the face is not so very clear, but his
19 whole body does match this name," of course on the
20 assumption that this person is familiar to me, a person
21 whom I have seen for ten years, for instance, in that
22 particular area. So this is what happens to me, for
23 instance, when I walk in Tuscany sometimes and I see
24 people, and as I say, because of this combination of
25 various elements, I am in a position to recognise this
2 So my question is: Is it proper and correct
3 to also emphasise the role of the other elements which,
4 together with the face, may allow you, enable you, to
5 say, "Yes, this is the man whom I know and he is there
6 up on the hill, and I can see him even if he's in a
7 wood, in a clearing in a wood, but I can see him fairly
9 A. Of course, you're quite right, Your Honour,
10 that such facts exist. But I focused, I hope, not so
11 much on the studies I did, but on the situation as it
12 was presented to me, and the following features are
13 important: There are a number of people standing there
14 at a distance of 60 metres. Now, to decide what their
15 size is, you need some sort of reference. It's not
16 obvious to me that a good reference point was available
17 so that you could see whether they were short or tall.
18 The size of people is very hard to distinguish if you
19 have no reference point.
20 The following point is that I have no
21 information that the size of the person who was
22 observed is remarkable in any way, which means that
23 even if you perceive the size correctly, that doesn't
24 mean that it definitely must be that one person,
25 because if many people have the same size, then still
1it doesn't help you so much to perceive size correctly
2 with the aid of reference points.
3 The same as for posture. You're quite right,
4 some people are highly recognisable because of their
5 posture, because they are fat or slim or crooked or
6 whatever. The question is if someone is just normal,
7 falls on the average, how could you recognise such a
8 person on the basis of posture? And experimental data
9 shows that that is very, very difficult.
10 The experiments run, more or less, as
11 follows: You make a comparison of recognition scores
12 in a number of situations. One is life, moving. One
13 is life, stationary, so movement is excluded. The next
14 is on television, moving. Then on television,
15 stationary. Then on a photograph, total body, and
16 finally on the photograph, only face. What you see, if
17 you compare those conditions, that the differences are
18 very small. The contribution of movement, posture,
19 size, are really very small compared to what you can
20 tell from a face.
21 Now, a further condition is here, that I was
22 told he looked in a moment, and the question is how
23 much movement of people can you see in a moment if
24 you're talking about one fixation, and that's what I
25 have reported in my letter. In one fixation, you can't
1see any movement, you just see a still picture, and
2 then there is very little to tell about movement. So I
3 have not concentrated about these elements of what I
4 was to say, because the face is so much more important
5 than the other things in this situation that I think
6 perceiving the face would be decisive.
7 JUDGE CASSESE: Thank you. Thank you so
9 I assume there is no objection to the witness
10 being released.
11 Professor Wagenaar, we are most grateful to
12 you for testifying in court today, and you may now be
14 Before we adjourn, let me simply remind the
15 parties that we will reconvene on the 21st of June for
16 one week. We will then skip the following week, and
17 then we will resume our proceedings on the 5th of July
18 until the 23rd of July, just as a reminder.
19 So the hearing is adjourned.
20 (The witness withdrew)
21 --- Whereupon the hearing adjourned at
22 11.35 a.m., to be reconvened on
23 Monday, the 21st day of June, 1999,
24 at 9.00 a.m.