WITNESS TESTIMONY: Can it be believed?

In court, witnesses are asked to give evidence about events which may constitute a criminal offence, or may form part of a series of events concerning a civil dispute. Judges and juries must then assess the reliability of witnesses’ evidence.

Eyewitness identification evidence is the leading cause of wrongful conviction around the world. Of the more than 200 people exonerated by way of DNA evidence in the US, over 75% were wrongfully convicted on the basis of erroneous eyewitness identification evidence. Some of those convicted on the basis of eyewitness testimony served many years in prison before it was established that they were innocent all along.

In England, the Criminal Law Review Committee, writing in 1971, stated that cases of mistaken identification ‘constitute by far the greatest cause of actual or possible wrong convictions". Yet despite substantial anecdotal and scientific support for the proposition that eyewitness testimony is often unreliable, it is held in high regard by jurors in criminal trials, even when "far outweighed by evidence of innocence.’ In the words of former US Supreme Court Justice William J. Brennan, there is "nothing more convincing to a jury than a live human being who takes the stand, points a finger at the defendant, and says 'That's the one!

When I was practicing law in criminal court, I was well aware of the danger of a witness pointing a finger at my client because the witness presumed that if my client was sitting next to me, he must be the person who committed the crime.

In one particular case I was handing, I decided to see if the witness would tell the truth under oath based on what he presumed was the defendant in my client’s case. Prior to the trial, I told my client not to talk to me in the courthouse and that when his case was called, he was to remain in the body of the courtroom unless the judge ordered otherwise. Before the court was called to order and everyone was in the hallway, my client pointed to the witness and then I began talking to a stranger about my client’s case within earshot of the witness. I gave the impression to the witness that I was talking to the man the witness was going to testify against. When my client’s case was called, I asked the court to permit my client to remain in the body of the court. Then I asked the witness to identify the man he claimed assaulted him. The witness pointed to the man I had been talking to and whom I sat next to during the previous trials. The charge against my client was dismissed.

There are no simple or straightforward answers to questions about the reliability of witness testimony. While much of the research in relation to eyewitness testimony, children’s evidence and adults’ memories of traumatic events has focused on the limitations of memory.

First, I would like to tell you something about memories.

Memories are not permanently stored as if recorded on tape, unaltered, to be played back some time later as an exact recording of the event. Many times, they are simply erased. For example; how many times have you awoke after just having a dream and within minutes, you can’t remember what you dreamed about. Can you remember every meal you ever had? Some meals you will never forget. I remember the greatest banquet I ever ate at. It took place in the backyard of the Minister of Justice for Venezuela in Caracas in September 1980 and I also remember the last meal I had with my mother before she died in Olympia, Washington, USA. I remember other meals but for the most part, I forget almost all of them because other than keeping me alive and giving me satisfaction with respect to my craving for something to eat, my meals didn’t play an important role in my life.

Our memories inolve three stages: acquisition, storage and recall. The processes involved with each stage influence how accurately and completely any witnessed event will later be recalled.

Every thing we experience with our five senses and I might add, our dreams also, becomes part of the acquisition stage. That is when information is encoded in memory. This involves transferring the information from “short-term” (working memory which holds information for a few seconds) to “long-term” (more permanent) memory.

Everything we experience relating to perception, attention and understanding, including the stress or shock of an event or a person’s expectations of what will happen, may influence what information is encoded in memory and how well is it encoded.

The retention stage is the period of time that passes between an event and the eventual recollection of a particular piece of information. Once information enters a witness’ memory, it may reside there for a period of time before the witness attempts to retrieve it.

Psychological research indicates that stored information is malleable and subject to change and distortion during this retention stage. Memories may change simply as a function of time, particularly following very long delays. Also, the relationship between memory and the retention interval is a ‘negatively decelerating’ one. This means memory retention drops off rapidly at first and then the decay is much more gradual.

Memories may also change as a result of similar intervening experiences, rehearsal of the event (for instance, thinking and talking about it), and exposure to other information about the event. Many factors which affect encoding also affect the retention stage.

Let me give you an example as to how memories play tricks on you. Many years ago, I heard a piano piece I really liked and it naturally was retained in my memory banks by me. It dropped off shortly after that and gradualy it was buried deep in all the other memories I had. Then years later when I was in the mood to compose some more serious piano music, this piece emerged from deep inside my past memories and unknown to me, I began playing it as if it was one of my own compositions. As the weeks passed, I made some changes but the theme was the same the one I had heard many years previous. After I performed it in front of some people, one of them said, “That piece sounds familiar. Have you recorded it somewhere?” I told him that many composers inadvertentlty compose a piece that has some remnents of another piece they heard. For example, the American song America is also the same song as God Save Our Queen although the only difference are the words. I figure that perhaps I had heard a similar piece to my own composition and incorporated some of it into my own composition. Then one day while listening to the radio, I heard the entire piece that I thought was my own being played by an orchastra. It had been written by a famous composer before I was even born. If I hadn’t heard that peiece on the radio, I would have sworn that my composition was genuinely mine. I still play that piece but I don’t claim that it is one of my compositions.

The retrieval stage, is that period in which a person recalls the information about the event. Recall is influenced by the cues available to retrieve the memory; for example, as provided by questions, or physical cues such as photographs or a reinstatement of the original context of the event. Recall is also affected by the social context in which the person is asked to recall the information. Strangely enough, smells is a sure way of retrieving memories.

Forgetting is, failure to retrieve information from our memory, which is brought about by: 1. failure to store information correctly; 2. displacement of information; 3. the memory trace has faded away or decayed with the passage of time; 4. interference from later input which sounded similar and impacted negatively on the short-term memory or information which is semantically similar and interfered with information stored in the long-term memory; 5. lack of appropriate retrieval cues.

Blocking memories is not something we can do consciously. Some people have terrible things happen to them and their memories of the events are subconsciously blocked as a means of protecting the human mind from suffering from serious depression or fear. Generally, if the event is traumatic enough, it is impossible or at least almost impossible to retrieve it. That can be a blessing but it can certainly himder a victim’s memory when the memory of the event is necessary when giving evidence against the criminal who brought the event about in the first place. Thias doesn’t always happen of course. The young woman whose arms were chopped off by a rapist remembered who he was and testified against him at his trial.

Hypnosis is an effective way to assist someone to recoverlost memories. I won’t deal with hypnosis as a tool for recoverning lost memories as I have dealt with that issue in a previous essay in my blog.

The accuracy and comprehensiveness of any person’s recall, depends on factors such as the personal significance of the event, the emotive content of the event, the time lapsed since the event, the occurrence of other related events, why and by whom the person is asked to recall their memories, and the kinds of retrieval cues provided at the time of recall.

‘Implicit memory’ is memory which operates at an unconscious level. They are what has an effect on our habits, skills, emotions and reflexive actions. That kind of memory is not available for conscious verbal recall but may impact on a person’s behaviour.

As examples, consider the following. You don’t step into a bath without first making sure that the water isn’t too hot. The same goes for drinking coffee. We have all probably experienced sometime in our lives, stepping into hot water or drinking a hot drink. That kind of memory become fixed in our memory banks and although we can’t retrieve it at will, it is there as a hidden warning to tell us to be very careful when stepping into a bathtub or drinking a hot drink. Mind you, there may very well be incidents in our lives that we will never forget that have an effect on our habits. I am thinking of the silly woman in the United States who placed a scalding hot cup of coffee between her legs when she put her car in motion. She will never forget what happened next and will not only consciously not do that again, but unconsciously, she will take great care before she puts the coffee to her lips.

‘Explicit’ (or recollective) memory is memory which is accessible to the consciousness. These memories may be recalled consciously by merely thinking about the events that occurred. What I described about what that woman did with her cup of coffee is an example of explicit memory. What I described in this essay about some of the meals I have had in my past is a good example.

There are two kinds of explicit memory: semantic memory and episodic memory. Semantic memory refers to our general knowledge of the world, of the sort that may be recorded in an encyclopaedia or a dictionary. Episodic memory refers to the memory for events that involve the individual, of the sort that may be recorded in a personal diary, that happen at a specific time in a particular place. These are the most fragile of memories and are probably not fully formed until a child has developed a concept of self and the necessary cognitive skills.

Autobiographical memory system refers to the system by which we organize the episodic memories that make up our personal histories. They are significant memories that are related to our concept of ourselves in some way. This system is dependent on the
development of cognitive skills, particularly language. Even in adulthood our autobiographical memory is likely to be patchy and subject to distortions, the more so the more distant the memory.

I am currently working on my memoirs so it follows that I have to make use of my explicit memories however on occasion, someone has triggered a memory from my unconscious memory bank so it suddenly became an explicit memory.

The influence of the passage of time on one's memory in terms of sharpening and leveling, has an effect on that memory and as such, may alter the original perception. As time passes the, the critical aspects of the originally perceived situation becomes exaggerated or sharpened out of proportion to their significance in the original perception. This is known as ‘sharpening’. Similarly, memory for less critical aspects of the original perception becomes diminished below the proportion it help in the original perception. This is known as ‘leveling’. These two effects continue to occur from the time of the perception and the subsequent retrieval of that information. Insofar as recollection of a face is concerned, time causes the memory to distort (sharpen) and highlight certain features and discard (level) or minimize less salient features.

Memories are capable of being fused. That is, one perception may become fused in the mind's eye with another. Some behavioral scientists call this ‘unconscious transfer’. Thus, if an eyewitness to a crime subsequently sees a person who looks familiar, this familiarity maybe interpreted by the memory as relating to the crime, even though the actual contact between the witness and the person identified may have occurred innocently prior to the criminal event. In effect the two memories of people or objects at two different times bleed into each other, with the result that the memory confuses one for the other. Mistaken identification of a person as a wrongdoer may result because the person looked familiar.

Eyewitness identification depends on witness candor. Most faulty identification evidence is the result of honest mistake , rather than deliberate misidentification. The danger in such good faith mistaken identification evidence is that it is sincere. Many people who were wrongly identified and imprisoned for long periods of time were found guilty based on the testimony of honest citizens who simply made a mistake in wrongfully identifying them.

Sometimes a witness to a crime has forgotten all about the event because so many years have passed but when an investigator speaks to the witness about the event, the memories of the event are triggered into action and they become explicit memories. However, sometimes minute details which were buried as a non-explicit memories are buried so deep, they remain their permanently.

Courts, lawyers and police officers are now aware of the ability of third parties to introduce false memories to witnesses. For this reason, lawyers closely question witnesses regarding the accuracy of their memories and about any possible ‘assistance’ from others in the formation of their present memories. Suggestion by those asking the questions about what a witness had seen or heard can be created intentionally or unintentionally in many subtle ways.

For example, it is not unheard of for a police investigator to prompt a witness into ‘remembering’ and event that the witness actually didn’t see. For example, suppose the criminal was wearing a black sweater and the witness thought it was a dark blue sweater. The investigator then asks “Could it have actually been a black sweater?” The witness thinks that the investigator probably knows what the colour of the sweater is and then replies, “Yeah. That’s what it was. It was a black sweater.”

Sometimes a lawyer or a prosecutor will cause a witness to turn his own testimony into shambles. I remember listenting to a witness state a particular time an event occurred. Then the prosecutor suggested that the event took place a half hour later. The witness, wanting to please the prosecutor agreed with the time that the prosecutor suggested. As it turned out, the time originally stated by the witness was the correct one. I am not suggesting that the prosecutor was trying to frame the defendant. What he was doing however was trying to get the witness to testify with respect to the time the event took place in the same way that a previous witness had testified. The prosecutor was wrong in doing this because he was putting words in his witness’ mouth and since it was his witness, he wasn’t by law, permitted to do this.

The process of interpretation occurs at the very formation of memory—thus introducing distortion from the beginning. Furthermore, witnesses can distort their own memories without the help of examiners, police officers or lawyers. Rarely do we tell a story or recount events without a purpose. Every act of telling and retelling is tailored to a particular listener; we would not expect someone to listen to every detail of our morning commute, so we edit out extraneous material. The act of telling a story adds another layer of distortion, which in turn affects the underlying memory of the event. This is why a fish story, which grows with each retelling, can eventually lead the teller to believe it.

I remember telling my friends a story that took place in my life when I was a small child. I believed that the event really occurred. My mother told me that the event didn’t actually happen. Where I got the idea that it happened to me, I have no idea. If my mother hadn’t corrected me on my story, I would to this day still believe that it really happened.

Once witnesses state facts in a particular way or identify a particular person as the perpetrator, they are unwilling or even unable—due to the reconstruction of their memory—to reconsider their initial understanding. When a witness identifies a person in a line-up, he is likely to identify that same person in later line-ups, even when the person identified is not the perpetrator. Memory is affected by retelling, and we rarely tell a story iexactly the same way twice. By tailoring our stories to our listeners, our bias distorts the very formation of memory—even without the introduction of misinformation by a third party.

An eyewitness to a crime is more inclined to recount, and thus remember incriminating details, when speaking to a police officer intent on solving the crime. This is also why witnesses to a crime should eright down the details of what they saw as soon after they saw the event. This way they can refresh their memories when giving testimony at a much later date. This is also why police officers should let witnesses look at the police officer’s notes prior to a trial so that the witness can refersh his or her memory of the events.

It is not necessary for a witness to lie or be coaxed by prosecutorial error to inaccurately state the facts—the mere fault of being human results in distorted memory and inaccurate testimony. Even trained observers such as law enforcement officers, can make erroneous identifications in exigencies of the moment.

Often trial judges who were former prosecutors, show only passing consideration to the dangers of eyewitness identification. This naivete is reflected when judges pass the buck to juries in the expressed belief that jurors are bred with the ability to intelligently measure identification testimony and that the good sense of those serving on juries will adequately protect the innocent accused from tragically mistaken misidentification. Of course, that is a myth.

Juries are the fact-finders, and credibility issues are to be determined by juries. The issue then arises whether juries are equipped to make these determinations. Bias creeps into memory without our knowledge or our awareness. While confidence and accuracy are generally correlated, when misleading information is given, witness confidence is often higher for the incorrect information than for the correct information. This leads many to question the competence of the average juror to determine credibility issues.

Law enforcement officers who conduct a lineup are in a position to influence the witness, particularly if the witness desires to be approved as a good citizen and/or wishes to show appreciation for the officer's efforts to solve a crime. The witness may try to pick the right person in the lineup rather than saying, I don't know because I don't remember." On occasion, police identification procedure can cause a witness to be psychologically ‘set’ to identify a particular person. The concept of ‘set’ means that, prior to a lineup, the percipient witness may be primed to a state of preparedness to receive a particular class of stimulation and to operate on that stimulus in a pre-defined manner, namely, to identify. Suppose the police provide the witness with post-event data that is mingled into the witness' recollection of the event. The witness is then set to identify someone in the lineup who displays the post-event characteristics. This is a major reason why lineups shouldn’t be done without the presence of the suspect’s lawyer being in the viewing room. Often, a lineup is done as a photo lineup. Again, the defendant’s lawyer should be present.

I remember being asked to look at a photo lineup. There were three pictures shown me. Two of them were of the suspect and the other was of a stranger. I was able to identify the suspect because I knew him from my past but showing me two pictures of the same person was highly improper.

Another inappropriate way in which a police officer will encourage a witness is to identify the suspect they have in custody is for the investigator to give the witness a headsup by saying the following; "We found some blonde hairs that we think belong to the man who attacked you. We've got a suspect. We'd like you to take a look at the guy." The suspect they have is blonde but the real rapist may have had red hair.

In some cases, the eyewitness' identification testimony is unshakable. Often there is no leverage to be gained by sustained attack on the witness' ability to perceive, recollect and/or communicate what he saw. The reason is simply the witness is telling the person questioning him or her what the witness really believes what he or she actually saw or heard even if the witness is mistaken and the witness appears as being truthful, unbiased, and without motive to falsify. Tactical considerations may suggest some other avenue of demonstrating that the identification is mistaken such as retaining the services of an expert who will explain to the court and the jurors how truthful witness can be mistaken.

Unless the eyewitness is a friend, family member or an acquaintance to the defendant, the testimony of a witness testifying what he saw a stranger do to another person is fraught with the possibility that his or her testimony is mistaken. It is for this reason that eyewitness evidence is the worst kind of evidence presented in a court trial.