The Whole Truth: But How Reliable Is Witness Evidence?

Posted by: michael  :  Category: Factors affecting Brain Health

You may be familiar with the phrase “the truth, the whole truth and nothing but the truth…”  It is used in court to swear in a witness and basically means don’t leave anything out and don’t tell lies.

No doubt most witnesses do their utmost to tell the truth but just how reliable is witness evidence and what has it got to do with the brain.

To try to find out some answers let’s start by setting up courtroom scene. In the following dialogue the prosecutor is designated as P and the witness as W.

The interaction proceeds something like this…
P to W: Please you tell us, in your own words (they always say that!) what you saw on the evening of 3rd November
W: One of the men moved forward and raised his arm.
P: Was that the defendant?
W: No
P: You told the police he hit the defendant.
W: Yes, I was sure he hit him.
P: Did you actually see him strike the defendant?
W:Not exactly, but he was very close and I’m fairly certain he did.
P: Are you certain or are you not!
W: Yes, I think I’m certain but you are getting me all confused.
                                                                            … and so on.

Although there appears to be some uncertainty creeping into the witness evidence, the witness did not lie in either his/her statement to the police or in the evidence he/she gave in court. As far as the witness is concerned both versions are the truth.

So how can that be?

To find possible answers I suggest we get theatrical again and construct another scene. Okay, I know it’s not quite a night out on Broadway but bear with me anyway.

Here we go…
It’s late on a cold damp November evening – the 3rd of November to be exact. You’re hurrying to get home and take a short-cut down a dingy side street. Head down, you fail to notice two men arguing near the end of the street, until you’re close enough to hear them.

Punches are thrown and one man falls to the ground; the other stands practically motionless, obviously shocked by what has happened.

The man on the ground is clearly severely injured having struck his head on the sidewalk. The other man turns to you and says “you saw what happened, he threw the first punch and I was just defending myself”.

The police are called and soon establish you as the only witness. The fact that you are the only witness makes your statement of events very important as you are most likely to be called to give evidence in court.

So, will your evidence support or compromise the claims of self-defence or simply cloud the case in confusion?

To explore that question we look at the incident from two perspectives… we only have two because the injured man subsequently died. In the rest of the discussion the remaining man will be referred to as the defendant and you as the witness.

1) The defendant’s experience
           
1.1 Even before punches were thrown, it is likely the argument may have aroused certain emotions in the defendant, for example, fear and anger and evoked certain memories, for example, of how other such confrontations ended.

            1.2 Throwing and receiving punches can result in physiological and psychological arousal such as increased heart-rate and blood pressure; experience of physical pain; release of stress hormones; fear; anger; sight of blood; recall of memories of other confrontations, maybe of abuse and so on.

So it’s not hard to understand that the defendant had a lot of experiences occurring in a short interval of time. It is reasonable to assume that some of those experiences made a vivid impression on the defendant by virtue of their relevance and immediacy. It may be also reasonable to suggest that the details of the confrontation would be accurately recorded in the defendant’s brain.

But what of the overall picture of the confrontation – how well might the defendant’s brain have recorded that?

Well, let’s see…
We could argue that with a fight looming consideration of the background to the confrontation was not really a priority for the defendant. It seems unlikely that the defendant would be thinking thoughts such as “I wonder how this got started” or “I’m sure I didn’t say that” as a fist rapidly approaches his face. The defendant had more immediately relevant and threatening events to deal with – like protecting himself, the details of which needed his full attention. 

We should not be all that surprised then that if, after the event, the defendant seems certain about the details of the actual fight (“he struck me first”) and somewhat less interested or precise on what led up to the confrontation (“I’m not really sure how it started but I think it was because I said…”).

But what about the witness?
Is the witness going to be able to support the defendant’s self-defence claims? Well, the only way we can get a clue to that is by trying to reconstruct the witness’s experience.

Firstly, the witness observed two men arguing at the end of the street. It seems reasonable to expect that the witness’s first thoughts were about his/her own safety. So what the witness observed would most likely be processed through a filter of how the unfolding events might affect him/her. In that regard the witness may well experience feelings of fear and anxiety. However, such feelings would be aroused more in respect of self-protection in response to the situation rather than to the nature and origin of the confrontation.

What I’m trying to say is that the focus of the witness’s attention would be on self-preservation driven by anxiety – it would be immediately relevant and very personal and as such we would expect it to be imprinted in the witness’s brain. Under such circumstances it is unlikely that the witness would have been able to objectively view the confrontation and calmly observe who threw the first punch or recall precisely what the combatants were shouting at each other.

In short, it would seem reasonable to assume that the witness had nothing more than a general impression of the confrontation – the ‘big picture’, the background, if you will.

So what about the detail? What can we expect the witness to recall with clarity?

Once the witness had satisfied himself/herself about personal safety and arrived at the scene he/she will be exposed to visible and compelling evidence that a confrontation had occurred.  For example, an unconscious man on the ground with blood everywhere. Such stuff is immediate and relevant and cannot be ignored.

In addition, it is possible that the sights aroused emotions and evoked memories for the witness. There is good reason to expect that such detail would be accurately imprinted in the witness’s brain.

So let’s sum up where we are at…
We appear to have a defendant who is vague about how the confrontation started (overall picture), but is adamant that he didn’t throw the first punch and that he acted in self-defence (details).

We have a witness who, although he/she was able to observe the confrontation was initially concerned with their own safety and that in a sense filtered out many of the details of the unfolding confrontation. However, once the witness arrived at the scene he/she was able to observe the detail. None of that really helps the defendant’s case.

But we’re not finished with either party yet…
Things are actually a bit more complicated than I’ve painted so far. You may have heard about the concept of ‘right brain-left brain’ and while it has been wrongly used to imply that people are either right-brained or left-brained it does have application in a criminal case – the question is whether it will help the defendant. You may think I keep favouring the defendant. Okay, maybe I’m guilty on that count – but I know the whole truth… I’m writing it. Ha! Ha!

Anyway back to implications of the concept of ‘right/left brain’ dominance…
Some people are right-brain dominant, some left-brain dominant. Having said that when it comes to ability both hemispheres of the brain work together – it’s not as if one or other hemisphere switches off  

Okay, but what has that got to do with our witness and defendant?
Plenty, as it relates directly to the ability of both the witness and the defendant to accurately and consistently recall the details and the overall picture of the event.

Let me explain how….
People that are left-brain dominant more readily absorb details and logically arrange the bits in sequence to form the ‘big picture’. It’s basically a sequential, linear process – what I mean is that one step follows the previous one in sequence.

On the other hand, right-brain dominants are the ‘big picture’ people. They start with the whole – the end point, if you will – and break it down in a somewhat random process (in the sense that they may jump from one thing to another) to fill in the details.

Bear in mind that what is being discussed here are generalizations not rigid barriers. By that I mean it is entirely possible for right brain dominants to process logically and left-brain dominants to jump from one point to another in random fashion. Either type can learn to enhance their less dominant characteristic.

Anyway the important thing is that you see how the dominant characteristic could undermine the accuracy of either or both the defendant’s and witness’s records of the event?

Let’s take an example…What if our witness is a right-brain dominant. It would probably mean that his/her ability to recall details of the events leading up to the knockout punch is compromised..

How might this manifest in a statement to police or in evidence given in the courtroom? Time since the event is also an important factor. The more the time elapses the more difficult a right-brain dominant may find it to recall details.

The witness is tries to recreate the big picture each time he/she is asked what he/she saw. If he/she manages to get a very similar recall each time then that provides a sound framework for consistent responses about the details.

On the other hand, if the witness fails to recreate a similar ‘big picture’ each time he/she questioned then there is a likelihood that variations in the recall of details may occur that in turn may undermine the credibility of the evidence or at least provide openings for doubt to be exploited..

Perhaps this explains why in the TV police dramas different officers ask interviewees the same questions on a number of different occasions.    

Back to our defendant… if he happens to be a left-brain dominant he will be all the more confident about the details of the actual event and perhaps somewhat vaguer about what lead up to it and/or what might have been said that turned it into a fight.

Let’s draw it together and see whether or not we can help the defendant win the case…
It’s not looking too good for the defendant. Although he/she is adamant that they acted in self-defence our witness can’t absolutely confirm that the defendant didn’t throw the first punch. The witness didn’t help the defendant’s chances by presenting two slightly conflicting statements.

Of course, we know we can excuse the witness after all he/she was at first concerned with their personal safety rather than intimately observing the details of the actual confrontation as it unfolded. Add that the fact that he/she is right-brained and the degree of confusion was probably enhanced.  

Although the witness has provided two slightly differing accounts of what he/she saw both accounts are accurate as far as the witness is concerned. The variation may be due to the difficulty in recalling a consistent big picture of the confrontation which, as you might expect, in turn led to some confusion over the detail. On all occasions the witness was telling the truth!

Unfortunately for the defendant we have a situation in which the prosecution will aim to demolish the witness if he/she is put up by the defence. Since there are no other witnesses, I guess the defence is left with little alternative but to rely on character references and the power of its appeal to the jury.

Poor defendant… he too was telling the truth!

Have you had experience of a case in which the witness appeared to have told lies?

As always, your comments are most welcome. If you liked this post tell your friends about it – spreading the word helps keep this blog alive!

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