Impeachment and Rehabilitation Evidence in Wisconsin - Credibility of Witnesses

By John DiMotto

One of the most important decisions a jury must make is a determination of the credibility of the witnesses who testify at trial and the weight of evidence. In fact, in the preliminary jury instructions that are read to a jury prior to the introduction of evidence, the jury is instructed:

As a juror, your most important function is to weigh the credibility or believability of the witnesses. You cannot discuss intelligently any question on the verdict that will be submitted to you without first collectively discussing the testimony that you have heard which bears upon that question. It is mot important for you to consider, as you listen to the testimony of the various witnesses in this trial, whether they are believable.

Recognizing the critical nature of the credibility of witnesses determination, in every trial attorneys attack the credibility of the witnesses on the other side of the case. These attacks are usually directed towards four facets of credibility:

1) Accuracy of Perception.

2) Accuracy of Memory.

3) Accuracy of Narration.

4) The Witness's Sincerity.

Accuracy of Perception:

People perceive the world around them through five senses:

1) Seeing.

2) Hearing.

3) Speaking.

4) Smelling.

5) Feeling.

Depending on how the witness has perceived and obtained information will dictate how the accuracy of the perception is challenged. If a witness claims to have heard something, the circumstances in existence at the time the witnesses states he/she heard something will be critical. For example, if a witness claims to have heard people engaged in a conversation in which they were whispering, whether the witness had the ability to hear the whispering is critical. If the witness has hearing problems and ordinarily wears a hearing aid but on the day in question was not wearing it, this fact may well undermine the credibility of the witness.

Accuracy of Memory:

Not only must a person be able to perceive, but a person must be able to remember. If a person suffers from dementia, that fact may be critical in whether he/she has the ability to remember what the person claims to have perceived. If a person was using hallucinogenic drugs at the time of a perception, this fact may be critical in whether the person could truly remember what the person claims was perceived.

Accuracy of Narration:

While a person may have no impediments to perception and while a person may be able to remember what was perceived, if the person has difficulty communicating what he/she perceived and remembered, the trier of fact may not give it much weight. The ability to communicate is very important in terms of whether a witness will be believed.

Witness's Sincerity:

One of the most important aspects of credibility is the sincerity of the witness. What a witness says must have a "ring of truth" if it is to be given credit by the trier of fact. Sincerity makes a witness likable, and whether a person is or is not likable may be of the utmost importance to the trier of fact.

The four facets of credibility go to the "aura" and "gravitas" of the witness.

In my next post, I will look at Testimonial Capacity - how it can be impeached and how it can be rehabilitated.