The Witness Problem : Human Memory is Fallible and Vulnerable : Which Sense Organ Gives the Most Reliable Testimony? The Eye or the Ear?

Human memory is fallible and vulnerable, which has special consequences for the law.

The Stanford Journal of Legal Studies has a review by Laura Engelhardt of The Problem with Eyewitness Testimony, a talk by Barbara Tversky, Professor of Psychology and George Fisher, Professor of Law, writing:

In a presentation sponsored by the Stanford Journal of Legal Studies, George Fisher placed Barbara Tversky’s research on memory fallibility into the context of police investigations and jury verdicts, discussing the relevance of such research to our system of justice….

and concluding:

The courts’ reliance on witnesses is built into the common-law judicial system, a reliance that is placed in check by the opposing counsel’s right to cross-examination—an important component of the adversarial legal process—and the law’s trust of the jury’s common sense. The fixation on witnesses reflects the weight given to personal testimony. As shown by recent studies, this weight must be balanced by an awareness that 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.

The familiar problems summarized in the Engelhardt review are exacerbated by new studies relating to the fallibility and vulnerability of the brain when forced to choose between conflicting senses.

If our brain is faced with a conflict of senses in which sight gives us one answer and hearing gives us another answer, which sense prevails – audio or visual?

Natalie Angier at the New York Times Science Basics in her article, When an Ear Witness Decides the Case, informs us of a new aspect to human fallibility – sensory conflict:

Spoken clearly, the sounds “dah” and “bah” are easy to distinguish. Yet if you play a film clip in which the soundtrack says “dah” while the image on the screen shows a mouth saying “bah,” people will swear they heard “bah.”

If you ask people to count the number of times that a light flashes, and you flash the light seven times together with a sequence of eight beeping tones, people will say the light flashed eight times.

When confronted with conflicting pieces of information, the brain decides which sense to trust. In the first scenario, those clearly percussing lips could never be articulating a “d,” and so vision claimed the upper hand. But on matters that demand a temporal analysis, and making sense of similar sounds in a sequence, the brain reflexively counts on hearing.

Such and similar evidentiary problems in the law can lead to wrongful convictions.