The Eye Knows Better Than the Brain What It Has Seen

As the US Supreme Court is hearing arguments that eyewitness testimony is not a reliable category of evidence, researchers are proving that eye witness testimony might actually be the answer.

Police and lawyers have long struggled with the reliability of eyewitness testimony. In 12 Angry Men, the eyewitness testimony that may have served to convict a young man of murder is famously dismissed because of the eyewitness’ myopia, but even without refractive error, eyewitness testimony is unreliable. According to recently released research, about 75% of DNA exonerations come in cases where an eyewitness misidentified the perpetrator.

This is due, in part, to the pliability of memory, which can be altered by an act as simple as retelling what happened. By the time a witness is asked to identify a perpetrator from a line-up, he or she may have been asked to retell the events several times, and each time the memory is accessed, it is also resculpted, and the actual visual memory is lost and replaced more or less with a set of descriptors.

However, it turns out the eyes themselves also have a memory, distinct from the one in the brain, that might be a better way to make eyewitness identifications. According to research to be published in Psychological Science, eye movements more accurately identified a remembered face than conscious identification.

The researchers gave students a set of 36 faces to study. These faces were also subtly morphed to create slightly different faces that were not seen by the students. Then students were shown 36 3-face displays and identify a face they had seen, if there was one. If there was not a face they had seen before in the display, they were to pick any face and verbally say whether the face they were looking for was there or not. Eye tracking was used to look at the movement of their eyes as they were making their identifications.

The research showed that eye movements disproportionally moved to the previously seen face even before an identification was made. However, this memory is not immune to rewriting. Once the person had identified a face as having been seen before, the eyes kept moving to the “known” face as if it had been seen before, whether it had or not. In the words of researchers, “pre-response viewing seems to reflect actual experience, and post-response viewing seems to reflect the decision making process,” which leads the eye to “endorse” the face the brain has decided is the right one.

This research is in its early stages, but perhaps it will in the future allow for more reliable eyewitness reports and fewer wrongful convictions.

Also helpful in being a reliable eyewitness is having your refractive error corrected. To learn more about LASIK, please talk to a local ophthalmologist today.