Dr. Ayanna Thomas is called to court roughly once a month. The founder of the Cognitive Aging and Memory Laboratory at Tufts University, Thomas testifies for the defense — delineating the limits of eyewitness memory.
Like any witness, she takes an oath to “tell the truth, the whole truth, and nothing but the truth” each time she proceeds to the stand. But as she explained to the KSJ fellows on November 8 — her second visit to the program — “Telling the ‘whole truth’ and ‘nothing but the truth’ are at odds with each other. We are encouraged to be complete and accurate even though our memories don’t work that way.” She contends that eyewitnesses should simply be directed to tell “nothing but the truth,” recounting only the aspects of the crime they are certain they recall correctly.
Thomas first became interested in cognition during her undergraduate studies at Wesleyan University, eventually narrowing her focus to the fallibility of memory. Lately, she told the fellows, she has become especially interested in older witnesses — in particular, whether their memories and testimonies are affected by ageist stereotypes.
When older adults are asked to complete a memory task (like testifying in court), Thomas said, they tend to give more “conservative” accounts — erring on the side of caution because they fear saying anything that could confirm stereotypes of forgetful seniors.
In her experiments, Thomas compares memory in young and old eyewitnesses. She shows each participant a 20-minute clip depicting crime from a 1956 French film, then presents them with a “post-event narrative” — a written description of the crime, akin to an article we might see in a newspaper. Some of the information is incorrect or inconsistent with the original event. For instance, the film may show a ring being stolen, while the narrative suggests it was a necklace.
In one study, Thomas told her subjects that recalling any detail of the crime — gleaned from the film or the narrative — was acceptable; either would be considered correct. Nor was there any penalty for leaving an answer blank. That meant there would be no stigma attached to being forgetful. As she suspected, when older adults were freed from the threat of negative stereotypes, they performed much like the young adults.
But when they were worried about stereotyping, the older witnesses omitted bits of information. “Older adults under a high level of stereotype threat adopted a more conservative response strategy, which I actually see as a positive for an eyewitness,” Thomas said, adding, “These data blew my mind.”
To check her theory, Thomas devised an experiment in which older adults could no longer exclude facts they couldn’t precisely recall. This time, participants were instructed to ignore the narrative and just focus on the facts presented in the film. They had to answer all of Thomas’s questions, attributing the information to a specific source (the video, the narrative, both, or neither), even if it meant guessing.
“I also love these data, because the young adults look just like older adults under high threat in terms of incorrect attributions,” Thomas said. This indicates that older adults under high threat are likely to adopt a more conservative response strategy. In this context, stereotype threat encouraged older adults to testify more accurately, albeit less completely.
“Courts should really tell witnesses, both young and old, that accuracy is more important than completeness,” Thomas concluded.
KSJ fellow Robert McClure said he was intrigued by this idea. “This dissonance between telling the whole truth and nothing but the truth was really interesting, and should probably be changed throughout our court system,” he said.
In the future, Thomas said, she intends to shift her focus to the victims of crime, hoping to determine when is the best time after a traumatic experience for investigators to begin their questioning. In the meantime, she will continue traveling, attending musical performances, and watching horror movies with her husband and their two French bulldogs, Odin and Xena.