How is eyewitness testimony affected by the human mind? Answer: In every way!
Thank you for joining us again for this discussion on unreliable eyewitness testimony. Thus far we’ve discussed the court’s approach to eyewitness testimony, and what the majority of research is revealing about how inconsistent and untrustworthy eyewitness testimony can be. Moving forward, we will be looking at the science of memory today, and the effect it has on how we recall faces and events. For those of you just joining us, we recommend spending a few minutes getting caught up. However, for those of you who have been along for the ride from the beginning, let’s get to it…
According to Richard L. Huganir, Director of the Department of Neuroscience at Johns Hopkins, when we learn anything new at all, we form connections between the neurons in the brain, called synapses. They then create new circuits between nerve cells. Those synapses get stronger or weaker depending on how often we’re exposed to an event. In other words, the more you’re exposed to something, the stronger the connections get. Less exposure, however, means weaker connections. That explains why it can be so hard to remember things after only seeing or hearing them once. Recall that repetition always make it easier to remember things.
In most cases, eyewitnesses to a crime, or for witnesses who see the suspect at the scene, this is the first time they are ever seeing that person. This means their exposure to the person accused of committing the crime is very brief, and so the synaptic connection formed for that memory is very weak.
In addition, memories are subtly reconstructed in the brain every time they are recounted. People edit out details they believe to be extraneous, or focus on details that they believe to be relevant to their listener. This in turn affects the way they recall the event, so that the next time they tell the story, it is often slightly changed by the way they told it previously. When recounting events to law enforcement, this is of particular concern.
Witnesses who talk to police often remember events and people incorrectly in their retelling.
In a talk given by Barbara Tversky, Professor of Psychology and George Fisher, Professor of Law at Stanford, they discuss the issue of how memory can be effected without any outside influences. “Memory is affected by retelling, and we rarely tell a story in a neutral fashion. By tailoring our stories to our listeners, our bias distorts the very formation of memory—even without the introduction of misinformation by a third party.” The result they say, is that eyewitness testimony is innately suspect.
Taking into account the weak synaptic connection and the fact that the story is likely to change slightly every time it is recalled and retold, there is another factor that influences memories – emotion. It is a widely accepted consensus that strong emotions have an impact on memory formation. Stress and fear can cause acute and chronic changes in certain areas of the human brain, which can actually cause long-term damage. Additionally, over-secretion of stress hormones often impairs memory.
Although there are differences of opinion about how acute stress affects memory formation, both schools of thought point to difficulties in accurately recalling information. This is supported by studies that have conclusively shown that stress may enhance memory formation, but impairs memory retrieval. All of this proves that witnesses that are present during high stress events – shooting, robberies, rapes, kidnappings, etc – are not likely to recall events and people as accurately as they would be able to under less stressful circumstances.
Join us next time as we take a look at how suggestive questioning can affect the way memories are recalled, making police interviewing techniques very questionable during investigations. Until then, if you or a loved one have been accused of a crime in Michigan, contact us immediately at 866 766 5245. The skilled defense attorneys at The Kronzek Firm have decades of experience defending the people of Michigan against criminal charges and false accusations.