Thursday, October 18, 2018

How Memory Offers Clues & Red Herrings

In the recent Brett Kavanaugh hearings, Christine Blasey Ford's testimony accusing Kavanaugh of a teenage sexual assault ignited a public discussion of the reliability of witness and victim memory of traumatic events. Many people seem to think that memory is like a videotape and that gaps undermine credibility, and also that time can erode memory to the point that mistaken identity is likely. Unfortunately, the public discussion is pumping out more misinformation than scientific and experiential fact. While some Kavanaugh backers suggested Ford's story was probably a case of mistaken identity, mistaken identity is unlikely in cases where the perpetrator is known to the victim or witness as in Ford's case. Mistaken identification most frequently occurs when the perpetrator is a stranger, when the accused is of a different race than the victim or witness, and when a weapon is used so that the victim/witness naturally focuses on the threat (knife or gun, for example) rather than the threatening person. Other commentators suggested that the gaps in Ford's memory undermined her credibility for them. Yet scientific research shows that what the brain encodes and is able to retrieve about a trauma is naturally spotty. Specifics such as exact location, date and time (unless tied to a memorable marker such as a holiday or work routine or well-known place) are commonly blurry, while other details are burned into the mind by intense negative emotion and stress. It is also true that memory can be manipulated, that people may fill in missing details from other memories or even be influenced by police and witness cues to create a complete scenario. As a result, testimony with gaps in memory can actually be more reliable, while a detailed story confidently asserted can be taken with a grain of salt. Plus, excess alcohol consumption (as alleged for Kavanaugh and his friend) can black out memory of events even if the person never passes out. For a mystery writer, characters' memories of traumatic events are important for creating both vital clues and red herrings. The starting point of many plots, especially cold case detective stories, involves witnesses and victims with gaps in their memories and conflicting accounts. Plots also make use of confident testimony that turns out to be misleading. Because mystery authors need to make plot twists realistic and believable, they need to avoid the kind of misguided assumptions about memory and trauma currently bandied about by politicians and TV talk chatter. For an easy-to-understand expert take, see https://blogs.scientificamerican.com/observations/how-reliable-are-the-memories-of-sexual-assault-victims/