How Malleable Are Memories?

This post is a review of Memory Lane: The Perfect Imperfect Ways We Remember. By Ciara Greene & Gillian Murphy. Princeton University Press. 232 pp. $29.95.

Many people believe that their memories preserve events exactly as they occurred and store them in their brains. But, as Elizabeth Loftus, an influential psychologist, has demonstrated, “Memory works a little bit more like a Wikipedia page: You can go in there and change it, but so can other people.”

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In Memory Lane, Ciara Greene, a professor of psychology at University College Dublin, and Gillian Murphy, a professor of psychology at University College Cork, draw on recent scientific research to provide an informative and accessible primer on how memory affects behavior.

Memory Lane begins with a brief taxonomy of memory processes – short-term memory: working memory; procedural memory (skills that have become automatic, like tying shoelaces and typing); declarative memory (including childhood experiences we can recall and describe); episodic memory (the menu at last night’s dinner); and semantic memory (Paris is the capital of France). Synaptic plasticity enables us to form new memories and update old ones. Each time we recall a memory, it may be slightly different, depending on our emotions then and now and on accurate or erroneous details introduced by other people.

The authors acknowledge that memories are malleable and can have harmful consequences. Along with many other psychologists, however, they are skeptical of the concept of “repressed” memories used in a raft of child sexual abuse prosecutions in the 1980s and 90s. In the McMartin Pre-School case, the longest and most expensive criminal trial in U.S. history, which resulted in no convictions, Greene and Murphy show how investigators, who would not take no for an answer, used leading questions to plant memories in hundreds of children, who asserted that teachers and staff got them to play naked movie star games, dig up coffins, participate in satanic rituals and drink blood in tunnels under school buildings.

Citing a number of experiments, including a unicycling clown unnoticed by pedestrians walking across a college campus, the authors also indicate that “inattention bias” raises questions about eyewitness testimony. As does the fact that most people are better at distinguishing among individuals in their own race than in other races.

Nonetheless, Greene and Murphy maintain that most of the time, retrieval and reconstruction of memory serve us well. Far more than its flaws, they add, our expectations about the reliability of memory “cause us the most trouble.”

Forgetting mundane details of life, the authors remind us, often gets a bad rap. Forgetting actually helps clear the deck for retrieval of more important information. A tendency to remember or misremember more positive events – grades that are higher than they actually were – can enhance satisfaction and self-esteem and reduce anxiety.

Greene and Murphy also present a glass half-full analysis of (relatively benign) false memories. Citing studies that found a link between projecting ourselves into imagined pasts and creative thinking, they assert that a memory system that only recalled actual experiences could hinder us from responding flexibly to unforeseen events.

The authors indicate that false memories about fake news – “I heard that before” – tend to occur when the “information” aligns with our beliefs and is repeated often. They report that when police officers are shown body camera footage, some of them misremember the perspective they had in the moment. Greene and Murphy also cite studies indicating that false memories can help people alter their diet and eat more healthily.

Greene and Murphy conclude with a plea to readers of their book to understand that evolution did not design human memories “to be perfect recording devices.” And to recognize that memory is fallible and an inaccurate or incomplete memory, in and outside of a court of law, “is not a reliable indicator of deception.”

Fair enough. Less convincing, however, is their claim that the ways we humans remember is “perfectly imperfect.”