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Why alcohol isn't the only excuse for unreliable memory

Alcohol may lead to forgotten moments, but even sober recall can be fickle.

A critical time in my butterfly-like transformation from idealistic student to institutionalised academic cynic was my honours year. Honours is a peculiarly colonial add-on year of specialised study that follows your bachelor’s degree. It’s a critical year for many students and can define where they end up. During my honours year, I met Seema Assefi, an exchange student from the US.

Assefi returned to New Zealand a couple of years later to complete a PhD at Victoria University, researching aspects of memory. I don’t know where she is now, but if she’s back in the US I wonder if she’s following the impeachment process (or “circus”, if you’re a Republican). I’m intrigued, as ever, by how fundamentally psychological it is: Who knew what and when? How do we judge intent? How did the actors infer the President’s intent?

How do we take it when people say, “I don’t recall”, in response to a question about something as evocative as, say, a phone conversation with the US President? During his 1990 Iran-Contra testimony, then-President Ronald Reagan said, “I don’t recall …”, and, “I can’t remember …”, more than 80 times.

There are lots of reasons we don’t remember. In Reagan’s case, there’s an interesting question of whether his memory was impaired – he was officially diagnosed with Alzheimer’s in 1994 but there had been questions about his neurological health even before 1990.

I’m not suggesting for a second that this next explanation might be implicated in Trumpgate, but you’ve probably seen the “Department of Lost Nights” public-education campaign on TV, in which a curly-headed fellow has too many beersies and watches his memories of the evening disappear. Yup, booze can do it to ya. If you drink too much for long enough, there are long-term issues with memory, such as difficulty learning new information or with long-term recall, that are symptoms of Korsakoff’s Syndrome.

But most people with any experience will have the sense that even a few drinks can start to disrupt the ability to form long-term memories. You’re probably less aware that this has something to do with the hippocampus, the brain structure involved in autobiographical memory. In the 1960s, it was observed that the symptoms of extreme alcohol consumption look a lot like the symptoms that follow damage to the hippocampus. As an aside, being exposed to alcohol in the womb predicts a greater propensity for alcohol-related memory blackouts.

Which makes Seema Assefi’s PhD research so very interesting. Let’s imagine that you’ve been out for a few drinks and, on the way home along Lambton Quay, you witness a man stealing things in a bookstore. Sometime later, the police might want to ask if you remember particular things happening, such as whether the man shoplifted a stapler, for instance.

This is more or less what Assefi and her supervisor, Maryanne Garry, did in a laboratory experiment involving a video of said shoplifting. Unsurprisingly, laboratory participants plied with vodka and tonic (drunk over 13 minutes) were more vulnerable to memory errors than those given tonic only. The “alcohol” group were also more confident in their answers than non-vodka controls.

Except (drum roll), although participants watched the alcohol being dispensed from a real bottle, nobody had actually been given any vodka. Poorer memory performance was, in short, the product of a nocebo effect – we know that booze can affect our memory and, if we think we’ve had some, we behave as if we have.

It’s not just alcohol nocebos that do this, either. Giving a person a sugar pill and telling them it’s a chemical that affects memory actually does affect memory.

So, memory is apparently a bit like a sock drawer. You don’t necessarily know if you’re going to pull out a pair.

In the case of the impeachment inquiry, though, I imagine that Democrats are really, really hoping it’s a match.

This article was first published in the December 7, 2019 issue of the New Zealand Listener.