One of the most quietly unsettling findings in psychology, for my money, is “verbal overshadowing” – a weird fact about memory that’s liable to make you wonder if anything you believe about your life is really true. The finding is this: putting your experiences into words – talking about them with others or writing them down – makes you less likely to recall them accurately. If you were to witness a mugging, say, then scribble a record of what you’d seen, you’d be more prone to misremember than if you’d written nothing. Or think of all those times you’ve told friends about that ridiculous thing your boss said, or how you felt when you heard the presidential election result, or what it was like when you went into labour: in all likelihood, none of those conversations fixed the experience more vividly in memory. They probably distorted them, so your recollections may bear little resemblance to the truth. This has consequences far graver than the accuracy of your anecdotes: Elizabeth Loftus, a leading researcher of verbal overshadowing, advocates for those wrongly convicted as a result. It’s a horrible irony: in trials we need eyewitnesses to give statements. Yet the act of giving a statement undermines your value as an eyewitness.
On closer inspection, this psychological oddity starts to look less strange. Language, as the linguist Nick Enfield points out, pretty much exists in order to categorise things – to sift the chaos of reality into the pigeonholes provided by our pre-agreed words. (He chose verbal overshadowing as his answer to the Edge website’s annual question this year: “What scientific term or concept ought to be more widely known?”) And putting something in a pigeonhole means not putting it into others, by definition. To describe someone as having three dogs is to focus on what the animals share – they’re dogs – and to disregard the fact that they’re a great dane, a sheepdog, and a yorkshire terrier; or old or young, excitable or placid. The research on verbal overshadowing, Enfield writes, suggests this pigeonholing overwrites the previous memory: “When words render experience, specific information is not just left out, it is deleted.” Even the best writer must unavoidably misrepresent the world – we couldn’t communicate otherwise – and the work of Loftus and others seems to show this misrepresentation can be permanent.
Yet this annoying feature of our brains is surely the flipside of an extremely useful one: the way that verbalising your problems – by keeping a journal, or just talking to yourself – renders them more manageable, whether or not you come up with solutions, or share what you’ve written. To put worries into words is to categorise them, and thus get them under control: the very fact you can express them means they haven’t entirely got the better of you. I’ve never managed to keep a diary, in the sense of a record of events, and verbal overshadowing implies it would warp my memories anyway. A journal, on the other hand, harnesses that effect: it works because it transforms the material. Words change things, and thereby us.