Written by Carl Davidson, Research First Ltd
If you’re in the business of influencing others (to buy something, to believe something, or to act differently), then it’s critical that you understand how the human brain really works. One of the important lessons emerging from the social sciences is that our intuitions about ourselves and others are often not as accurate or as insightful as we think.
While it feels like you’re reasoning your way through your life, that’s rarely the case. Instead, our brains are wired to take shortcuts, to be influenced by how things are framed, and profoundly shaped by what others are doing. When we talk about knowing something, we really mean experiencing what the neurologist Robert Burton called a “feeling of knowing”.
Part of the puzzle here is that we all rely on our memories to construct our ideas of what the future might look like. And while it feels like our memories are up to the task, they’re not really designed for it. The truth is, we don’t really recallmemories so much as reconstruct them from traces distributed throughout the brain. This makes memories what psychologists call ‘plastic’, meaning they can be shaped and reshaped as we replay them.
There is a long list of these memory biases to highlight just how unreliable our memories really but the problem with this line of argument is that it starts from an assumption that our memories should be accurate. That is, the emphasis on remembering obscures the role that forgetting plays for our brains. We tend to think about forgetting as a failure to remember but this misunderstands what our brains evolved to do. The reason you have a memory at all is to help you survive in an uncertain world. Memory exists to optimise decision-making, not to accurately capture and reproduce information.
As the psychologists Blake Richards and Paul Frankland have noted, this means forgetting is just as important to a healthy brain as remembering. This is supported by the fact we tend to forget memories about what happened to us (known as ‘episodic memories’) quicker than we forget memories about general knowledge (known as ‘semantic memories’). The reality is that those episodic memories might just not be very useful from a survival perspective. Which also means that not being able to remember how you know someone might be a feature of our brains and not a bug. It also explains why you’re unlikely to remember this blog, and why I won’t be too offended when you don’t.
 If you want to know more about the fallibility of memory, have a look at the work of UCLA’s Bjork Learning and Forgetting Lab (https://bjorklab.psych.ucla.edu/people/). A great place to start is with Elizabeth and Robert Bjork’s (1996) Memory, Academic Press, San Diego or Daniel Schacter’s (2001) The Seven Sins of Memory, Houghton Mifflin. The point about memory being a decision-making tool to help you survive in an uncertain world comes from Blake Richards and Paul Frankland’s 2017 paper “The Persistence and Transience of Memory” in Neuron, Volume 94, Issue 6, p1071–1084. The point about forgetting being a feature and not a bug is from Angela Chen’s (2017) “The purpose of memory might not be to record everything”, The Verge Jun 21, 2017.