Gideon asked:

Would you like to be given the ability to remember clearly everything that has happened to you or that you have experienced in your life?

Why? or why not?

Answer by Craig Skinner

A healthy memory, broadly speaking, remembers what is significant and forgets the rest. I have already forgotten the make and colour of the car next to mine in the supermarket car park today although no doubt I noticed it at the time.

There are many examples of normal people who train their memories, using mnemonics, to remember vast amounts of unrelated information, often for entertainment purposes. And of ‘idiot savants’ who can instantly tell you the day of the week for any past date. And of taxi drivers who develop an enlarged hippocampus (the part of the brain storing memories) through learning the exact layout of all the streets in London.

But genuine cases of detailed day-by-day recall going back many years (‘Hyperthymesia’ from Greek thymesis = memory) are very rare. The first case described in a medical journal was in 2006. The subject said she had a ‘movie in my mind that never stops’, and she had difficulty organizing and categorizing information. Typically, it is an exhausting business, disrupting the person’s ability to live in the present and plan for the future.

Many years before any medical description, a perceptive fictional account was written by Jorge Luis Borges in his short story ‘Funes the Memorious’ about a peasant who, after a fall from a horse and ensuing paralysis, developed total recall of his past life. He remembers the exact position and location of every leaf he ever saw, and when he saw it, and the detailed pattern of its veins; the exact size, shape and arrangement of the clouds for every time he looked at the sky, and so on. Sometimes he recalls a whole day in moment-by-moment detail, and of course it takes him a whole day to do this. He had no need of a number system: he gave every individual number, thousands of them, a separate name. But was incapable of ‘ideas of a general, Platonic sort’ – he couldn’t grasp that the symbol ‘dog’ embraced so many unlike individuals, or even that the dog seen from the side at 3:14 had the same name as the dog seen from the front at 3:15. He had no categories, only perceptions (or memories of them).

So, as we struggle to form organized memories to draw upon for, say, answering exam questions, let us be grateful that our brains don’t get clogged up with every detail we perceive.