Given a jiggle, the synapses start firing... could it be that we can remember everything?

Connections: the human brain has about 86 billion neurons

Many years ago – more than I can actually remember – the late Bob Ellis and I conducted a memory experiment. With fellow writer Annie Gillison we decided to choose a year, pretty much at random, and see what we could recall about it. No Googling back then, no Wikipedia. Just the mind’s eye.

We began by going solo. Writing personal lists without discussion. Long ones. But then things slowed down and pretty much petered out. Not only the political and the cultural but the personal. Then we opened things up and the strangest thing happened, or began to. By bouncing off each other, the memories began to trickle – and flood. Not that our lives had much intersected – I hardly knew Annie while Bob and I, at that stage, weren’t close. Yet we experienced an unstoppable, exhilarating process. Together we were more than the sum of our parts.

Before his death Bob and I talked about the experiment – and the conviction we had at the time that given the right stimulus, almost everything that ever happens to us can be recalled. At some point Bob had read of fine needles being pushed into a brain and apparently triggering the same phenomenon as our séance. Given a jiggle, the synapses start firing out of the depths of the subconscious. Could it be that we can remember everything? That it’s all stored in the attic or basement?

This ancient scribe has never been persuaded by “repressed memory”. I’ve got countless memories I’d like to repress but no luck. Could it be that rather than repressing or “pressing the delete”, these damned brains of ours are hoarders? Between our ears we house 86 billion neurons, and that’s before you factor in those pesky synapses. (If you don’t believe me ask Google, our collective memory.)

That many neurons is often compared with the number of stars in our Galaxy – but that’s an overstatement. The Milky Way has about three times more stars than the brain has neurons. Intelligent life in outer space? Remember Eric Idle’s whimsical request for evidence of intelligent life on Earth. Evidence for stupidity abounds – notably among our politicians and the people who vote for them. But our individual noggins are, quite clearly, super-computational. On one hand we can’t remember where we left the car keys. On the other we came up with the Theory of Relativity.

Not all neurons are born equal. In trying to measure IQ it’s been found the common fruit fly has 2500 that count (in the forebrain). The bee? 170,000. The common house mouse has 14,000,000. The budgie has 14,600,000. The Asian elephant, with its legendary memory, 6,775,000,000. Onward, ever upward. But enough. Like those blokes in Monty Python, thinking makes my brain hurt.

Back to my original issue. Do we remember everything? Or rather, can we if we ask the brain the right questions? I haven’t the foggiest – and the experts seem to disagree. Perhaps even our billions of neurons need their rest and relaxation and chuck lots of memories out. Like the stuff we leave on the footpath for council collection. It’s also fascinating that we remember stuff that didn’t actually happen – like dreams. Tunes and lyrics. People collect these enormous song lists and keep them on their smartphones and other devices that have, yes, huge memories. But I remember vast numbers of songs I didn’t like in the first place.

Now, where the hell are my car keys?