The right way to think about memory

Computational Neuroscience is a great class. If you are at all interested in how the mind works, definitely check it out, especially the introduction. One thing it's forever changed is how I view memory.

Culturally, we think of memory as a lockbox where we store things, similar to a computer hard-drive. When learning, I'm storing things into this box and at a later date, I will open the box and pull these things out. We have long accepted the fact that the lockbox is lossy, but the lossiness is confusing as it's unpredictable yet not random. I know your first reaction is to blame the gypsies, but please allow me to first propose an alternative explanation.

The lockbox metaphor is very flawed and leads to poor conclusions when approaching the subject of memory. The physical basis of memory, as far as we know, is Hebbian plasticity, where the synapses between neurons that fire repeatedly are strengthened. The classic example is a three neuron system where the first neuron fires when a growl is heard, the second neuron fires when a tiger appears, and the third neuron fires to get you to run like a motherfucker. The first time you hear a growl you'll think nothing of it because you don't associate it with the tiger. However, the tiger then appears, you run, and the synapse between the first and third neurons is strengthened. It is actually strengthened substantially because of the emotional nature of running for your life.

Extend this to the scale of trillions of synapses and the scope of many years. You can quickly see how memory is not about storing things, but linking things together and keeping them linked through experiences.

The way I think of memory now is as a beach. You can write words and draw pictures in the sand, but waves will slowly wash these away bit by bit. You have to repeatedly write and draw the things you care about and with effort, you can carve the words in more so that they are harder to wash away. Life is all about figuring out what you want your beach to look like.

Hence, life's a beach.