Recently I looked at a project that is attempting to make machines better not at learning new things, but forgetting what it has already learned.  The idea is that by doing this it will greatly improve both security and privacy of systems that require huge data sets to operate effectively.

A recent study by a Spanish team suggests that the brain undergoes a similar process.  The research suggests that as we’re learning a new skill, our brain is actively trying to forget at the same time.

“This is the first time that a pathway in the brain has been linked to forgetting, to actively erasing memories,” the authors say.

Missing links

In its basic form, the brain helps us to learn by creating associations that we can then try and remember.  Much of this work is done in the hippocampus, with information entering it via one of three different routes.  The more we learn, the stronger connections between neurons become.

In experiments, the researchers blocked off this route and the mice in the experiment became incapable of learning a simple response to a stimuli.

Interestingly, if they had already learned the correct response prior to the pathway being blocked off, they could retrieve it from their memory, meaning that the retrieval is done via one of the other two pathways.

This didn’t mean blocking the main pathway had no consequences however.  Instead, as the connections were weakened, the memory gradually began to fade.

“Simply blocking this pathway shouldn’t have an effect on its strength,” the team say. “When we investigated further, we discovered that activity in one of the other pathways was driving this weakening.”

Circumstantial amnesia

Interestingly, this only happens in certain circumstances.  For instance, when the main route into the hippocampus was blocked, the other connections retained their vitality, with the authors suggesting this is because of the finite capacity of the brain resulting in a trade-off in strength between connections.

“One explanation for this is that there is limited space in the brain, so when you’re learning, you have to weaken some connections to make room for others,” they say. “To learn new things, you have to forget things you’ve learned before.”

Now, suffice to say, this experiment was conducted on mice, and genetically engineered ones at that, but the team believe that they could potentially develop a drug that activates this process in a non-modified brain.  They believe it may be useful in helping to overcome traumatic events for instance.

Eternal Sunshine of the Spotless Mind may not be that far away after all.