How do we remember this (and not that, or the other thing)?

The Neurocritic has a fascinating report on recent research exploring memory interference. One of the primary problems with memory is deciding what to remember and what to forget. As an example of the scale of the problem, if we recorded every image we ever saw in its raw format, we'd soon exhaust our memory reserves. And what if we remembered every word we'd ever read, instead of recalling the larger sense of what we learn? Again, eventually we'd run out of space.

When we encounter new images or words, we must decide which memories should be discarded, and which we should keep. Memory interference is one mechanism we use, and one type of memory interference is one that privileges older memories over new ones. It can make sense: if we've retained an item in memory, there's probably a good reason. It's more likely that the new information is just noise.

The new research has identified the region of the brain that's responsible for this type of interference:

The research set-up was designed to be a simplified version of many everyday memory challenges, says Postle. Without a good sorting mechanism, our brains would be utterly confused by the vast amount of observations, ideas and memories that we have stored away. We might, for example, dial the phone number of the friend we just called rather than the one we intended to call.

In previous studies of interference, the IFG consistently lit up in brain scans, showing that it does something when the memory tries to deal with interference. But the IFG could simply be contributing some type of generic processing power to the task, says Postle.

However, the new study proved that the IFG is essential to blocking interference, he says, because accuracy plummeted when the IFG got a brief jolt of magnetic stimulation at the exact moment when the subject was confronting confusion.

Read the whole article for a more extensive synopsis of the research, with really cool diagrams.

In other news:

• When good brains turn violent
• Language adaptations in old age: How the brain maintains language ability as it deteriorates
• Liberal guilt makes white people act like jerks
• Brits like their ethics books (you can also find out who I used to play poker with)
• Another misleading headline? "Promoting Self-weighing In Teens Is Not Helpful To Weight Management, Study Shows." This seems to me to be an example of mistaking correlation for causation.