The brain is not rubber: to remember something, you must forget something else

It seems that the old Buddhist parable that you can’t pour new knowledge into a full vessel of the mind is confirmed by researchers studying the work of the human brain. Scientists from the University of Birmingham and the Institute of Behavioral and Clinical Neurology in their new work prove that in order to include new memories in the brain, it is necessary to weaken and even remove old ones.

Researchers examined brain function using a functional magnetic resonance imaging apparatus. The subjects were first shown 144 pairs of words and images. Then they tried to remember 72 pairs, that is, half of the pairs from the first set, by building associations between the word and the image. After that, they began to memorize the second half of the set. And in the last phase of the experiment, they tried to recall the associations from the first set.

The fMRI scanning device produced information in the form of a three-dimensional image composed of voxels (three-dimensional pixels), each of which showed the level of blood circulation in this part of the brain. The brain was scanned four times - after remembering the first set, after remembering the second, then when trying to remember the first set and last time - when trying to distinguish the pictures that they remembered from those that they had not seen before.

As a result, scientists claim that they were able to see the mechanism of adaptive forgetting in action. Attempts to recall associations from the second set led to forgetting the first. When subjects were asked to recall the second set, the first they could no longer remember with the same efficiency. When they were shown pictures from the first set, the levels of brain activation when trying to remember the necessary words were even lower than when viewing pictures that were not included in the set.

From this, it was concluded that previous memories are actively suppressed by the brain. It turns out that forgetting is as important a brain function as remembering.