Most memory research has concerned itself with learning over time, but many memories, of course, become fixed in our mind after only one experience. The mechanism by which we acquire knowledge from single events is not well understood, but a new study sheds some light on it.
The study involved participants being presented with images degraded almost beyond recognition. After a few moments, the original image was revealed, generating an “aha!” type moment. Insight is an experience that is frequently remembered well after a single occurrence. Participants repeated the exercise with dozens of different images.
Memory for these images was tested a week later, when participants were again shown the degraded images, and asked to recall details of the actual image.
Around half the images were remembered. But what’s intriguing is that the initial learning experience took place in a brain scanner, and to the researchers’ surprise, one of the highly active areas during the moment of insight was the amygdala. Moreover, high activity in the amygdala predicted that those images would be remembered a week later.
It seems the more we learn about the amygdala, the further its involvement extends. In this case, it’s suggested that the amygdala signals to other parts of the brain that an event is significant. In other words, it gives a value judgment, decreeing whether an event is worthy of being remembered. Presumably the greater the value, the more effort the brain puts into consolidating the information.
It is not thought, from the images used, that those associated with high activity in the amygdala were more ‘emotional’ than the other images.
 . Uncovering Camouflage: Amygdala Activation Predicts Long-Term Memory of Induced Perceptual Insight. Neuron [Internet]. 2011 ;69(5):1002 - 1014. Available from: http://linkinghub.elsevier.com/retrieve/pii/S0896627311001115