A new study from the University of Birmingham and the MRC Cognition and Brain Sciences Unit in Cambridge has shown how intentional recall is beyond a simple reawakening of a memory; and actually leads us to forget other competing experiences that interfere with retrieval. Quite simply, the very act of remembering may be one of the major reasons why we forget.

The research, published in Nature Neuroscience, is the first to isolate the adaptive forgetting mechanism in the human brain. The brain imaging study shows that the mechanism itself is implemented by the suppression of the unique cortical patterns that underlie competing memories. Via this mechanism, remembering dynamically alters which aspects of our past remain accessible.

Darker side of memory

Dr Maria Wimber, from the University, explained, 'Though there has been an emerging belief within the academic field that the brain has this inhibitory mechanism, I think a lot of people are surprised to hear that recalling memories has this darker side of making us forget others by actually suppressing them.'

Selective memory and self-deception

Dr Michael Anderson, from the MRC Cognition and Brain Sciences Unit at Cambridge, who co-led the study, said 'The idea that the very act of remembering can cause forgetting is surprising, and could tell us more about selective memory and even self deception.'

Dr Wimber added: 'Forgetting is often viewed as a negative thing, but of course, it can be incredibly useful when trying to overcome a negative memory from our past. So there are opportunities for this to be applied in areas to really help people.'

This work was funded by the Medical Research Council (MRC).