How rats, humans are able to actively forget distracting memories

CAMBRIDGE: Our ability to selectively forget distracting memories is shared with other mammals, suggests new research from the University of Cambridge.

The discovery that rats and humans share a common active forgetting ability – and in similar brain regions – suggests that the capacity to forget plays a vital role in adapting mammalian species to their environments, and that its evolution may date back at least to the time of our common ancestor.

Quite simply, the very act of remembering is a major reason why we forget, shaping our memory according to how it is used.

The human brain is estimated to include some 86 billion neurons (or nerve cells) and as many as 150 trillion synaptic connections, making it a powerful machine for processing and storing memories.

We need to retrieve these memories to help us carry out our daily tasks, whether remembering where we left the car in the supermarket car park or recalling the name of someone we meet in the street.

But the sheer scale of the experiences people could store in memory over our lives creates the risk of being overwhelmed with information. When we come out of the supermarket and think about where we left the car, for example, we only need to recall where we parked the car today, rather than being distracted by recalling every single time we came to do our shopping.

Previous work by Professor Michael Anderson at the Medical Research Council Cognition and Brain Sciences Unit showed that humans could actively forget distracting memories, and that retrieval plays a crucial role in this process. His group has shown how intentional recall of a past memory is more than simply reawakening it; it actually leads us to forget other competing experiences that interfere with retrieval of the memory we seek.

“Quite simply, the very act of remembering is a major reason why we forget, shaping our memory according to how it is used,” says Professor Anderson. — Cambridge News