By Fiona Macrae
It has been the stuff of science fiction for decades. Now scientists have found a way to wipe out painful memories.
They have shown that if we are forced to recall something negative very shortly after the experience, it can be ‘rewritten’ for the better.
The finding could one day be used to help soldiers traumatised by the horrors of battle.
Researchers gave a group of volunteers mild electric shocks while they looked at a picture of a coloured square.
The next day they were subjected to the same combination, to bring back the painful memory, before repeatedly being shown the picture alone.
They were again shown the image alone the day after that – and when their levels of anxiety were measured their fear had all but gone, the journal Nature reports.
Being shown the picture without the shock within ten minutes after their second exposure to the picture with the shock seemed to rewire the brain’s response.
Dr Daniela Schiller, from New York University, said: ‘This suggests that during the lifetime of a memory there are windows of opportunity where it becomes susceptible to becoming permanently changed.’
With animal experiments giving similar results, it seems that our memories are not set in stone. Instead, they can updated with new information during a brief period between being retrieved and re-stored.
The exact amount of time is not certain but is clearly under six hours.
Professor Phelps said: ‘Timing may have a more important role in the control of fear than previously appreciated.
‘Our memory reflects our last retrieval of it rather than an exact account of the original event.’
Researcher Dr Daniela Schiller said: ‘Our research suggests that during the lifetime of a memory there are windows of opportunity where it becomes susceptible to become permanently changed.
‘By understanding the dynamics of memory we might, in the long run, open new avenues of treatments for disorders that involve abnormal emotional memories.’
Earlier this year, Dutch researchers showed that beta-blocker drugs used to treat heart disease can impact on memory.
Other researchers have had success with anaesthetic gases.
However, the field is not without its critics, with some claiming that holding onto and reviewing bad memories helps us learn from our mistakes.
The ability to remove memories has been the stuff of science fiction for decades.
In the film the Eternal Sunshine of the Spotless Mind, a couple played by Kate Winslet and Jim Carrey, used a technique to erase memories of each other when their relationship turned sour.