False memories planted in your brain because of peer pressure are so strong that they could fool a lie detector, according to new Israeli research.
Scientists from the Weizmann Institute in Rehovot, working with their counterparts from University College London, have conducted experiments showing how easy it is to plant false memories - using social pressure.
Weizmann research scientist Micah Edelson said: "Humans are very social animals. It's important to know if what we remember is true. I am my memory. It's particularly important when it comes to remembering a crime, or deciding who to vote for."
The experiment, conducted in Israel and analysed in London, shows a unique pattern of brain activity occurs when false memories are formed.
Volunteers watched a documentary film in small groups and later took a memory test about the film. They then returned to retake the test, while having their brains scanned, but were given a list of answers that they were told had been written by their peers, some of which were false.
Almost 70 per cent of the time, participants conformed their answers to the rest of the group.
Taking the test a third, final time, having been told the answers were actually generated by a computer, some participants still seemed to rely on the false answers that they were given by their "peers".
The research showed that the two areas of the brain linked with memory and emotion, lit up on the scan when people changed their answers to fit in with their social group.
Mr Edelson said: "I would speculate that because the person really does believe his false memory, that he would pass a lie detector test. It's neurologically possible for a witness's memory of an event to truly change under social pressure."
"In the UK, Labour politician Peter Hain was accused of a bank robbery when some schoolboys saw him getting into his car just after the robbery, one thought it was him, and the rest agreed. It can also happen in politics. There's lots of social influence on you to make you remember how it was "under Blair" or "under Thatcher" - they aren't your own memories of actually what it was like for you. But they can influence how you vote."
Mr Edelson's experiment was conducted with Israeli neurobiologist Professor Yadin Dudai and UCL's Professor Raymond Dolan and Dr Tali Sharot, funded by a £62,000 Making Connections grant from Weizmann UK.
"This partnership was extremely fruitful and efficient," Mr Edelson said. "We have expertise in memory-related areas and UCL are world experts in
cognitive imaging. We hope to continue the partnership between London and Israel."
Weizmann UK's director Sheridan Gould said: "This is our way of countering ugly academic boycotts and actually encouraging Israeli and British scientists to work together, and
we are so pleased to see the impact it has had."