A new study shows that people's painful or frightening memories can be erased. A group of cognitive scientists have revealed that people can forget pain if they are exposed to specific stimuli during "memory reconsolidation," the hour or so after you recall a memory.
The researchers first proved this using rats. According to ABC News:
[Neuroscientist Marie Monfils'] team first taught rats to associate a musical tone with a slight electric shock. Playing the tone with no shock generally causes rats to freeze in fear. When her team played the tone over and over again, 19 times, the rats displayed less and less fear. This is standard extinction therapy. However, a month later their fear of the tone returned, strong as ever.
To make the effect permanent, Monfils team jogged other rats' memories of shocks just once, waited an hour for memory reconsolidation to begin, and then played the tone over and over.
"It's very simple and almost naïve to think it would work," Monfils says. But the fearful memories disappeared permanently.
Later, another research group tried the same test on humans, teaching subjects to associate the sight of a blue square with a shock. Using this therapy, they halted the humans' fear responses (measured in sweating) to the blue square. They were also able to retrain the people to fear a yellow square, but not the blue one. This sounds like something straight out of a dystopian 1970s movie, where giant computers would train humans to fear glowing blue squares and glowing yellow squares in order to force them to polish strangely bulbous plastic furniture.