Researchers Find a Way to Manipulate Memory

Researchers have found that memory can be easily manipulated. The study has wider implications in the field of criminal investigation.

The study results were based on a set of experiments conducted by a research team from Iowa State University, which found that memory can be changed using contradictory information.

"If you reactivate a memory by retrieving it, that memory becomes susceptible to changes again. And if at that time you give people new contradictory information, that can make the original memory much harder to retrieve later," said Jason Chan, an assistant professor of psychology at Iowa State, according to a news release.

However, memory once consolidated can't be easily modified, as researchers found that providing contradictory information after 48 hours had no effect on the original memory. According to Chan, there might be a six-hour period before the memory is consolidated. Also, information that doesn't confer with the original context of the memory has no effect on it.

"During that reconsolidation period, that's when the memory is easy to be interfered with. Once that window closes and that memory is stable again, if you get new information it should not interfere with that original memory," Chan said in a news release. "We found support for that idea in a number of experiments in which we varied the delay between the interfering memory or the misinformation and when people took that initial test."

The study findings have applications in criminal investigation, researchers said.

In one such experiment, study participants were shown an episode of the TV show "24". In this episode, a terrorist attacks a flight attendant with a hypodermic needle. During reactivation of memory, the participants were presented with an audio record of the episode with few manipulations. For example, in the audio version, the terrorist attacks the flight attendant with a stun gun.

Participants of the study who had recalled the use of a needle had a hard time remembering the detail during a test that was taken later, compared to people who hadn't remembered the needle the first time.

The study is published in the journal Proceedings of the National Academy of Sciences.