You can manipulate an existing memory simply by suggesting new or different information, Iowa State University researchers have shown.
The key is timing and recall of that memory, said Jason Chan, an assistant professor of psychology at Iowa State. “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,” Chan said.
One of the major findings from the studies is the impact on declarative memory — a memory that can be consciously recalled and verbally described, such as what you did last weekend. The effects are powerful because people are retrieving memory and then incorporating new information. Chan and Jessica LaPaglia, a graduate student at Iowa State, tested the impact of new information when presented at different time intervals after the retrieval of the original memory.