From MSNBC News:
People who believe they have lived past lives as, say, Indian princesses or battlefield commanders are more likely to make certain types of memory errors, according to a new study. The propensity to make these mistakes could, in part, explain why people cling to implausible reincarnation claims in the first place. Researchers recruited people who, after undergoing hypnotic therapy, had come to believe that they had past lives.
Subjects were asked to read aloud a list of 40 non-famous names, and then, after a two-hour wait, told that they were going to see a list consisting of three types of names: non-famous names they had already seen (from the earlier list), famous names, and names of non-famous people that they had not previously seen. Their task was to identify which names were famous.
The researchers found that, compared to control subjects who dismissed the idea of reincarnation, past-life believers were almost twice as likely to misidentify names. In particular, their tendency was to wrongly identify as famous the non-famous names they had seen in the first task. This kind of error, called a source-monitoring error, indicates that a person has difficulty recognizing where a memory came from.
More here.