A team led by psychologist Elke Geraerts of the University of St. Andrews found differences in the “cognitive profiles” of people who spontaneously recall these traumatic incidents and people who recover such memories after prompting by suggestive therapeutic techniques. This may explain recent findings that spontaneously remembered incidents are much more likely to be corroborated by independent evidence than those induced by a therapist.

The researchers recruited 90 self-reported victims of childhood sexual abuse in the Netherlands for their study. Thirty of them recovered memories of the incident or incidents spontaneously; 30 did so during a therapy session; and 30 never forgot what happened. All of the participants — plus a control group of 30 people who reported no abuse – were given two standard false-memory tests.

The results were striking. “As a group, people who believed that they had recovered a memory of childhood sexual abuse through suggestive therapeutic techniques showed a pronounced tendency in incorrectly claim they had experienced events they had not really experienced, as measured by a simple cognitive test of false memory foundation,” the researchers report.

In contrast, those whose traumatic memories came spontaneously “showed no evidence of heightened susceptibility to false recall.”

To Geraerts and her colleagues, these findings suggest that memories recovered during therapeutic sessions “should be viewed with a cautious eye, as they may reflect the unwitting interaction of suggestive therapy with preexisting deficits in source memory.”

In the January issue of the journal Psychological Science, the researchers note there are “two radically different hypotheses for how recovered memory experiences come about,” and add their research suggests that “rather than being contradictory, perhaps the hypotheses reflect two different types of recovered-memory experiences.”

While noting that this work does not prove or disprove the accuracy of the memory of any individual person, they suggest that “clinicians who treat patients reporting recovered memories of childhood sexual abuse take care to examine the context of recovery and to consider its implications.”