ITHACA, N.Y. -- When preschool children were asked weekly about whether afictitious event had ever happened to them, more than half the 3- and4-year-old children by the tenth week reported that it had and providedcogent details, according to a Cornell University study.

Even more surprising, however, is that more than one-quarter of thechildren could not be convinced the event never occurred when theresearchers and their parents explained that the events never occurred.Furthermore, professionals who specialize in interviewing children couldnot distinguish between children telling false or true accounts when theywere shown videotapes of the children's "recollections."

"When young children, ages 3 and 4, are questioned by neutral interviewers,they do very well. They recall events with 90 percent accuracy," saidStephen J. Ceci, Ph.D., the Helen L. Carr Professor of Psychology inCornell's College of Human Ecology who led the study.

"However, when children are repeatedly interviewed over the course of weeksand months with misleading suggestions -- which sometimes occurs inforensic cases -- many come to remember the false events as true andprovide detailed and coherent narratives about these false events," saidCeci, whose interviewers asked children, for example: "Think real hard.Did you ever get your hand caught in a mousetrap and go to the hospital toget it off?"

"So compelling did the children's narratives appear that we suspected thatsome of the children had come to truly believe they had experienced thefictitious events. Neither parents nor researchers were able to convince27 percent of the children that the events never happened," said Ceci, awell-known research developmental psychologist who has been studying thesuggestibility of children's memories for more than a decade.

With Cornell colleague Mary LynCrotteau Huffman, Ph.D., Ceci reported hisfindings on how suggestible the memories of preschool children are in theJuly issue of the Journal of the American Academy of Child and AdolescentPsychiatry (36:7, July 1997).

"These false beliefs or false memories appear to arise when children forgetthe basis of an event's familiarity," said Ceci, co-author of the book,Jeopardy in the Courtroom: A Scientific Analysis of Children's Testimony(American Psychological Association, 1996). "Young children are especiallyprone to what we call 'source amnesia.'"

Ceci suggests that when children are asked to think periodically about afictitious event, they imagine a fictitious scenario, initially rejectingits authenticity because it is unfamiliar. Weeks later, when asked aboutit again, however, they may falsely accept the event's validity because itis now familiar as a result of having imagined the scenario earlier.

"Consequently, it is exceedingly, devilishly difficult for professionals totell fact from fiction when a child has been repeatedly suggestivelyinterviewed over a long period of time," Ceci said. "These childrenfrequently display none of the indicators of lying or tricking; they lookand act the way children do when they are trying to be accurate and honest."

These findings have important implications for cases involving youngchildren, including those related to child abuse and sexual child abusebecause in some of these trials children are interviewed many times overthe course of weeks, months, or even years. In fact, the average child inthe courtroom is interviewed formally 3.5 to 11 times before a courtappearance and many more times informally.

"When suggestive interviewing techniques are used, as in these studies andin real cases, they lead to high levels of correct disclosure when thechild actually experienced the event in question," Ceci pointed out."However, the problem is that they also lead to high levels of false assentwhen the event was not experienced."

The studies were supported, in part, by a grant from the National ScienceFoundation.