Ghetti, S. & Castelli, P. (2006). Developmental differences in false-event rejection: Effects of memorability-based warnings. Memory, 14, 762-776.
Background
This article comes from a recent special issue of Memory devoted to memory editing mechanisms. In this article, Ghetti and Castelli describe what they call the memorability-based strategy (MBS). Basically, the memorability-based strategy involves making use of knowledge of how memorable an event should be if it really happened, to make an inference about the events occurrence. If an event is one that should be highly memorable, and yet, one finds it difficult to remember, a reasonable inference is that it did not occur (e.g., “If that had happened, I would have remembered it”). If an event is one that should not be highly memorable, and one finds it difficult to remember, the inference is less clear. It’s possible that the event did not happen, or its possible that the event did happen and it was merely forgotten. The memorability-based strategy leads to the prediction that it should be more difficult to create false memories for events that one would expect to be highly memorable. In prior work, Ghetti and colleagues have found that use of the memorability-based strategy does not really develop until children are about 9 years old.
Ghetti and Castelli consider a few possible explanations for this late development. One possibility is that children younger than 9-years-old have a “production deficiency”. That is, they are able to use the strategy, but they do not think of using t on their own without being prompted. A second possibility is that younger children are “utilisationally deficient”. That is, they may try to use the strategy but they aren’t very good at using it. A third possibility is that younger children are “mediationally deficient”. That is, they lack the cognitive skills to use the strategy, for instance, being unable to set different response criterion for different types of items. So the purpose of the research reported in their article was to determine whether the use of the MBS could be primed in children by providing them with warnings about event memorability.
Methodology
Children were five, seven, and nine years old. They were interviewed about four false events and four true events. Two of the false events were events that should be highly memorable and two of the false events were events that should not be highly memorable. Similarly, two of the true events were events that should be highly memorable and two of the true events were events that should not be highly memorable.
In all conditions children were interviewed about four true and four false events (randomly ordered), with two of each being highly memorable and two of each being less memorable. Children were told that their parents had told the experimenter about the event, and children were asked to provide the details they remembered from the event. After each event, children were asked to rate their confidence that the event happened or did not happen, and were asked to rate the amount of detail they recalled from the event. Following all the events, participants were told that some of the events had not actually occurred. Each event was then described again and children were asked to indicate for each one whether or not they believed it occurred.
Children were placed in one of three conditions.
· No Warning Condition: Children were told nothing about the memorability of the events.
· Memorability Congruent Condition: Children were correctly told prior to each event that the high memorability events were the type of events that most children find easy to remember, and that the low memorability events were the type of events that most children found difficult to remember. More specifically, they were told that failure to remember a high memorability event suggests that the event did not happen, whereas failure to remember a low memorability event does not necessarily mean the event did not happen.
· Memorability Incongruent Condition: Children were incorrectly told prior to each event that the low memorability events were the type of events that most children find easy to remember, and that the high memorability events were the type of events that most children found difficult to remember. More specifically, they were told that failure to remember a low memorability event suggests that the event did not happen, whereas failure to remember a high memorability event does not necessarily mean the event did not happen.
What might one expect from this experiment? First, nine year old children should have fewer false memories for high memorability false events regardless of condition. This is based on prior research showing that nine-year olds spontaneously make use of the MBS. Younger children should not show any evidence of the MBS in the no warning condition. However, if younger children have a “production deficiency”, then they should show evidence of the MBS in the memorability congruent condition, but not the other two conditions.
Results
· Consistent with prior research, only 9-year-olds rejected more high memorability events than low memorability events. This means they were using the MBS, just like prior research has shown.
· The memorability congruent condition led to more rejections of high memorability false events for seven-year-olds. This effect did not occur for low memorability false events.
· The memorability incongruent condition eliminated the MBS effect in nine-year-olds.
· Seven-year-olds trusted their event rejections more in the memory congruent condition. Five-year-olds trusted their judgments less. Warning had no effect on confidence in nin-year-olds
· When children were told that some of the events were false, nine-year-olds were the only age group to show evidence of the MBS. Both warning conditions resulted in lower false memory rates for 5-year-olds when compared to the control condition.
Discussion
The memorability based strategy involves three components: (1) Knowledge of an event’s expected memorability, (2) Knowledge of whether or not the event is being remembered, (3) an inference that if a high memorability event is not remembered, then it probably didn’t happen. Young children do not appear to make use of the MBS. The present results suggest that 7-year-olds may have some limited ability to make use of the MBS when specifically instructed to do so. Even 7-year-olds showed only a limited ability to make use of MBS when instructed to.
Important Legal Disclaimer: The preceding are articles we read together in the Lampinen Lab Fall 2006 false memory reading group. By clicking on the authors’ names of each article you can see the summary of that article. The summary was prepared by the student presenting that article and it is of course the case that the views expressed in the summary do not necessarily represent the views of the reading group as a whole, Dr. Lampinen, the Lampinen Lab, the University of Arkansas, the Razorback Football or Basketball teams (although we're not sure about cross country), people living down the street from us, Bob Dylan, Jack Fate, our extended families, or anyone else for that matter except for the student who wrote the summary (and they don't necessarily believe what they wrote either).