So that's why I don't remember: Normalising forgetting of childhood events influences false autobiographical beliefs but not memories

We investigated changes in autobiographical belief and memory ratings for childhood events, after informing individuals that forgetting childhood events is common. Participants received false prevalence information (indicating that a particular childhood event occurred frequently in the population) plus a rationale normalising the forgetting of childhood events; false prevalence information alone; or no manipulation, for one (Study 1) or two (Study 2) unlikely childhood events. Results demonstrated that combining prevalence information and the “forgetting rationale” substantially influenced autobiographical belief ratings, whereas prevalence information alone had no impact (Study 1) or a significantly lesser impact (Study 2) on belief ratings. Prevalence information consistently impacted plausibility ratings. No changes in memory ratings were observed. These results provide further support for a nested relationship between judgements of plausibility, belief, and memory in evaluating the occurrence of autobiographical events. Furthermore, the results suggest that some purported false memory phenomena may instead reflect the development of autobiographical false beliefs in the absence of memory.     

When plausibility manipulations work: An examination of their role in the development of false beliefs and memories

In the current study we examined whether prevalence information and imagery encoding influence participants' general plausibility, personal plausibility, belief, and memory ratings for suggested childhood events. Results showed decreases in general and personal plausibility ratings for low prevalence events when encoding instructions were not elaborate; however, instructions to repeatedly imagine suggested events elicited personal plausibility increases for low-prevalence events, evidence that elaborate imagery negated the effect of our prevalence manipulation. We found no evidence of imagination inflation or false memory construction. We discuss critical differences in researchers' manipulations of plausibility and imagery that may influence results of false memory studies in the literature. In future research investigators should focus on the specific nature of encoding instructions when examining the development of false memories.     

Imagination equally influences false memories of high and low plausibility events

To examine the effects of event plausibility on people's false beliefs and memories for imagined childhood events, subjects took part in a three‐stage procedure. First, subjects rated how confident they were that they had experienced certain childhood events. They also rated their memories of the events. Second, 1 week later, subjects imagined one high, one moderate and one low plausibility event. Third, 1 week later (and 2 weeks after their initial ratings), subjects rated their confidence and memory a second time. Imagining the events made subjects more confident that they were genuine experiences and gave subjects clearer and more complete memories. Plausibility did not affect subjects' confidence but it did affect their memories. Subjects developed clearer and more complete memories for high, followed by moderate, followed by low plausibility events regardless of whether those events were imagined. We use a nested model of plausibility, belief and memory to discuss our findings. Copyright © 2008 John Wiley & Sons, Ltd.     

Changing beliefs about implausible autobiographical events: a little plausibility goes a long way

Three experiments investigated the malleability of perceived plausibility and the subjective likelihood of occurrence of plausible and implausible events among participants who had no recollection of experiencing them. In Experiment 1, a plausibility-enhancing manipulation (reading accounts of the occurrence of events) combined with a personalized suggestion increased the perceived plausibility of the implausible event, as well as participants' ratings of the likelihood that they had experienced it. Plausibility and likelihood ratings were uncorrelated. Subsequent studies showed that the plausibility manipulation alone was sufficient to increase likelihood ratings but only if the accounts that participants read were set in a contemporary context. These data suggest that false autobiographical beliefs can be induced in clinical and forensic contexts even for initially implausible events.     

Liar,liar: Consistent lying decreases belief in the truth

This study investigated the effects of lying on belief ratings for autobiographical childhood events. Participants lied by trying to convince the experimenter that likely events had not happened and that unlikely events had happened. Participants consistently lied, consistently told the truth, and alternated lying and truth telling across two sessions. Results showed that consistent false assents increased belief in those false events and that consistent false denials decreased belief in those true events. False denials had a larger influence on belief than did false assents. False assents that were told first were more likely to increase in belief than were false assents told in the second session. False denials decreased belief in the true event regardless of when they were told. These results suggest that lying influences confidence ratings both by increasing belief in a lied‐about event and by decreasing belief in a true event.     

Is knowing believing? The role of event plausibility and background knowledge in planting false beliefs about the personal past

False memories are more likely to be planted for plausible than for implausible events, but does just knowing about an implausible event make individuals more likely to think that the event happened to them? Two experiments assessed the independent contributions of plausibility and background knowledge to planting false beliefs. In Experiment 1, subjects rated 20 childhood events as to the likelihood of each event having happened to them. The list included the implausible target event “received an enema,” a critical target event of Pezdek, Finger, and Hodge (1997). Two weeks later, subjects were presented with (1) information regarding the high prevalence rate of enemas; (2) background information on how to administer an enema; (3) neither type of information; or (4) both. Immediately or 2 weeks later, they rated the 20 childhood events again. Only plausibility significantly increased occurrence ratings. In Experiment 2, the target event was changed from “barium enema administered in a hospital” to “home enema for constipation”; significant effects of both plausibility and background knowledge resulted. The results suggest that providing background knowledge can increase beliefs about personal events, but that its impact is limited by the extent of the individual’s familiarity with the context of the suggested target event.     

Indirect cueing elicits distinct types of autobiographical event representations

Studies that distinguish among believed memories, believed-not-remembered events (e.g., family stories), and nonbelieved memories (i.e., memories no longer believed to have occurred) typically rely on experimenter provided or overtly elicited events. These methods may mis-estimate the frequency and nature of such events in everyday memory. Three studies examined whether such events would be elicited via indirect cueing. Participants recalled and rated events on autobiographical belief, recollection, and other characteristics associated with remembering. All three event types resulted, but with a low rate of nonbelieved memories. Believed and nonbelieved memories received similar perceptual and re-experiencing ratings, and both exceeded believed-not-remembered events. Lifespan cueing found nonbelieved memories to be most frequent in middle childhood (ages 6–11). Cueing for “events” vs. “memories” revealed that “memory” cues lead to retrieval of a more homogeneous set of events and differences when predicting autobiographical belief and recollection. These studies support the distinction between autobiographical belief and recollection for autobiographical events.     

Digitally manipulating memory: Effects of doctored videos and imagination in distorting beliefs and memories

In prior research on false autobiographical beliefs and memories, subjects have been asked to imagine fictional events and have been exposed to false evidence that indicates that the fictional events occurred. But what are the relative contributions of imagination and false evidence toward false belief and memory construction? In the present study, subjects observed and copied various simple actions; then they viewed doctored videos that suggested that they had performed extra actions and they imagined performing some of those and some other actions. Subjects returned 2 weeks later for a memory test. False evidence or imagination alone was often sufficient to cause belief and memory distortions; in combination, they appeared to have additive or even superadditive effects. The results bear on the mechanisms underlying false beliefs and memories, and we propose legal and clinical applications of these findings.     

Memory for autobiographical facts and events: a comparison of women reporting childhood sexual abuse and non‐abused controls

Although there is evidence that many adult survivors of childhood sexual abuse (CSA) have a period when they forget their abuse, existing research is equivocal about whether such individuals show other autobiographical memory impairments. The present study addressed some of the sampling and measurement problems apparent in previous studies and compared 74 women reporting a history of CSA with 60 non‐abused controls on their ability to recall facts and events from childhood. The results showed that the CSA group did not differ from the controls in the quality of their memories for autobiographical incidents. However, they were significantly less able than controls to recall specific facts about their personal history, such as significant addresses and names of significant individuals, after controlling for educational level, depression and childhood address changes. CSA group participants reporting a period of abuse forgetting appeared more impaired than those with continuous abuse memories in their recall of personal semantic facts, but were similar in their recall of autobiographical incidents. The findings suggest that experiencing a period of abuse forgetting is a more influential factor in predicting the ability to recall personal semantic facts than abuse status alone. Copyright © 2002 John Wiley & Sons, Ltd.     

Personalized and not general suggestion produces false autobiographical memories and suggestion-consistent behavior

Suggesting false childhood events produces false autobiographical beliefs, memories and suggestion-consistent behavior. The mechanisms by which suggestion affects behavior are not understood, and whether false beliefs and memories are necessary for suggestions to impact behavior remains unexplored. We examined the relative effects of providing a personalized suggestion (suggesting that an event occurred to the person in the past), and/or a general suggestion (suggesting that an event happened to others in the past). Participants (N=122) received a personalized suggestion, a general suggestion, both or neither, about childhood illness due to spoiled peach yogurt. The personalized suggestion resulted in false beliefs, false memories, and suggestion-consistent behavioral intentions immediately after the suggestion. One week or one month later participants completed a taste test that involved eating varieties of crackers and yogurts. The personalized suggestion led to reduced consumption of only peach yogurt, and those who reported a false memory showed the most eating suppression. This effect on behavior was equally strong after one week and one month, showing a long lived influence of the personalized suggestion. The general suggestion showed no effects. Suggestions that convey personal information about a past event produce false autobiographical memories, which in turn impact behavior.     

Remembering the past and imagining the future: examining the consequences of mental time travel on memory

Cognitive, neuropsychological, and neuroimaging evidence suggests that remembering the past and imagining the future rely on overlapping processes in episodic memory. The three experiments reported here examine the consequences of remembering the past and imagining the future on the accessibility of other information in memory. Participants first studied events associated with a specific context and then either (a) retrieved past autobiographical events associated with that same context or (b) imagined future autobiographical events associated with that same context. Replicating and extending evidence of retrieval-induced forgetting, remembering autobiographical events from the past caused participants to forget the related studied events. However, imagining future autobiographical events failed to cause participants to forget the related studied events. These results suggest an important difference in the memorial consequences of remembering and imagining.     

Remembering the past and imagining the future: Examining the consequences of mental time travel on memory

Cognitive, neuropsychological, and neuroimaging evidence suggests that remembering the past and imagining the future rely on overlapping processes in episodic memory. The three experiments reported here examine the consequences of remembering the past and imagining the future on the accessibility of other information in memory. Participants first studied events associated with a specific context and then either (a) retrieved past autobiographical events associated with that same context or (b) imagined future autobiographical events associated with that same context. Replicating and extending evidence of retrieval-induced forgetting, remembering autobiographical events from the past caused participants to forget the related studied events. However, imagining future autobiographical events failed to cause participants to forget the related studied events. These results suggest an important difference in the memorial consequences of remembering and imagining.     

The effects of photographs and event plausibility in creating false beliefs

Recent studies have shown that using photographs as memory retrieval aids can significantly increase the likelihood of false memories. The current study further investigated this effect by examining the interactive effects of photographs and event plausibility in developing false beliefs. At Time 1 and two weeks later at Time 2, participants rated 20 events on the Life Events Inventory (LEI) as to whether each occurred to them in childhood. One week after Time 1, participants were told that two target events were plausible and two were implausible. They then used event-related photographs to visualize one plausible and one implausible event. Occurrence ratings significantly increased from Time 1 to Time 2 for plausible events in the photo condition. These results suggest that the use of photographs as a memory enhancing technique is unlikely to cause false memories for events that are not perceived personally plausible.     

The consequences of suggesting false childhood food events

We combined data across eight published experiments (N = 1369) to examine the formation and consequences of false autobiographical beliefs and memories. Our path models revealed that the formation of false autobiographical belief fully mediated the pathway between suggesting to people that they had experienced a positive or negative food-related event in the past and current preference for that food. Suggestion indirectly affected intention to eat the food via change in autobiographical belief. The development of belief with and without memory produced similar changes in food preferences and behavior intention, indicating that belief in the event drives changes in suggestion-related attitudes. Finally, positive suggestions (e.g., “you loved asparagus the first time you tried it”) yielded stronger effects than negative suggestions (e.g., “you got sick eating egg salad”). These findings show that false autobiographical suggestions lead to the development of autobiographical beliefs, which in turn, have consequences for one's attitudes and behaviors.