Physiological, psychological and behavioral consequences of activating autobiographical memories

Activating an autobiographical memory for a specific childhood event can have immediate and robust physiological, psychological, and behavioral consequences. The target behavior was public speaking, a vital skill about which many people are socially anxious. In this study, it was suggested to subjects that they had a positive public speaking experience in early childhood; they then thought about and retrieved details of this true childhood memory. Compared to a control condition in which a different suggestion was made, subjects in the treatment group exhibited superior public speaking performance on the Trier Social Stress Test (TSST). Further, physiological measures of cortisol and a self-report measure of anxiety (STAI-S) reflected a significantly smaller increase in anxiety from before to after the TSST in the treatment than control condition. Activating autobiographical memory for an event increases the accessibility of that memory and consequently affects performance on related behaviors.     

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.     

Lasting false beliefs and their behavioral consequences

False beliefs and memories can affect people's attitudes, at least in the short term. But can they produce real changes in behavior? This study explored whether falsely suggesting to subjects that they had experienced a food-related event in their childhood would lead to a change in their behavior shortly after the suggestion and up to 4 months later. We falsely suggested to 180 subjects that, as children, they had gotten ill after eating egg salad. Results showed that, after this manipulation, a significant minority of subjects came to believe they had experienced this childhood event even though they had initially denied having experienced it. This newfound autobiographical belief was accompanied by the intent to avoid egg salad, and also by significantly reduced consumption of egg-salad sandwiches, both immediately and 4 months after the false suggestion. The false suggestion of a childhood event can lead to persistent false beliefs that have lasting behavioral consequences.     

Children remember childhood: implications for childhood amnesia

Whether events from early childhood are recalled as children grow older is a critical issue for understanding the development of autobiographical memory and the phenomenon of childhood amnesia. Sixteen white, middle-class 8-year-old children were asked about events that they had recalled in previous interviews when they were 40, 46, 58 or 70 months old. Children recalled most of the events about which they were asked, even those events that occurred in very early childhood. Moreover, children recalled the events accurately and with many details. However, children reported much new and different information about the events at age 8. Overall, girls recalled more information at age 8 than boys did. Surprisingly, there were no relationships between rehearsal and the amount of information children recalled at age 8, but it must be emphasized that all these events were frequently rehearsed at the time of occurrence. These results demonstrate remarkable memory over extended periods of time for events occurring in early childhood. Implications for childhood amnesia are discussed. © 1998 John Wiley & Sons, Ltd.     

False memories in women with self-reported childhood sexual abuse: an empirical study

Although controversy exists about the validity of memories of childhood abuse, little is known about memory function in individuals reporting childhood abuse. This study assessed memories for previously presented words, including the capacity for false memory of critical lures not actually present in the word list, in 63 subjects, including abused women with posttraumatic stress disorder (PTSD), abused women without PTSD, and men and women without abuse or PTSD. Abused women with PTSD had a higher frequency of false recognition memory of critical lures (95%) than abused women without PTSD (78%), nonabused women without PTSD (79%), or nonabused men without PTSD (86%). PTSD women also showed poorer memory for studied words and increased insertions of non-studied words other than critical lures. These findings are consistent with a broad range of memory alterations in abused women with PTSD.     

Absolut memory distortions: alcohol placebos influence the misinformation effect

Can the simple suggestion that you have consumed alcohol affect your memory for an event? Alcohol placebos affect social behaviors but not nonsocial ones, and have not previously been shown to affect memory. We investigated the effect of alcohol placebos using materials that revealed both the social and the nonsocial influences of memory Subjects drank plain tonic water, but half were told it was a vodka and tonic; then all subjects took part in an eyewitness memory experiment. Subjects who were told they drank alcohol were more swayed by misleading postevent information than were those who were told they drank tonic water, and were also more confident about the accuracy of their responses. Our results show that the mere suggestion of alcohol consumption may make subjects more susceptible to misleading information and inappropriately confident. These results also provide additional confirmation that eyewitness memory is influenced by both nonsocial and social factors.     

Strategies for verifying false autobiographical memories

This study examined the types of strategies people use to verify putative childhood memories and the degree to which their preferred strategies are restricted in typical memory implantation studies. We asked subjects to describe a situation in which they recalled a false childhood experience and a hypothetical situation in which they pretended to have developed a false memory after taking part in a memory implantation study. We also asked them how they did (or would) determine the source of the event. We found that subjects relied primarily on other people and cognitive strategies to verify their experiences. These results suggest that laboratory situations cultivate false memories in part because they prevent people from talking to others about the false event, which causes them to rely on less optimal strategies.     

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.     

Associative false recognition occurs without strategic criterion shifts

In the DRM (Deese/Roediger and McDermott) false memory paradigm, subjects studied lists of words associated with nonpresented critical words. They were tested in one of four instructional conditions. In a standard condition, subjects were not warned about the DRM Effect. In three other conditions, they were told to avoid false recognition of critical words. One group was warned before study of the lists (affecting encoding and retrieval processes), and two groups were warned after study (affecting only retrieval processes). Replicating prior work, the warning before study considerably reduced false recognition. The warning after study also reduced false recognition, but only when critical items had never been studied; when critical items were studied in half the lists so that subjects had to monitor memory for their presence or absence, the warning after study had little effect on false recognition. Because warned subjects were trying to avoid false recognition, the high levels of false recognition in the latter condition cannot be due to strategically guessing that critical test items were studied. False memories in the DRM paradigm are not caused by such liberal criterion shifts.     

Increased response time of primed associates following an “episodic” hypnotic amnesia suggestion: A case of unconscious volition

Following a hypnotic amnesia suggestion, highly hypnotically suggestible subjects may experience amnesia for events. Is there a failure to retrieve the material concerned from autobiographical (episodic) memory, or is it retrieved but blocked from consciousness? Highly hypnotically suggestible subjects produced free-associates to a list of concrete nouns. They were then given an amnesia suggestion for that episode followed by another free association list, which included 15 critical words that had been previously presented. If episodic retrieval for the first trial had been blocked, the responses on the second trial should still have been at least as fast as for the first trial. With semantic priming, they should be faster. In fact, they were on average half a second slower. This suggests that the material had been retrieved but blocked from consciousness. A goal-oriented information processing framework is outlined to interpret these and related data.     

The revelation effect for autobiographical memory: A mixture-model analysis

Participants provided information about their childhood by rating their confidence about whether they had experienced various events (e.g., “broke a window playing ball”). On some trials, participants unscrambled a key word from the event phrase (e.g., wdinwo—window) or an unrelated word (e.g., gnutge—nugget) before seeing the event and giving their confidence ratings. The act of unscrambling led participants to increase their confidence that the event occurred in their childhood, but only when the confidence rating immediately followed the act of unscrambling. This increase in confidence mirrors the “revelation effect” observed in word recognition experiments. In the present article, we analyzed our data using a new signal detection mixture distribution model that does not require the researcher to know the veracity of memory judgments a priori. Our analysis reveals that unscrambling a key word or an unrelated word affects response bias and discriminability in autobiographical memory tests in ways that are very similar to those that have been previously found for word recognition tasks.     

Validating reports of poor childhood memory

Recent evidence indicates that judgements about the quality of one's own childhood memory can be influenced experimentally, for example by manipulating ease of retrieval. This has led to the suggestion that judgements of poor memory made by clients in therapy may not be reliable. We therefore investigated whether individuals who judge themselves to have poor memory for their childhood do in fact score worse on a standardized test of autobiographical memory. Matched groups of individuals reporting poor and normal memory for childhood were administered the Autobiographical Memory Interview. Consistent with a previous study of neurological patients, subjective judgements were associated with performance on both personal semantic memory and autobiographical incident memory. Copyright © 2002 John Wiley & Sons, Ltd.     

Adult recollections of earliest childhood dreams: A cross-cultural study

In two studies, Caucasian and Asian college students recalled their earliest memory of a dream, and they provided information about behaviours and beliefs associated with dreaming. Consistent with previous research on childhood amnesia, participants rarely recounted dreams that occurred before age 3. In Study 1, the mean age of the earliest dream memory was 14 months earlier for Caucasians than for Asians. In Study 2, more Asians than Caucasians were unable to remember a childhood dream. Dream-related behaviours and beliefs also differed markedly across cultures. Compared to Asians, Caucasians reported talking more frequently with parents about their dreams in childhood, receiving stronger parental encouragement to share dreams, and feeling more comfortable doing so. Caucasians also reported sharing their dreams with others more frequently in adulthood and they assigned greater value to their dreams. Most Caucasians but few Asians consented to the researchers' request to send parents a questionnaire concerning the participant's childhood dreams. The results support the social interaction explanation for autobiographical memory development, in which parent–child conversations about the personal past contribute to memory accessibility.     

Posthypnotic amnesia for recently learned material: Interactions with “episodic” and “semantic” memory

In two experiments, posthypnotic amnesia was suggested for a word list memorized during hypnosis. After an initial test of amnesia the subjects gave word associations (Experiment 1) or category instances (Experiment 2) to stimuli intended to elicit the critical (word list) items covered by the amnesia. The extent of initial amnesia observed was strongly associated with measured hypnotic susceptibility. Even among the most hypnotizable subjects, however, the dense amnesia did not prevent the critical items from being elicited by the semantic memory tasks, nor did it modulate the priming which these associations received by virtue of the prior learning experience. Moreover, production of the critical items did not, in general, remind the amnesic subjects of those items which they had previously learned, but could not now remember. Full memory was restored after the amnesia suggestion was canceled by a prearranged cue. Posthypnotic amnesia appears to represent a temporary dissociation of episodic features from memory traces, so that the subject has difficulty in reconstructing the context in which the target events occurred.     

How pleasant was your childhood? Beliefs about memory shape inferences from experienced difficulty of recall

People's beliefs about how memory works can affect their inferences from experienced difficulty of recall. Participants were asked to recall either 4 childhood events (experienced as an easy task) or 12 childhood events (experienced as a difficult task). Subsequently, they were led to believe that either pleasant or unpleasant periods of one's life fade from memory. When the recall task was difficult (12 events), participants who believed that memories from unpleasant periods fade away rated their childhood as less happy than participants who believed that memories from pleasant periods fade away. The opposite pattern was observed when the recall task was easy (4 events). This interplay of recall experiences and memory beliefs suggests that the judgmental impact of subjective experiences is shaped by beliefs about their meaning. It also suggests that the recall difficulty in clinical memory work may lead a person to make negative inferences about his or her childhood, provided the person shares the popular belief that memory represses negative information.     

Adult recollections of earliest childhood dreams: a cross-cultural study

In two studies, Caucasian and Asian college students recalled their earliest memory of a dream, and they provided information about behaviours and beliefs associated with dreaming. Consistent with previous research on childhood amnesia, participants rarely recounted dreams that occurred before age 3. In Study 1, the mean age of the earliest dream memory was 14 months earlier for Caucasians than for Asians. In Study 2, more Asians than Caucasians were unable to remember a childhood dream. Dream-related behaviours and beliefs also differed markedly across cultures. Compared to Asians, Caucasians reported talking more frequently with parents about their dreams in childhood, receiving stronger parental encouragement to share dreams, and feeling more comfortable doing so. Caucasians also reported sharing their dreams with others more frequently in adulthood and they assigned greater value to their dreams. Most Caucasians but few Asians consented to the researchers' request to send parents a questionnaire concerning the participant's childhood dreams. The results support the social interaction explanation for autobiographical memory development, in which parent-child conversations about the personal past contribute to memory accessibility.     

When Knowing Becomes Remembering: Individual Differences in Susceptibility to Suggestion

In two experiments, the authors explored factors that might influence a person's tendency to make source-monitoring errors about autobiographical memories. In the first experiment, undergraduates retrieved a memory from childhood (a) that was known about but not remembered, (b) that was remembered, or (c) for which they were unsure of their memory's source. After writing down the memory, experimental groups listened to a guided visualization tape and answered questions about the event—interventions designed to help them focus on details of their memory. Controls also retrieved and wrote down a memory; however, instead of visualizing the memory, they were instructed to conduct a visual search task. Results indicated that guided visualization led participants to rate known memories closer to remembered events. A second experiment examined individual difference variables that might be related to this know-to-remember shift. Results indicated that extraversion, external locus of control, a memory that conveyed fear, and overall affective content predicted this rating. The applicability of these findings to the psychotherapy process is discussed.     

Creating false memories for events that occurred before versus after the offset of childhood amnesia

We examined whether false images and memories for childhood events are more likely when the event supposedly took place during the period of childhood amnesia. Over three interviews, participants recalled six events: five true and one false. Some participants were told that the false event happened when they were 2 years old (Age 2 group), while others were told that it happened when they were 10 years old (Age 10 group). We compared participants’ reports of the false event to their reports of a true event from the same age. Consistent with prior research on childhood amnesia, participants in the Age 10 group were more likely than participants in the Age 2 group to remember their true event and they reported more information about it. Participants in the Age 2 group, on the other hand, were more likely to develop false images and memories than participants in the Age 10 group. Furthermore, once a false image or memory developed, there were no age-related differences in the amount of information participants reported about the false event. We conclude that childhood amnesia increases our susceptibility to false suggestion, thus our results have implications for court cases where early memories are at issue.     

Creating false memories for events that occurred before versus after the offset of childhood amnesia

We examined whether false images and memories for childhood events are more likely when the event supposedly took place during the period of childhood amnesia. Over three interviews, participants recalled six events: five true and one false. Some participants were told that the false event happened when they were 2 years old (Age 2 group), while others were told that it happened when they were 10 years old (Age 10 group). We compared participants' reports of the false event to their reports of a true event from the same age. Consistent with prior research on childhood amnesia, participants in the Age 10 group were more likely than participants in the Age 2 group to remember their true event and they reported more information about it. Participants in the Age 2 group, on the other hand, were more likely to develop false images and memories than participants in the Age 10 group. Furthermore, once a false image or memory developed, there were no age-related differences in the amount of information participants reported about the false event. We conclude that childhood amnesia increases our susceptibility to false suggestion, thus our results have implications for court cases where early memories are at issue.     

Remembering when we last remembered our childhood experiences: Effects of age and context on retrospective metamemory judgments

People sometimes exhibit a ‘forgot‐it‐all‐along bias’ in which they claim that they have gone for months or years without thinking about certain childhood experiences despite recently recalling those memories. The present study examines memory for memories of childhood experiences, expanding on prior work by using manipulations that require greater reflection when thinking about remembered experiences and when making retrospective metamemory judgments. Age‐related differences in memory‐for‐memory accuracy were also examined. Young (18–20) and older adults (63–89) recalled various events while focusing on emotional or perceptual details for some, and several weeks later were asked to indicate the last time they had remembered various events. Results showed that young adults were more accurate than older adults overall, though both age groups still exhibited a forgot‐it‐all‐along bias that was reduced but not eliminated when a contextual reminder was provided. Copyright © 2008 John Wiley & Sons, Ltd.