Childhood amnesia: Empirical evidence for a two-stage phenomenon

The term childhood amnesia refers to the inability of adults to remember events from their infancy and early childhood. If we plot the number of memories that adults can recall as a function of age during childhood, the number of memories reported increases gradually as a function of age. Typically, this finding has been used to argue that gradual changes in memory development contribute to a gradual decline in childhood amnesia during the preschool period. Alternatively, it is possible that pooling data across participants has obscured more abrupt, stage-like changes in the remission of childhood amnesia. In the present study we examined the number and distribution of childhood memories for individual participants. Six adults were repeatedly interviewed about their childhood memories. We found that the distribution of adults' early childhood memories may be less continuous than pooled data suggest. This finding has important implications for current explanations of childhood amnesia.     

Children dating childhood memories

How accurate are children when dating very long-term memories? Chinese and European Canadian 8-, 11-, and 14-year-olds (N=344) recalled and dated memories from before they went to school in a memory fluency task. Parents provided verification of children's memories and age estimates. Across all age and culture groups, a telescoping effect (i.e., events were dated as taking place more recently than they actually did) was found for earlier memories (before 48 months) and a reverse telescoping effect for later memories (after 48 months). Older children showed a greater tendency to telescope earlier memories and a weaker tendency to reverse telescope later memories than did younger children. Euro-Canadian children showed larger reverse telescoping than Chinese children. These are the first systematic findings concerning the accuracy of children's dating of very long-term memories. They shed new light on the phenomenon of telescoping and have implications for research on childhood amnesia.     

Remembering the past and imagining the future: A role for nonvisual imagery in the everyday cognition of blind and sighted people

Past research has associated depression with memory biases pertaining to the frequency, duration, and specificity of past events. Associations have been proposed between both negative and positive memory biases and depression symptoms. However, research has not examined the occurrence of actual events over time in the study of memory bias. To address these limitations and investigate whether a negative or positive memory bias is associated with symptoms of depression, we collected weekly data on specific types of life events over a 4-year period from a sample of college students, and asked students to recall event frequency at the end of that period. Exaggerated recall of frequency for positive events but not other types of events was associated with depression symptoms, using both continuous and categorical measures. Moderator analyses indicated that these effects were evidenced primarily for memories involving the self and among individuals low in trait self-enhancement. The current study indicates that positive memory-frequency bias is an important type of memory bias associated with symptoms of depression. Results support the idea that the link between memory bias for positive event frequency and depressed mood arises out of a current-self vs past-self comparison.     

Phenomenology of autobiographical memories: The Memory Experiences Questionnaire

The phenomenology of autobiographical memories varies on a number of dimensions: some memories are vivid and others dim; some are emotionally intense and others lack emotional content. The present research sought to develop a psychometrically-sound scale to assess the entire range of dimensions on which autobiographical memories differ. We reviewed the literature on memory experiences and identified 10 relevant dimensions: Vividness, Coherence, Accessibility, Time Perspective, Sensory Details, Visual Perspective, Emotional Intensity, Sharing, Distancing, and Valence. We constructed a comprehensive item pool to assess these dimensions and, using data from several large samples (Ns=941; 510; 212), we showed that: (a) all 10 scales had adequate reliability (median alpha=.87; range=.72 to .97), (b) the 10-factor structure provided a good fit to the data, and (c) gender, personality, and memory recency had theoretically meaningful relations with the 10 scales. For example, gender and ethnicity differences in phenomenology were mediated by memory content, and early and recent memories had distinct phenomenologies. The discussion focuses on the theoretical and practical utility of the 10 scales.     

Strategic grouping in the spatial span memory task

Spatial short-term memory performance was examined in relation to participants’ strategies. A total of 20 adult participants viewed and reproduced sequences of locations that varied in length (five, six, seven, or eight locations) and spatial separability (a manipulation of the configurations). In trial-by-trial self-reports, participants described five types of strategies. Chunking the spatial sequences into groups of three or four locations was the sole strategy associated with increased accuracy. Participants demonstrated considerable variability in the strategies that they selected, suggesting that cognitive resources are allocated to strategy selection, execution, and monitoring in the spatial span task. Spatially separable sequences were more accurately recalled than nonseparable sequences, independent of strategic grouping, suggesting two levels of grouping in the spatial span task.     

The role of working memory capacity in autobiographical retrieval: Individual differences in strategic search

Remembering previous experiences from one's personal past is a principal component of psychological well-being, personality, sense of self, decision making, and planning for the future. In the current study the ability to search for autobiographical information in memory was examined by having college students recall their Facebook friends. Individual differences in working memory capacity manifested itself in the search of autobiographical memory by way of the total number of friends remembered, the number of clusters of friends, size of clusters, and the speed with which participants could output their friends' names. Although working memory capacity was related to the ability to search autobiographical memory, participants did not differ in the manner in which they approached the search and used contextual cues to help query their memories. These results corroborate recent theorising, which suggests that working memory is a necessary component of self-generating contextual cues to strategically search memory for autobiographical information.     

Keeping an eye on the truth? Pupil size changes associated with recognition memory

During recognition memory tests participants' pupils dilate more when they view old items compared to novel items. We sought to replicate this “pupil old/new effect” and to determine its relationship to participants' responses. We compared changes in pupil size during recognition when participants were given standard recognition memory instructions, instructions to feign amnesia, and instructions to report all items as new. Participants' pupils dilated more to old items compared to new items under all three instruction conditions. This finding suggests that the increase in pupil size that occurs when participants encounter previously studied items is not under conscious control. Given that pupil size can be reliably and simply measured, the pupil old/new effect may have potential in clinical settings as a means for determining whether patients are feigning memory loss.     

TV or not TV? Does the immediacy of viewing images of a momentous news event affect the quality and stability of flashbulb memories?

The flashbulb accounts of 38 participants concerning the September 11th 2001 terrorist attack reported at both 28 hours and 6 months following the event were examined for quantity, quality, and consistency as a function of the time lapse between first learning of the event and initial viewing of media images. The flashbulb accounts of those who reported seeing images at least an hour after learning of the event differed qualitatively, but not quantitatively, from accounts of participants who reported seeing images at the same time as or within minutes of learning of the event. Delayed viewing of images resulted in less elaborate and generally less consistent accounts across the 6-month interval. The results are discussed in terms of factors affecting flashbulb memory formation and individual differences in connectedness to the event.     

Remembering all that and then some: Recollection of autobiographical memories after a 1-year delay

We have previously shown that repeated retrievals of remote autobiographical memories over the course of one month led to an overall increase in reported detail (Nadel, Campbell, & Ryan, 2007). The current study examined the retrieval of those same memories 1 year later in order to determine whether the level of detail remained stable or whether the memories returned to their original state. Participants reported even more details than they had recalled at least 1 year earlier, including new details that were reported for the first time. This finding was consistent across both multiple and single retrieval conditions, suggesting that the critical factor leading to the increase in recall was the passage of time. These findings provide evidence for long-term effects of repeated retrieval on memory content.