Aging Memory Research Articles

Benchmarking the past: Children's early memories and maternal reminiscing as a function of family structure

The present research explores the role of family structure and maternal reminiscing in childhood amnesia in middle childhood (age 7–11 years). Children from non-nuclear (solo parent, blended, extended; n=13) or nuclear families (two biological parents; n=13) were interviewed about their two earliest memories; they also reminisced with their mothers about shared past events. Children from non-nuclear families had earlier memories than children from nuclear families. Mothers from non-nuclear families generated shorter and less elaborative reminiscing conversations with their children than did mothers from nuclear families. For children from non-nuclear families, the number of extra adults in their household was correlated with earlier memories. Results are discussed with respect to both transition and social–cultural theories of memory development.

A complementary processes account of the development of childhood amnesia and a personal past.

Personal-episodic or autobiographical memories are an important source of evidence for continuity of self over time. Numerous studies conducted with adults have revealed a relative paucity of personal-episodic or autobiographical memories of events from the first 3 to 4 years of life, with a seemingly gradual increase in the number of memories until approximately age 7 years, after which an adult distribution has been assumed. Historically, this so-called infantile amnesia or childhood amnesia has been attributed either to late development of personal-episodic or autobiographical memory (implying its absence in the early years of life) or to an emotional, cognitive, or linguistic event that renders early autobiographical memories inaccessible to later recollection. However, neither type of explanation alone can fully account for the shape of the distribution of autobiographical memories early in life. In contrast, the complementary processes account developed in this article acknowledges early, gradual development of the ability to form, retain, and later retrieve memories of personally relevant past events, as well as an accelerated rate of forgetting in childhood relative to adulthood. The adult distribution of memories is achieved as (a) the quality of memory traces increases, through addition of more, better elaborated, and more tightly integrated personal-episodic or autobiographical features; and (b) the vulnerability of mnemonic traces decreases, as a result of more efficient and effective neural, cognitive, and specifically mnemonic processes, thus slowing the rate of forgetting. The perspective brings order to an array of findings from the adult and developmental literatures.

Rolling amnesia and the omnivorous now

Throughout his career, New York-based experimental filmmaker and animator Jeff Scher has created animated works that are in dialogue with the diary film tradition in avant-garde cinema. Scher uses his distinctive single-frame rotoscope and collage animation technique to investigate the selective nature of memory and to celebrate the moments that constitute everyday life. Scher’s animated trilogy, You Won’t Remember This (2007), You Won’t Remember This Either (2009), and You Might Remember This (2011), depicts a series of everyday moments in the early childhoods of his two sons Buster and Oscar. The trilogy is centred on the mnemonic phenomenon that is referred to in developmental and cognitive psychology as childhood amnesia, which has presented problems for the philosophy of memory since John Locke first investigated the roles of memory and consciousness in the constitution of the identity of the self. Scher’s three portraits invite spectators to reflect on the mnemonic imbalance that is specific to this particular temporal situation—where the parent is able to remember what the child will ultimately forget—in both a distilled and heightened way. This paper investigates the ways in which the rotoscope collage technique employed by Scher in the You Won’t Remember This trilogy not only endows the works with a special capacity to emphasise the universal nature of childhood amnesia but also, conversely, resembles the phenomenological experience of remembering itself.

The magic shrinking machine revisited: The presence of props at recall facilitates memory in 3-year-olds.

In a seminal study Simcock and Hayne (2002) showed that 3-year-olds were unable to use newly acquired words to describe a "magic" event experienced 6 or 12 months earlier. In the reference study the children's verbal recall was tested without props being present. Inspired by recent evidence, the original design was replicated, testing 33-and 39-month-olds (n = 180), but with props present at recall while controlling for potential online reasoning. The results revealed that the children did use newly acquired words to describe their preverbal memory. Thus, the present study shows that nonverbal memories can be verbalized if the recall setting provides a high level of contextual support, a finding relevant to researchers investigating the offset of childhood amnesia.

Using the context preexposure facilitation effect to study long-term context memory in preweanling, juvenile, adolescent, and adult rats

The present study used the context preexposure facilitation effect (CPFE) to examine long-term retention of incidental context learning in periweanling, adolescent and adult rats. The CPFE is a variant of contextual fear conditioning in which encoding the context representation, associating this representation with shock, and expressing the context–shock association each occur on separate occasions. Experiment 1 manipulated the retention interval—1d, 8d, 15d, or 22d—between context preexposure and training with immediate shock to determine how long the encoded context could be remembered (testing always occurred 24h following training). The other factors were age—postnatal day (PND) 24 vs 31—and training group—Preexposed to the training context (Pre) vs. an alternate context (Alt-Pre). At both ages, significantly more freezing was evident in the Pre vs. Alt Pre Groups at the 24h, 8d and 15d retention intervals but not at the 22d interval, indicating that juvenile–adolescent rats remember the context for up to 15d. In contrast, context memory persists for 22days in adult rats (Experiment 2); and is not evident after 24h, 8d, or 15d retention intervals in PND 17 rats (Experiment 3). The present study illustrates the value of the CPFE paradigm for investigations of long-term context memory in developing rats. Implications for the neurobiology of infantile amnesia are discussed.

Autobiographical memory in ADHD subtypes

Background Episodic autobiographical memory (EAM) has not been extensively investigated in children with attention-deficit/hyperactivity disorder (ADHD). The objective of this study was to examine EAM in school-age children with ADHD in reference to the encoding period: recent memories (previous school years) and remote memories (first years of life).Methods A sample of 29 children with ADHD and 29 typically developing children, matched for age and gender, completed a questionnaire to assess EAM. These participants were recruited from an initial sample of 572 participants. Developmental differences in accessing and recalling specific personal events and episodic details in groups with ADHD were predicted.Results The control group showed a typical trend of EAM with fewer remote and episodic memories than recent ones. The ADHD groups showed a general EAM deficit. More precisely, the ADHD-I group performed equally poorly on remote and recent EAMs, whereas the ADHD-C group showed a higher number of remote EAMs than recent ones.Conclusions The findings suggest that EAM can be impaired in children with ADHD. Clinical and medicolegal implications of these results and the relation between age and childhood amnesia are discussed.

Relearning a context-shock association after forgetting is an NMDAr-independent process

Infantile amnesia (i.e., the rapid rate of forgetting in young animals) is at least partially due to a memory retrieval, rather than a storage, failure as studies have shown that these engrams can continue to influence later behavior. For example, prior conditioning affects the neural mechanisms underlying future learning. In adult animals, the initial learning of a context-shock association depends upon N-Methyl-D-Aspartate (NMDA) receptors, but this conditioning renders subsequent learning to a similar context NMDAr-independent. In the present study, we examined whether this transition from NMDAr-dependent to NMDAr-independent context conditioning occurs even after infantile amnesia. Experiment 1 demonstrated that infant (i.e., postnatal day 17) rats acquire a context-shock association when trained with multiple shocks, as assessed by context freezing one day later. However, they exhibit significant forgetting of this association 10days later. Experiments 2 and 3 showed that even when animals had forgotten the initial learning experience, future conditioning to the same context was NMDAr-independent. There was evidence of a transition to NMDAr-independent context fear learning in animals exposed only to the foot shock in infancy (Experiment 3) or only to the context in infancy (Experiment 3 but not Experiment 2). These latter results suggest that animals do not have to be exposed to the entire conditioning procedure at postnatal day 17 to show a transition to NMDAr-independent context learning. These experiments add to a growing body of evidence that forgotten infant memories can continue to affect later behavior by demonstrating that prior experience alters the mechanisms of future learning.

Developmental rodent models of fear and anxiety: from neurobiology to pharmacology

Anxiety disorders pose one of the biggest threats to mental health in the world, and they predominantly emerge early in life. However, research of anxiety disorders and fear-related memories during development has been largely neglected, and existing treatments have been developed based on adult models of anxiety. The present review describes animal models of anxiety disorders across development and what is currently known of their pharmacology. To summarize, the underlying mechanisms of intrinsic 'unlearned' fear are poorly understood, especially beyond the period of infancy. Models using 'learned' fear reveal that through development, rats exhibit a stress hyporesponsive period before postnatal day 10, where they paradoxically form odour-shock preferences, and then switch to more adult-like conditioned fear responses. Juvenile rats appear to forget these aversive associations more easily, as is observed with the phenomenon of infantile amnesia. Juvenile rats also undergo more robust extinction, until adolescence where they display increased resistance to extinction. Maturation of brain structures, such as the amygdala, prefrontal cortex and hippocampus, along with the different temporal recruitment and involvement of various neurotransmitter systems (including NMDA, GABA, corticosterone and opioids) are responsible for these developmental changes. Taken together, the studies described in this review highlight that there is a period early in development where rats appear to be more robust in overcoming adverse early life experience. We need to understand the fundamental pharmacological processes underlying anxiety early in life in order to take advantage of this period for the treatment of anxiety disorders.

Adults' reports of their earliest memories: consistency in events, ages, and narrative characteristics over time.

Earliest memories have been of interest since the late 1800s, when it was first noted that most adults do not have memories from the first years of life (so-called childhood amnesia). Several characteristics of adults' earliest memories have been investigated, including emotional content, the perspective from which they are recalled, and vividness. The focus of the present research was a feature of early memories heretofore relatively neglected in the literature, namely, their consistency. Adults reported their earliest memories 2-4 times over a 4-year period. Reports of earliest memories were highly consistent in the events identified as the bases for earliest memories, the reported age at the time of the event, and in terms of qualities of the narrative descriptions. These findings imply stability in the boundary that marks the offset of childhood amnesia, as well as in the beginning of a continuous sense of self over time.

Memory's aging echo: Age-related decline in neural reactivation of perceptual details during recollection

Episodic memory decline is a hallmark of normal cognitive aging. Here, we report the first event-related fMRI study to directly investigate age differences in the neural reactivation of qualitatively rich perceptual details during recollection. Younger and older adults studied pictures of complex scenes at different presentation durations along with descriptive verbal labels, and these labels subsequently were used during fMRI scanning to cue picture recollections of varying perceptual detail. As expected from prior behavioral work, the two age groups subjectively rated their recollections as containing similar amounts of perceptual detail, despite objectively measured recollection impairment in older adults. In both age groups, comparisons of retrieval trials that varied in recollected detail revealed robust activity in brain regions previously linked to recollection, including hippocampus and both medial and lateral regions of the prefrontal and posterior parietal cortex. Critically, this analysis also revealed recollection-related activity in visual processing regions that were active in an independent picture-perception task, and these regions showed age-related reductions in activity during recollection that cannot be attributed to age differences in response criteria. These fMRI findings provide new evidence that aging reduces the absolute quantity of perceptual details that are reactivated from memory, and they help to explain why aging reduces the reliability of subjective memory judgments.

Séparation entre perception et conscience : proposition d’un modèle psychologique de l’appareil psychique

PurposesThis paper aims to progressively build a psychological model of the psychic apparatus. MethodThe starting point for our model is a theoretical option validated earlier: the separation between perception and consciousness. By studying the action of an external stimulus inside the psychic apparatus – the conditions, the results and the trajectory of this action – we consider the appropriateness of defining and locating two distinct systems, an unconscious followed by a preconscious in the psychic space consequently appearing between body and consciousness. Finally, once all relationships between the different parts of the model are established, we provide the latter with defence processes, including a repressive process. ResultsThe psychic apparatus is made of two similar blocs, each with its own memory system: at first, the unconscious records the sensory activity of the body and associates an affective value to it; the preconscious then records the figurative activity of the consciousness and replicates the perceptive and affective content of the unconscious in a new type of material that enables remembrance. The unconscious is the dynamic centre of the psychic apparatus and allows communication between body and consciousness. It can animate its own material (the unconscious representations) through perceptive associations and generate processes that have to be recognised as true unconscious thoughts, full of affects and possibly subject to repression. The preconscious has no momentum or affective dimension of its own; it is only the psychic bridge that enables consciousness to receive the associative work of the unconscious. DiscussionBy considering the psychic apparatus in its adaptive function – a system to encounter the world perceptively and react to this experience affectively – we lean towards cognitive psychology, but without losing sight of Freud's theory. Unconscious, preconscious and repression, as we see them, are not exactly Freudian, but are no stranger to metapsychology. Our model stands between cognitive psychology and metapsychology, it does not validate the primacy of consciousness over the unconscious, or that of the unconscious over consciousness. Instead, it considers the entanglement between them: consciousness is in the end an extension of the unconscious and does not function without it. ConclusionEach theoretical proposal along our work attempts to account for many clinical and experimental facts. We hope to bring a different light and new answers to phenomena such as infantile amnesia, dreams, remembrance, and “double consciousness” well known by Binet and his contemporaries.

Hippocampal neurogenesis regulates forgetting during adulthood and infancy.

Throughout life, new neurons are continuously added to the dentate gyrus. As this continuous addition remodels hippocampal circuits, computational models predict that neurogenesis leads to degradation or forgetting of established memories. Consistent with this, increasing neurogenesis after the formation of a memory was sufficient to induce forgetting in adult mice. By contrast, during infancy, when hippocampal neurogenesis levels are high and freshly generated memories tend to be rapidly forgotten (infantile amnesia), decreasing neurogenesis after memory formation mitigated forgetting. In precocial species, including guinea pigs and degus, most granule cells are generated prenatally. Consistent with reduced levels of postnatal hippocampal neurogenesis, infant guinea pigs and degus did not exhibit forgetting. However, increasing neurogenesis after memory formation induced infantile amnesia in these species.

Emotion-based learning: insights from the Iowa Gambling Task

Interest in the cognitive and/or emotional basis of complex decision-making, and the related phenomenon of emotion-based learning, has been heavily influenced by the Iowa Gambling Task. A number of psychological variables have been investigated as potentially important in understanding emotion-based learning. This paper reviews the extent to which humans are explicitly aware of how we make such decisions; the biasing influence of pre-existing emotional labels; and the extent to which emotion-based systems are anatomically and functionally independent of episodic memory. Review of literature suggests that (i) an aspect of conscious awareness does appear to be readily achieved during the IGT, but as a relatively unfocused emotion-based “gut-feeling,” akin to intuition; (ii) Several studies have manipulated the affective pre-loading of IGT tasks, and make it clear that such labeling has a substantial influence on performance, an experimental manipulation similar to the phenomenon of prejudice. (iii) Finally, it appears that complex emotion-based learning can remain intact despite profound amnesia, at least in some neurological patients, a finding with a range of potentially important clinical implications: in the management of dementia; in explaining infantile amnesia; and in understanding of the possible mechanisms of psychotherapy.

Childhood amnesia in the making: Different distributions of autobiographical memories in children and adults.

Within the memory literature, a robust finding is of childhood amnesia: a relative paucity among adults for autobiographical or personal memories from the first 3 to 4 years of life, and from the first 7 years, a smaller number of memories than would be expected based on normal forgetting. Childhood amnesia is observed in spite of strong evidence that during the period eventually obscured by the amnesia, children construct and preserve autobiographical memories. Why early memories seemingly are lost to recollection is an unanswered question. In the present research, we examined the issue by using the cue word technique to chart the distributions of autobiographical memories in samples of children ages 7 to 11 years and samples of young and middle-aged adults. Among adults, the distributions were best fit by the power function, whereas among children, the exponential function provided a better fit to the distributions of memories. The findings suggest that a major source of childhood amnesia is a constant rate of forgetting in childhood, seemingly resulting from failed consolidation, the outcome of which is a smaller pool of memories available for later retrieval.

Your earliest memory may be earlier than you think: Prospective studies of children’s dating of earliest childhood memories.

Theories of childhood amnesia and autobiographical memory development have been based on the assumption that the age estimates of earliest childhood memories are generally accurate, with an average age of 3.5 years among adults. It is also commonly believed that early memories will by default become inaccessible later on and this eventually results in childhood amnesia. These assumptions were examined in 2 prospective studies, in which children recalled and dated their earliest memories at an initial interview and did it again 1 year (Study 1) and 2 years later (Study 2). Systematic telescoping errors emerged: Children substantially postdated their memories for the same events at the follow-up interview, particularly for memories initially dated from earlier ages. These findings have critical methodological and theoretical implications for research on childhood amnesia and autobiographical memory development.

Early memories in young adults from separated and non-separated families

Two studies investigated the earliest memories of New Zealand European young adults (N = 80, Study 1 and N = 120, Study 2) from separated and non-separated families. Participants' earliest memories were assessed for age, for density (how far apart the memories were, Study 2) and for narrative coherence of the memories. Questionnaires were designed to investigate the role of changes in family structure, for example, in the number of adults in the participants' households and the timing of the parental separation. Study 2 further investigated stress and painful divorce-related feelings as additional variables in adjustment after divorce. No overall differences in age of earliest memory emerged between young adults from separated and non-separated parents. Within the group from separated parents, however, memories were earlier when parents separated early in the child's life (<age 7), which related to having extended family ties and more coherent memory narratives from early childhood (Study 2). Participants from separated families reported earlier but sparser memories when they reported higher levels of stress and painful feelings about the separation. The development of early autobiographical memories and the offset of childhood amnesia are discussed via transition and social interaction theories of autobiographical memory.

On the Development of the Autobiographical Self and Autobiographical Memory—Implicit and Explicit Aspects

The autobiographical self and autobiographical memory are developed in a reciprocal process. Both have implicit aspects, inaccessible to consciousness, as well as explicit, conscious aspects. The latter are lost to infantile amnesia by about the fifth year of life, while the implicit aspects are retained. Implicit memory content strongly influences feeling, thinking, and acting, out of our awareness. Only a fraction of overall brain activity is accessible to consciousness. The individual stages of development are described in terms of their genetically programmed maturation steps, as well as their prerequisites in specific, individual, inter-subjective experience. In its particular significance for development, the verbalization of implicit knowledge (“internal-state talk”) in the form of narration will be explained and illustrated. Knowledge of normal development and possible aberrations facilitates, in psychotherapy as a “talking cure,” the alteration of “implicit relational knowledge” strived for through expression in language of the explicit conscious insights made possible by new experience gathered in the analytic relationship.

The onset of childhood amnesia in childhood: A prospective investigation of the course and determinants of forgetting of early-life events

The present research was an examination of the onset of childhood amnesia and how it relates to maternal narrative style, an important determinant of autobiographical memory development. Children and their mothers discussed unique events when the children were 3 years of age. Different subgroups of children were tested for recall of the events at ages 5, 6, 7, 8, and 9 years. At the later session they were interviewed by an experimenter about the events discussed 2 to 6 years previously with their mothers (early-life events). Children aged 5, 6, and 7 remembered 60% or more of the early-life events. In contrast, children aged 8 and 9 years remembered fewer than 40% of the early-life events. Overall maternal narrative style predicted children's contributions to mother–child conversations at age 3 years; it did not have cross-lagged relations to memory for early-life events at ages 5 to 9 years. Maternal deflections of the conversational turn to the child predicted the amount of information children later reported about the early-life events. The findings have implications for our understanding of the onset of childhood amnesia and the achievement of an adult-like distribution of memories in the school years. They highlight the importance of forgetting processes in explanations of the amnesia.

Adults’ earliest memories as a function of age, gender, and education in a large stratified sample.

Childhood amnesia (i.e., a marked paucity of memories from the first 3-4 years of life) has often been examined by asking people for their earliest memory. Such studies have generally been conducted with college students, and thus been unable to examine possible effects of education and current age. We here report the first study on adults' earliest memories based on a large, stratified sample covering the adult life span from age 20 to 70 (n = 1,043). Because of the nature and size of our sample we have been able to investigate a range of factors simultaneously that typically have been studied separately in other studies. Participants with higher education reported earlier first memories than respondents with lower education. Women reported earlier memories than men. There was no interaction between gender and educational level. The current age of the respondents did not affect age of earliest memory, but older respondents had more vivid and more coherent earliest memories relative to younger respondents. Finally, the data provided some support for the claim that elaborative parents have children with earlier memories.

Early experiences and the development of emotional learning systems in rats

Research first reported nearly 50 years ago demonstrated that infant and young animals (including humans) exhibit profoundly faster rates of forgetting (i.e., infantile amnesia) than do adults. In addition to these differences in retention, more recent research has shown that inhibition of fear learning is also very different in infancy than in adulthood. Specifically, extinction of fear early in life is much more resistant to relapse than is extinction later in life. Both of these findings suggest that young animals should be especially resilient to the emergence of mental health disorders, which appears to be at odds with the view that early-life experiences are particularly important for the development of later psychopathologies (such as anxiety disorders) and with the finding that the majority of anxiety disorders first emerge in adolescence or childhood. This apparent paradox might be resolved, however, if exposure to chronic stress early in life affects the maturation of the fear retention and extinction systems, leading to a faster transition to the adult form of each (i.e., long-lasting fear memories and relapse-prone extinction). In several recent studies we have found exactly this pattern; that is, infant rats exposed to maternal-separation stress exhibit adult-like fear and extinction learning early in development. Further, we have demonstrated that some of these effects can be mimicked by exposing the mother to the stress hormone corticosterone in their drinking water (in lieu of the separation procedure). These findings suggest that early-life exposure to stress and stress hormones may act as a general signal that can alter the developmental trajectory of emotional systems and potentially place animals at greater risk for the development of anxiety. The implications of these recent findings for our understanding of the developmental origins of health and disease, and for enhancing preventative and therapeutic treatments across the lifespan, are considered.