Science Briefs

Oh Where, Oh Where Have Those Early Memories Gone? A Developmental Perspective on Childhood Amnesia

Whereas memories of many past experiences seemingly come and go, there is a period of life from which adults reliably fail to recall much if anything at all.

By Patricia J. Bauer, PhD

"The horror of that moment," the King went on, "I shall never, never forget!"
"You will, though," the Queen said, "if you don't make a memorandum of it."

(Lewis Carroll, Through the Looking Glass and What Alice Found There, 1872, emphasis in original)

In his brief dialogue between the King and the Queen-two of the chess-piece sovereigns of Looking-glass House-Lewis Carroll captured the complementary sides of the memory coin. The King, having experienced a "horrifying" event (being set upon a table by Alice, a relative giant whom the King could neither see nor hear) expresses absolute faith in remembering. The Queen, on the other hand, is less optimistic, suggesting that without some intervention (a memorandum) forgetting will ensue. In a rare instance, the reality experienced by the King and Queen on their side of the looking glass is reflected on the drawing-room side as well. Memory is at times seemingly indelible and at other times frustratingly fallible. What is more, in true looking glass fashion, the same past experience can at one moment impinge upon consciousness unbidden and at another, elude deliberate attempts to recollect it.

Whereas memories of many past experiences seemingly come and go, there is a period of life from which adults reliably fail to recall much if anything at all. Well over 100 years ago, Miles (1893) published the first account in a psychological journal of the phenomenon that would come to be known as infantile amnesia or childhood amnesia: the relative paucity among adults of verbally accessible memories from the first 3-4 years of life. The phenomenon was subsequently amended with the observation that from the ages of 3 to 7 years, adults have fewer memories than would be expected, based on forgetting alone (e.g., Pillemer & White, 1989; Wetzler & Sweeney, 1986). The observation is one of the most replicable in the literature: Whether tested in 1893 or 1999 (West & Bauer, 1999), among adults in Western cultures, the average age of earliest memory is age 3 to 3½ years.

A number of theories as to the source of childhood amnesia have been advanced. Perhaps most infamously, Freud (1916/1966) attributed "the remarkable amnesia of childhood" to repression of inappropriate or disturbing content of early, often traumatic (due to their sexual nature) experiences. Most other theories fall into one of two categories: adults lack memories from early in life because no memories were formed or memories were formed, but later became inaccessible as a result of cognitive changes, for example (e.g., the onset of language). Strikingly, until the middle of the 1980s, explanations as to the source of childhood amnesia were advanced without reference to data from a seemingly critical study population-children! Conclusions about memory in children were drawn nonetheless. An illustrative (though by no means isolated) example is Kihlstrom and Harackiewicz's (1982) observation that "…despite the wealth of experiences which young children have, their autobiographical records are typically quite fragmentary before age seven, and the earliest memory is rarely dated before age three" (p. 134). This characterization was offered in an article in which none of the 37 references was to research with human children (though some research on the ontogeny of memory in nonhuman animals was cited).

The reasons for the lack of attention to children's memories were both theoretical and empirical. The dominant model-Piagetian theory-suggested that it was not until children were of school age that they formed coherent memories of past events. The perspective seemed to be born out empirically. When children were tested with standard laboratory materials (e.g., lists of unrelated words), they performed poorly. They appeared to become reasonably skilled mnemonists at just about the same time as adults begin to have reliable autobiographical records, namely, age 7 years. However, the ground breaking work of researchers such as Jean Mandler and Katherine Nelson made clear that such tasks grossly underestimated children's mnemonic competence. When preschoolers were tested with materials that were inherently structured and meaningful-such as well formed stories (e.g., Mandler & Johnson, 1977) and familiar, "scripted" events (e.g., what happens at a fast food restaurant: e.g., Nelson, 1978)-their memories were well organized and accurate, albeit not as detailed as those of older children and adults.

Observations of preschoolers' abilities to recall stories and report on scripted events opened the door for inquiries into their abilities to recall the stuff of which autobiographical memories are made, namely, unique events from the personal past. Beginning in the middle 1980s, several research laboratories walked through the door. Robyn Fivush and her colleagues (Fivush, Gray, & Fromhoff, 1987) published one of the first reports of autobiographical recall by children only 2½ years of age. The children provided verbal descriptions of unique events experienced 6 or more months in the past. Several other reports followed, each indicating that within the period eventually obscured by childhood amnesia, children had remarkably rich autobiographies (for reviews, see Bauer, in press-b; Nelson & Fivush, 2004).

Not only were preschoolers found to remember but, using imitation-based tasks, researchers revealed mnemonic competence in children even before they could talk (Bauer, 2004). In imitation-based tasks, children watch an adult use props to produce an action or sequence of actions that children then are invited to imitate. There are numerous reasons to believe that the technique provides a nonverbal analogue to explicit memory tasks such as verbal report, including findings of impairments in imitation by individuals with both adulthood- and childhood-onset medial temporal lobe amnesia (McDonough, Mandler, McKee, & Squire, 1995, and Adlam, Vargha-Khadem, Mishkin, & de Haan, in press, respectively; see Bauer, 2005, for elaboration of the argument). Infants remember the actions of sequences, the objects used to produce them, and the order in which the actions unfold, and thus reveal episodic precursors of autobiographical memory. Moreover, at least by the middle of the second year, the memories are retrievable after weeks and even months and thus are relatively enduring.

If preschoolers and even infants remember unique events over long periods of time, why then as adults are we unable to recall early childhood? The answer likely lies in the complement of remembering, namely, forgetting. Forgetting is in fact a critical component of the definition of childhood amnesia: a smaller number of memories from before the age of 7 years than would be expected based on forgetting alone. Indeed, it is the apparently "off the charts" rate of forgetting that makes the phenomenon so mysterious. But what, precisely, is the "expected" rate of forgetting? In a research area in which theories about function in childhood were advanced in the absence of data from children, it is perhaps not surprising to learn that the "expected" rate of forgetting is derived solely from work with adults. For example, in their oft-cited demonstration of the phenomenon of childhood amnesia, Wetzler and Sweeney (1986) applied to adult data (from Rubin, 1982) a forgetting function based on memories from age 8 until adulthood. They then applied the function to data from birth to age 6 years. The good fit of the function to the later data and its poor fit to the early data provided the evidence of accelerated forgetting of events from the early childhood years (see also Crovitz & Schiffman, 1974; Rubin, Wetzler, & Nebes, 1986).

Application of the adult standard to data from early childhood was considered acceptable because of a widely held assumption that the rate of forgetting is a constant across the lifespan (e.g., Rubin & Wenzel, 1996). Yet as evidence of young children's mnemonic prowess has grown, so too have reasons to expect developmental differences in the rate of forgetting, especially in the period eventually obscured by childhood amnesia. Although from a relatively young age, children retain memories over long periods of time, younger children nevertheless exhibit faster rates of forgetting, relative to older children (e.g., Bauer, 2004; in press-a). Differential rates of forgetting are apparent in infancy and very early childhood as well as in the preschool years. They likely are linked to neuro-developmental changes that make memories formed in early childhood more vulnerable to consolidation and storage failures, relative to memories formed later in life (see Bauer, 2004, for a review).

From the standpoint of theories as to the source of childhood amnesia, the implications of age-related differential rates of forgetting could be profound. It is entirely likely that were we to fit data based on early-childhood rates of forgetting, rather than adult rates, we would find that the observation of "…accelerated forgetting over and above normal forgetting…" (Wetzler & Sweeney, 1986, p. 194), would disappear, and the number of memories from early in life would be exactly as expected. Unfortunately, at this time, this possibility cannot be put to empirical test because we lack systematic studies of children of different ages, tested after long retention intervals, for memories of personally significant events. I expect that if we had them, we would see that within the period of childhood, memories formed at age 8 years and older would be forgotten at a slower rate, relative to memories formed at the ages of 4 and 6 years, for example. Until such data are available, all we know is that the forgetting function that fits retrospective data collected from adults for life events from age 8 years onward does not fit the data from age 6 years and younger.

The question of "Oh where, oh where have those early memories gone?" has occupied autobiographical memory researchers for well over a century. Most of the speculation has been from a decidedly non-developmental perspective. When the distribution of events remembered and events apparently forgotten is examined through adult lenses, it appears that an explanation for accelerated forgetting of events from the early years is required. However, when we look forward through developmental lenses, what we see is that with increasing age, rates of remembering and forgetting begin to approximate those in adulthood. What this perspective lacks in glamour and mystery, it makes up for by permitting us to see the continuity of autobiographical memory that may otherwise be obscured. Continuity is itself a precious commodity. In the words of D. Ewen Cameron (1963):

Intelligence may be the pride-the towering distinction of man; emotion gives colour and force to his actions; but memory is the bastion of his being. Without memory, there is no personal identity, there is no continuity to the days of his life. Memory provides the raw material for designs both small and great. Thus, governed and enriched by memory, all the enterprises of man go forward (p. 325).

References
Adlam, A.-L. R.., Vargha-Khadem, F., Mishkin, M., & de Haan, M. (in press). Deferred imitation of action sequences in developmental amnesia. Journal of Cognitive Neuroscience.

Bauer, P. J. (in press-a). Developments in declarative memory: Decreasing susceptibility to storage failure over the second year of life. Psychological Science.

Bauer, P. J. (in press-b). Remembering the times of our lives: Memory in infancy and beyond. Mahwah, NJ: Lawrence Erlbaum Associates.

Bauer, P. J. (2004). Getting explicit memory off the ground: Steps toward construction of a neuro-developmental account of changes in the first two years of life. Developmental Review, 24, 347-373.

Bauer, P. J. (2005). New developments in the study of infant memory. In D. M. Teti (Ed.), Blackwell Handbook of Research Methods in Developmental Science (pp. 467-488). Oxford, United Kingdom: Blackwell Publishing.

Cameron, D. E. (1963). The processes of remembering. British Journal of Psychiatry, 109, 325- 340.

Carroll, Lewis (1872/1982). Through the Looking Glass and What Alice Found There (p. 94 of The Complete Illustrated Works of Lewis Carroll, New York: Crown Publishers Inc, 1982).

Crovitz, H. F., & Schiffman, H. (1974). Frequency of episodic memories as a function of their age. Bulletin of the Psychonomic Society, 4, 517-518.

Fivush, R., Gray, J. T., Fromhoff, F. A. (1987). Two-year-olds talk about the past. Cognitive Development, 2, 393-409.

Freud, S. (1916/1966). The archiac features and infantilism of dreams. In Introductory lectures on psychoanalysis. Translated and edited by J. Strachey. New York: Norton.

Kihlstrom, J. F., & Harackiewicz, J. M. (1982). The earliest recollection: A new survey. Journal of Personality, 50, 134-148.

Mandler, J. M., & Johnson, N. S. (1977). Remembrance of things parsed: Story structure and recall. Cognitive Psychology, 9, 111-151.

McDonough, L., Mandler, J. M., McKee, R. D., & Squire, L. R. (1995). The deferred imitation task as a nonverbal measure of declarative memory. Proceedings of the National Academy of Sciences, 92, 7580-7584.

Miles, C. (1893). A study of individual psychology. American Journal of Psychology, 6, 534- 558.

Nelson, K. (1978). How young children represent knowledge of their world in and out of language. In R. S. Siegler (Ed.), Children's thinking: What develops? (pp. 255-273). Hillsdale, NJ: Erlbaum.

Nelson, K., & Fivush, R. (2004). The emergence of autobiographical memory: A social cultural developmental theory. Psychological Review, 111, 486-511.

Pillemer, D. B., & White, S. H. (1989). Childhood events recalled by children and adults. In H. W. Reese (Ed.), Advances in child development and behavior, Volume 21 (pp. 297-340). Orlando, FL: Academic Press.

Rubin, D. C. (1982). On the retention function for autobiographical memory. Journal of Verbal Learning and Verbal Behavior, 21, 21-38.

Rubin, D. C., & Wenzel, A. E. (1996). One hundred years of forgetting: A quantitative description of retention. Psychological Review, 103, 734-760.

Rubin, D. C., Wetzler, S. E., & Nebes, R. D. (1986). Autobiographical memory across the adult lifespan. In D. C. Rubin (Ed.), Autobiographical memory (pp. 202-221). Cambridge: Cambridge University Press.

West, T. A., & Bauer, P. J. (1999). Assumptions of infantile amnesia: Are there differences between early and later memories? Memory, 7, 257-278.

Wetzler, S. E., & Sweeney, J. A. (1986). Childhood amnesia: An empirical demonstration. In D. C. Rubin (Ed.), Autobiographical memory (pp. 191-201). New York: Cambridge University Press.

About the Author
Patricia J. Bauer earned her PhD in Experimental Developmental Psychology from Miami University in 1985. She was a postdoctoral fellow at the University of California, San Deigo (1985-1989), and then joined the faculty of the Institute of Child Development, University of Minnesota (since 1989), where she is currently the Rodney S. Wallace Professor for the Advancement of Teaching and Learning. As of July, 2005, she will be joining the facult of the Department of Psychological and Brain Sciences at Duke University. Her research program is in developmental cognitive science, with particular emphasis on memory. She is especially concerned with development in infancy and early childhood, and with relations between functional changes and neuro-developmental changes. Beyond early childhood, she focuses on the questions of how changes in basic mnemonic processes, and how the socio-cultural environment in which development takes place, contribute to age-related changes and to individual variability in autobiographical or personal memory. She has published over 90 articles and chapters and is author of the forthcoming volume Remembering the times of our lives: Memory in infancy and beyond (Erlbaum). Professor Bauer is the 1993 recipient of the APA Distinguished Scientific Award for Early Career Contribution to Psychology in the Developmental Area, has an Independent Scientist Award from the National Institutes of Health, is Editor of the Journal of Cognition and Development, and is past president of the Cognitive Development Society.