Childhood Amnesia – Arizona Forensic Services, LLC

Snap Shot

The question: What can adults, adolescents, and older children remember of the first years of their lives, and how should a court evaluate a reported memory of an event from infancy or very early childhood?

What the research shows: The average adult’s earliest memory dates to about three to three and a half years, and very few reliable memories date from before age two. Infants and toddlers do form memories, and young children can recall early events for a time, but many of those memories are lost during the school years. Reports of memories from before age two are common in large surveys, and researchers disagree about how many are genuine.

What it does not show: The boundary is a gradient that varies across people, cultures, and types of event; it cannot establish that a particular early memory is true or false. Stress and emotion do not appear to exempt events from the first two years from childhood amnesia, but that does not mean memories of later childhood abuse are unreliable.

The law: A witness may testify only from personal knowledge (Fed., Mil., and Ariz. R. Evid. 602). Expert testimony on childhood amnesia is governed by Rule 702 and Houser, and in Arizona by Rule 702, Chapple, Nordstrom, and Salazar-Mercado; under Lindsey, no expert may say whether a particular memory is accurate.

Issues for each side: Prosecutors should anchor early-childhood allegations in the child’s age at the events and at recall and in independent evidence, without presenting a detailed memory of infancy as reliable because it is vivid; defense counsel can present the research on how rarely events from the first two years are retained, without asserting that nothing from early childhood can be remembered.

Most adults can recall little or nothing of their first few years. This gap, called childhood amnesia or infantile amnesia, is among the most consistently replicated findings in memory research. It is not a failure to learn: infants and toddlers acquire language, skills, and knowledge at a rapid rate and show memory for events at the time. What is limited is later access to memories of specific personal experiences from that period.

The phenomenon reaches court when a witness, usually an adult or adolescent, reports remembering something that is alleged to have happened during infancy or the first years of childhood, or when the age at which a child could later recall an event becomes an issue. It arises most often in allegations of childhood abuse, including delayed disclosure and memories recovered after a period of reported amnesia.

This paper addresses adults’ and older children’s recall of early childhood; how memory abilities develop through childhood is treated in the paper on Memory Development. It describes where the boundary falls, how it shifts as children grow, why it occurs, what research shows about reported memories from before age two and about stressful early events, the limits of the evidence, and the federal, military, and Arizona law on personal knowledge and expert testimony.

Where the Boundary Falls

Systematic study of early memories began with a questionnaire study published in the American Journal of Psychology (Miles, 1893), and the basic finding has been reproduced many times since. Across studies, the average age of the earliest memory adults report is about three to three and a half years, and very few reliable memories date from before age two (Bauer, 2015). In a recent large online survey of 6,641 adults, the mean estimated age of the earliest memory was 3.2 years (Akhtar et al., 2018).

The boundary depends on how memory is defined. When undergraduates and older adults sorted childhood events into those they recollected and those they only knew had happened, the transition from mostly known to mostly recollected memories fell at about 4.7 years (Multhaup et al., 2005). The boundary also depends on the event. In a study of 222 college students asked about datable family events, some participants recalled a hospitalization or the birth of a sibling that occurred when they were two, while recall of a family death or move began at about three; mothers judged most of these memories accurate, and the researchers’ measure of outside sources such as family stories was negatively related to recall from the earliest ages, although that measure cannot rule out such sources for any individual memory (Usher & Neisser, 1993).

Culture and gender matter as well. In New Zealand studies, adults of Māori background, whose culture places strong emphasis on the past, reported earlier first memories than New Zealand European adults, who in turn reported earlier memories than Asian adults, a difference driven by the late memories of Asian women; women in all three groups gave fuller accounts than men (MacDonald et al., 2000). The age of the rememberer matters too. In a recent comparison, older adults dated their earliest memories to a later age than young adults did and rated them as more vivid, emotionally intense, and meaningful (Ece & Gülgöz, 2026). No single age marks the boundary for everyone.

The Boundary Moves During Childhood

Childhood amnesia is not fixed at birth or at age three. Using a timeline procedure that compared children, adolescents, and adults, researchers found that children and adolescents reported a larger share of memories from before age three than adults did, and that their earliest memories were younger than the traditional three-and-a-half-year boundary, while adults’ were not (Tustin & Hayne, 2010). Early memories are therefore available for a time and then lost.

Prospective studies show when that loss occurs. Children who discussed unique events with their mothers at age three were later interviewed about those events; children tested at five, six, and seven remembered 60% or more of the events, while children tested at eight and nine remembered fewer than 40% (Bauer & Larkina, 2014). In a study that asked 37 children for their earliest memories three times over eight years, the earliest memory reported changed from interview to interview, the youngest children forgot more than half of their initially reported memories, and of the information the youngest group provided, less than 10% was the same after eight years and 22% was contradictory; for children who had been six to nine years old at the first interview, 25% to 32% of the information remained the same (Peterson et al., 2018). Emotion and coherent context predicted retention.

These findings bear on accounts given at different ages. A young child’s report of an event from age two or three is a different kind of evidence from an adult’s report of the same event, because the young child’s memory has not yet passed through the period in which many early memories are lost. The later boundary associated with puberty, and the overrepresentation of memories from adolescence and early adulthood, is discussed in the paper on Memory Across Puberty and the Reminiscence Bump.

Why Childhood Amnesia Occurs

Freud attributed the gap to the repression of early experience, but developmental research has not supported that account; it points instead to the gradual maturation of the processes that encode, consolidate, store, and retrieve memories, together with cognitive and social developments that organize memories into a personal past (Howe & Courage, 1993; Bauer, 2015). Bauer (2015) described childhood amnesia as the product of two complementary processes: memories formed early are more vulnerable to forgetting because the neural and cognitive systems that consolidate them are immature, while the abilities that make memories durable and retrievable, such as language, a sense of self, and an understanding of time and place, develop gradually through the preschool and school years.

Several of those abilities have been studied directly. The emergence of a cognitive sense of self late in the second year provides a framework in which experiences can be stored as having happened to oneself (Howe & Courage, 1997). Language shapes what can later be told: in a study of children assessed six months to a year after a novel event, the children had acquired the words needed to describe it, yet none verbally reported any aspect of the event that had not been part of his or her vocabulary when it occurred (Simcock & Hayne, 2002). Encoding, retention, and retrieval all improve gradually across infancy, so early memories are formed under conditions that make later retrieval difficult (Hayne, 2004).

Neuroscience has added two lines of evidence, one from animals and one from human infants. In mice, high rates of new neuron formation in the infant hippocampus were associated with rapid forgetting, and reducing neurogenesis after learning reduced that forgetting; in guinea pigs and degus, species in which most of these neurons form before birth, infants did not show the same forgetting unless neurogenesis was increased (Akers et al., 2014). These are animal findings and suggest a mechanism rather than establish one in humans. In human infants, a functional MRI study found that hippocampal activity while viewing new photographs predicted later memory-based looking from about one year of age, indicating that the capacity to encode individual memories is present in infancy; the authors concluded that childhood amnesia may depend more on what happens to memories after encoding, including whether they can later be retrieved, than on a failure to form them (Yates et al., 2025).

Reported Memories From Before Age Two

Many people nonetheless report memories from infancy. In the survey of 6,641 adults described above, nearly 40% dated their first memory to age two or younger, and 893 respondents dated it to age one or younger (Akhtar et al., 2018). The authors characterized many such memories as improbable and likely fictional, suggesting that they may be constructed from fragments, photographs, family stories, and knowledge about one’s early life, and then experienced as remembered. The figures above are those of the original article; the journal later published a corrigendum to it (“Corrigendum: Fictional First Memories,” 2020), which anyone relying on the specific numbers should consult. A group of developmental researchers published a comment arguing against characterizing these memories as fiction (Bauer et al., 2019), and the original authors replied (Akhtar et al., 2019).

The disagreement concerns how many reported very early memories are genuine. Adults generally estimate the age at which a remembered event occurred, and those estimates can be wrong in either direction. A memory of infancy reported sincerely and with confidence is not evidence of lying; it may reflect reconstruction from other sources, a misdated later event, or, in some cases, a genuine early memory. Research cannot distinguish among these possibilities for a particular report without independent information about the event and the person’s exposure to accounts of it.

Stressful and Traumatic Early Events

A common intuition is that frightening or painful events are exceptions to childhood amnesia. Studies of medical events, which allow researchers to verify what happened, do not support that intuition for the earliest years. Children who were seen in an emergency room for injuries at one or two years of age were interviewed five years later; most of those who had been one year old recalled nothing about the event, while most who had been two recalled a great deal, and the former one-year-olds who did recall the event often blended in details from other, related experiences (Peterson & Parsons, 2005). In a study of children questioned years after a stressful and painful medical procedure undergone between ages two and six, children who had been four or older at the procedure were more accurate than those who had been younger than four, and longer delays reduced the amount of correct information without increasing errors (Quas et al., 1999).

These studies concern verified, single events, and they show both sides of the question. Events from the first two years, even highly stressful ones, are rarely retained in a form a child can later describe, and when they are, accuracy is a concern. Stressful events experienced from about age two or three onward, by contrast, can be remembered for years, often accurately in their central content (Peterson, 2012). The research does not establish whether chronic early maltreatment shifts the boundary of childhood amnesia earlier or later, and claims in either direction should be treated as unresolved. Questions about memories said to have been recovered after a period of amnesia are addressed in the paper on Recovered and Repressed Memory.

Limits of the Evidence

Most research on adults’ earliest memories relies on self-reports whose dating cannot be checked, so the boundary of childhood amnesia is itself estimated from memories of uncertain age and origin. Studies that can verify early events, such as those involving medical procedures or events discussed with parents, are smaller and concern particular kinds of experience. Samples are largely from Western, educated populations, and cultural differences show that the averages do not transfer unchanged across groups. The animal research on neurogenesis concerns rodents and other species, and the infant imaging research measures encoding in a laboratory task, not the later fate of autobiographical memories.

The findings describe probabilities across groups. They indicate that memories from before about age two are rarely reliable and that memories from the third and fourth years are possible but fragile and often lost. They cannot establish that a particular person did or did not retain a particular early memory, and they say little about events from later childhood, which are well within the range in which memories can be durable.

Questions to Ask About This Research

When the average earliest memory of about three to three and a half years is cited to argue that a witness cannot remember an event from age three, counsel should ask whether the conclusion follows for this person, because the average conceals variation by culture, gender, type of event, and the age of the rememberer (MacDonald et al., 2000; Tustin & Hayne, 2010; Usher & Neisser, 1993). When Akhtar et al. (2018) is offered to show that memories from before age two are fictional, counsel should ask what exactly was counted: the study measured self-reported first memories and estimated ages in an online survey, did not verify the events, and drew a published comment disputing the “fictional” characterization (Bauer et al., 2019). When Peterson and Parsons (2005) or Quas et al. (1999) is cited about stressful events, counsel should ask who was studied and whether a medical event resembles the event at issue in its repetition, meaning, and later discussion. When the neurogenesis findings of Akers et al. (2014) are used to explain why a person cannot remember, counsel should ask whether studies of mice, guinea pigs, and degus can support a conclusion about one human witness. These questions are explained in “Reading Research Claims: A Guide for Attorneys” on this site.

Childhood Amnesia and the Law

Federal and Military Standards

A witness may testify to a matter only if evidence is introduced sufficient to support a finding that the witness has personal knowledge of it, and the witness’s own testimony may supply that evidence (Fed. R. Evid. 602; Mil. R. Evid. 602). A claim to remember an event from infancy ordinarily satisfies that threshold, and doubts about whether the memory is genuine usually go to weight, to be tested through cross-examination, corroborating or contradicting evidence, and, where admissible, expert testimony. Expert testimony on childhood amnesia is governed by Federal Rule of Evidence 702, as amended December 1, 2023, which requires the proponent to show that it is more likely than not that the testimony rests on sufficient facts or data, reflects reliable principles and methods, and reflects a reliable application of them to the case. Daubert v. Merrell Dow Pharmaceuticals, Inc. (1993) makes the trial judge a gatekeeper, and Kumho Tire Co. v. Carmichael (1999) extends that obligation to all expert testimony, including non-scientific technical or other specialized knowledge. In courts-martial, Military Rule of Evidence 702 tracks the federal rule; the 2023 amendment took effect in the military rule in 2025 through Military Rule of Evidence 1102 (Joint Service Committee on Military Justice, 2025; practitioners should confirm current text), and United States v. Houser (1993) sets out six admissibility factors, including the expert’s qualifications, the relevance and reliability of the testimony, and its probative value.

The research is well established at the general level, and testimony that describes the boundary, its variability, and the findings on very early memories is the kind of general education Rule 702 contemplates. Testimony that applies the research to conclude that a particular witness’s memory is false, or genuine, goes beyond what the research can support and invades the factfinder’s role in judging credibility.

Arizona

Arizona Rule of Evidence 602 contains the same personal-knowledge requirement. Arizona Rule of Evidence 702 adopted the Daubert standard effective January 1, 2012, and was amended effective January 1, 2024, to track the 2023 federal amendment (Ariz. Sup. Ct. Order R-23-0004). State v. Chapple (1983) is Arizona’s leading case on eyewitness expert testimony: the Arizona Supreme Court held that excluding eyewitness memory testimony was an abuse of discretion on the facts of that case, and State v. Nordstrom (2001) confirmed that admission otherwise remains within the trial court’s discretion. Under State v. Salazar-Mercado (2014), an expert may provide general, educational testimony about childhood amnesia without applying it to the facts, if the testimony satisfies Rule 702 and Rule 403. Under State v. Lindsey (1986) and State v. Moran (1986), no expert may opine, directly or indirectly, on whether a particular witness is truthful or whether a particular memory is accurate; those limits apply to testimony offered by either side.

Special Issues in Legal Practice

The principles described above apply with equal force to every party in a legal proceeding. The science operates the same way regardless of who is asking the questions, and the research summarized here does not by itself favor either side. What differs between the parties is not the science but the vantage point — the particular places where these issues tend to surface, and the particular errors each party is best positioned to guard against. The two summaries below identify those recurring issues. They are offered for orientation, not as litigation strategy; in every case the controlling question is what the evidence in that case will, and will not, support, and the expert’s role is to inform the trier of fact rather than to advocate for either side.

Special Issues for Prosecutors

The research supports several propositions prosecutors can legitimately present. Childhood amnesia is a gradient, not a bright line; memories of events from about age three onward can be genuine, and stressful events from the preschool years can be remembered for years, often accurately in their central content. Children recall early events more fully soon after they occur than they will as adults, so a young child’s report of a recent event is not undermined by research on adults’ earliest memories. Many allegations of childhood abuse concern events from later childhood, and for those the research on childhood amnesia has little direct bearing. Prosecutors are well positioned to document the child’s age at the alleged events and at each disclosure, to preserve early statements, and to develop evidence independent of memory.

The research also counsels caution. A detailed, confident memory attributed to the first two years of life is unlikely to be a reliable recollection of that period, however sincerely it is held, and presenting its vividness or emotion as evidence of accuracy overstates the research. Memories from the third and fourth years are fragile, often forgotten during the school years, and can incorporate details from other events or from family accounts. Where an early memory emerged long after the event, the circumstances of its emergence warrant the attention discussed in the paper on Recovered and Repressed Memory.

Special Issues for Defense

The research supports several propositions defense counsel can legitimately present. Adults generally retain few memories from before about three to three and a half years, and very few reliable memories from before age two. Early memories that do exist are often lost during the school years and can change in content when they survive, and reports of very early memories are common in large surveys even though many are unlikely to be accurate. Stressful events from the first two years are rarely retained in a form that can later be described. Expert testimony explaining these findings, together with evidence of the witness’s age at the event and of family stories, photographs, or other sources to which the witness was exposed, can help the factfinder evaluate a claimed early memory.

The research also counsels caution about the limits that apply to the defense. The boundary varies across people, cultures, and events, and memories from about age two or three onward can be genuine. A young child’s account of a recent early event is not governed by research on adults’ memories. The research cannot establish that a particular memory is false, and arguments that extend childhood amnesia to events from later childhood, or that treat a reported memory of early childhood as evidence of fabrication, go beyond the evidence.

This paper is for educational purposes only and is not legal advice. The author is a psychologist, not an attorney; summaries of law are general and must be verified against current authority or with a licensed attorney.

References

Akers, K. G., Martinez-Canabal, A., Restivo, L., Yiu, A. P., De Cristofaro, A., Hsiang, H.-L., Wheeler, A. L., Guskjolen, A., Niibori, Y., Shoji, H., Ohira, K., Richards, B. A., Miyakawa, T., Josselyn, S. A., & Frankland, P. W. (2014). Hippocampal neurogenesis regulates forgetting during adulthood and infancy. Science, 344(6184), 598–602. https://doi.org/10.1126/science.1248903

Akhtar, S., Justice, L. V., Morrison, C. M., & Conway, M. A. (2018). Fictional first memories. Psychological Science, 29(10), 1612–1619. https://doi.org/10.1177/0956797618778831

Akhtar, S., Justice, L. V., Morrison, C. M., Conway, M. A., & Howe, M. L. (2019). What are autobiographical memories? A reply to Bauer, Baker-Ward, Krøjgaard, Peterson, and Wang (2019). Psychological Science, 30(9), 1400–1402. https://doi.org/10.1177/0956797619868994

Bauer, P. J. (2015). A complementary processes account of the development of childhood amnesia and a personal past. Psychological Review, 122(2), 204–231. https://doi.org/10.1037/a0038939

Bauer, P. J., Baker-Ward, L., Krøjgaard, P., Peterson, C., & Wang, Q. (2019). Evidence against depiction as fiction: A comment on “Fictional first memories” (Akhtar, Justice, Morrison, & Conway, 2018). Psychological Science, 30(9), 1397–1399. https://doi.org/10.1177/0956797619834510

Bauer, P. J., & Larkina, M. (2014). The onset of childhood amnesia in childhood: A prospective investigation of the course and determinants of forgetting of early-life events. Memory, 22(8), 907–924. https://doi.org/10.1080/09658211.2013.854806

Corrigendum: Fictional first memories. (2020). Psychological Science, 31(9), 1205–1207. https://doi.org/10.1177/0956797620950665

Ece, B., & Gülgöz, S. (2026). Age-related differences and commonalities in remembering earliest memories: A comparison of young and older adults. Memory, 34(1), 57–69. https://doi.org/10.1080/09658211.2025.2594556

Hayne, H. (2004). Infant memory development: Implications for childhood amnesia. Developmental Review, 24(1), 33–73. https://doi.org/10.1016/j.dr.2003.09.007

Howe, M. L., & Courage, M. L. (1993). On resolving the enigma of infantile amnesia. Psychological Bulletin, 113(2), 305–326. https://doi.org/10.1037/0033-2909.113.2.305

Howe, M. L., & Courage, M. L. (1997). The emergence and early development of autobiographical memory. Psychological Review, 104(3), 499–523. https://doi.org/10.1037/0033-295X.104.3.499

Joint Service Committee on Military Justice. (2025). Amendments to the Military Rules of Evidence since 1984 (G. E. Maggs, Ed.; 2025 ed.). https://jsc.defense.gov/Portals/99/MRE%20Amendments%202025.pdf

MacDonald, S., Uesiliana, K., & Hayne, H. (2000). Cross-cultural and gender differences in childhood amnesia. Memory, 8(6), 365–376. https://doi.org/10.1080/09658210050156822

Miles, C. (1893). A study of individual psychology. The American Journal of Psychology, 6(4), 534–558. https://doi.org/10.2307/1411191

Multhaup, K. S., Johnson, M. D., & Tetirick, J. C. (2005). The wane of childhood amnesia for autobiographical and public event memories. Memory, 13(2), 161–173. https://doi.org/10.1080/09608210344000652

Peterson, C. (2012). Children’s autobiographical memories across the years: Forensic implications of childhood amnesia and eyewitness memory for stressful events. Developmental Review, 32(3), 287–306. https://doi.org/10.1016/j.dr.2012.06.002

Peterson, C., Hallett, D., & Compton-Gillingham, C. (2018). Childhood amnesia in children: A prospective study across eight years. Child Development, 89(6), e520–e534. https://doi.org/10.1111/cdev.12972

Peterson, C., & Parsons, B. (2005). Interviewing former 1- and 2-year olds about medical emergencies 5 years later. Law and Human Behavior, 29(6), 743–754. https://doi.org/10.1007/s10979-005-8378-0

Quas, J. A., Goodman, G. S., Bidrose, S., Pipe, M.-E., Craw, S., & Ablin, D. S. (1999). Emotion and memory: Children’s long-term remembering, forgetting, and suggestibility. Journal of Experimental Child Psychology, 72(4), 235–270. https://doi.org/10.1006/jecp.1999.2491

Simcock, G., & Hayne, H. (2002). Breaking the barrier? Children fail to translate their preverbal memories into language. Psychological Science, 13(3), 225–231. https://doi.org/10.1111/1467-9280.00442

Tustin, K., & Hayne, H. (2010). Defining the boundary: Age-related changes in childhood amnesia. Developmental Psychology, 46(5), 1049–1061. https://doi.org/10.1037/a0020105

Usher, J. A., & Neisser, U. (1993). Childhood amnesia and the beginnings of memory for four early life events. Journal of Experimental Psychology: General, 122(2), 155–165. https://doi.org/10.1037/0096-3445.122.2.155

Yates, T. S., Fel, J., Choi, D., Trach, J. E., Behm, L., Ellis, C. T., & Turk-Browne, N. B. (2025). Hippocampal encoding of memories in human infants. Science, 387(6740), 1316–1320. https://doi.org/10.1126/science.adt7570

Legal Authorities

Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993).

Kumho Tire Co. v. Carmichael, 526 U.S. 137 (1999).

State v. Chapple, 135 Ariz. 281, 660 P.2d 1208 (1983).

State v. Lindsey, 149 Ariz. 472, 720 P.2d 73 (1986).

State v. Moran, 151 Ariz. 378, 728 P.2d 248 (1986).

State v. Nordstrom, 200 Ariz. 229, 25 P.3d 717 (2001).

State v. Salazar-Mercado, 234 Ariz. 590, 325 P.3d 996 (2014).

United States v. Houser, 36 M.J. 392 (C.M.A. 1993).

Fed. R. Evid. 602.

Fed. R. Evid. 702.

Ariz. R. Evid. 602.

Ariz. R. Evid. 702.

Ariz. Sup. Ct. Order R-23-0004 (amending Ariz. R. Evid. 702, effective Jan. 1, 2024).

Mil. R. Evid. 602.

Mil. R. Evid. 702.

Mil. R. Evid. 1102.

Related topics from Arizona Forensic Services: Child Abuse Allegations