Childhood Amnesia Essay, Research Paper

Childhood Amnesia

A fundamental aspect of human memory is that the more time elapsed since an event, the fainter the memory becomes. This has been shown to be true on a relatively linear scale with the exception of our first three to four years of life (Fitzgerald, 1991). It is even common for adults not to have any memory before the age of six or seven. The absence of memory in these first years has sparked much interest as to how and why it happens. Ever since Freud (1916/1963) first popularized the phenomenon there have been many questions and few robust empirical studies. Childhood amnesia is defined as the period of life from which no events are remembered (Usher & Neisser, 1993) beginning at birth and ending at the onset of your first memories. The implications of why this occurs are important for the understanding of how our memory system develops and the memory formation process.

Research Limitations:

There have been many hypothesized causes for childhood amnesia but very little strong evidence to support them. This problem arises out of the difficulty of obtaining reliable information pertaining to this area of study. Research is only as good as the information used. Most studies have used adult participants who are asked to report their earliest memories and the date. There are several factors contributing to the unreliability of this data. In a self-report method, people often have difficulty pinpointing what their earliest memory is and even more difficulty getting an accurate date. Verification of the memories is also a problem since it is nearly impossible to design and conduct a study that observes the initial experience to compare with the subsequent recall. The experience reported by a participant can often be checked with another family member but their memories are also prone to errors.

In this field there are also many other confounding variables that experimenters must try minimize. One such variable is the family specific knowledge that a volunteer has accumulated over the course of their life. Loftus, (1993) suggested that early childhood memories are greatly influenced by one’s amassed, family knowledge. For example, a participant who knows that his or her cousin was closely involved in their upbringing is likely to guess that he or she was present at an important event without any actual memory of the fact. Contributing factors to this are family stories, photographs, home movies, etc.

The variance of memories between participants also makes it hard to convert what is reported into significant terms. For example, my earliest memory is from when I was about four years old and my grandmother gave me a piece of amethyst in a wooden quart basket similar to one you buy berries in. This information given its degree of accuracy is quite difficult to generalize since every other person will recount a unique story. A method used by experimenters to compensate for this is the targeting of a specific, datable event common to many individuals. In the 1993 experiment by Usher and Neisser, these ‘target events’ consisted of the birth of a younger sibling, a hospitalization, the death of a family member and a family move. The use of targeted recall has helped solve one problem with infantile amnesic research but as we will see there are still many problems with the experimental evidence that has been gathered.

Experimental Evidence:

Usher and Neisser conducted one of the most influential studies in the field of childhood amnesia in 1993. The purpose of this experiment was to improve on the self-report studies done in the past and to examine the relationship between the nature of the events and the age at which they can be remembered. They used a specific questioning method in a between-groups study of adults’ memories relating to each of the four aforementioned ‘target’ events. They found that the earliest age that these events could be recalled was two for the sibling birth and hospitalization and three for the death and move. They also found no sex differences for the data as proposed by some earlier experiments (Dudycha & Dudycha, 1941). The memories were verified by the participants’ mothers and judged as mostly accurate. These results suggest that the earliest memory recalled in adulthood will vary depending on the significance and or understanding of the event. The birth of a sibling is especially relevant for a young child because of all the discussion and anticipation preceding the birth. This event usually includes many changes in the everyday life for the child and is therefore more likely to be remembered. In comparison, a death is not well understood by a young child and usually will not be as easy to remember. The high levels of emotion (and pain) are said to account for the preservation of the hospitalization memories.

This study has been cited as showing evidence for adult memory for events that occurred at the age of two, which is earlier than previous studies suggested. The evidence presented in this study must be carefully considered before making any conclusions. The number of participants who responded positively to the sibling birth questions was few and many were unverified. It has been suggested that they also may have used family knowledge to aid their recall as well as the limited range of possible answers to the questions. For example, a question asked what the baby was doing when you first saw him or her and most people know that newborns spend most of their time sleeping, eating or crying.

Eacott and Crawley (1998) implemented a study that improves on some of the weaknesses from Usher and Neisser’s experiment. They felt it was important to factor out the family knowledge and use a larger number of respondents in order to get a better representation of the age at which we retain our first memories. To account for the family knowledge, Eacott and Crawley questioned both the older and younger sibling. The older sibling was asked “Who looked after you when your mother was in the hospital (giving birth to the younger sibling)?” The younger brother or sister was then asked, “Who looked after your older sibling when your mother was in the hospital”? The comparison of these two answers can give us an assessment as to the degree that family knowledge is playing in the former response. A larger group of participants who were between the ages of two and three at the time of their siblings’ birth was used to improve the significance of the results (n=700). Two groups of participants made up of elder and younger siblings were compared with a questionnaire similar to the one used by Usher and Neisser (1993). One group was asked to use their memories as well as their family knowledge to answer the questions (called the report group), whereas the other was instructed to only use actual memories in their responses (recall group).

The results of this study suggest several relevant findings. The first is that the pattern of data collected was mostly in line with Usher and Neisser’s (1993) findings. Approximately 75% of the participants who could recall something about their sibling’s birth were between the ages of 28 and 35 at that time. The candidates who were between the ages of 24 and 27 months at the time of their sibling’s birth remembered significantly less than those in the 28 to 35 month range. The data obtained from this procedure led the experimenters to believe the recall group used actual memories as opposed to a combination of knowledge and memory. The degree of error determined by the subject’s mother was greater for the report group than for recall, 20% and 13% respectively. The greatest weakness of this experiment was the lack of randomness in choosing the participants. They were all college or university students and likely were above the average intelligence. This could have contributed to the early age at which events were remembered. If a sample from the general population were used, the mean age would conceivably go up. In reference to these two experiments, we can conclude that an event, which occurs when you are under three years old, can be recalled in adulthood. More interestingly though, was the display of substantial memory from two and a half years of age while memory from the first quarter of the second year is quite scarce. While these experiments provide no explanation for the occurrence of childhood amnesia, they do provide some illustration about the nature of the phenomenon itself.

Mechanisms Contributing to Childhood Amnesia:

The explanations for why childhood amnesia occurs are many. They range from a physiological basis to a lack of self-concept. The fact that human memory has many aspects, localized in different areas of the brain is well documented. The following information, combined with the empirical evidence related to the phenomenon leads me to believe that there are multiple systems responsible for its occurrence.

Some early theories proposed that the failure to remember anything before the age of three was due to an immature nervous system and subsequently, the underdeveloped hippocampus. This theory cites a storage failure for the memory deficiencies including perceptual or neurological immaturity and inadequate encoding. The hippocampus has been shown to play an important part in the storage of long-term memories and it is not fully developed before age three. Nelson (1995) has studied the development of several structures in the brain and linked them with specific classifications of memory. The developmental approach to the emergence of memory systems states that a form of preexplicit memory dependant on the hippocampus is developed in the first few months of life. At the age of eight to twelve months, when the limbic and cortical structures mature a little more, explicit memory begins to evolve. Procedural learning and conditioned learning emerge very early and can be seen in newborn babies. The prefrontal lobe of the brain starts to become more adultlike in the second year of life and this is when we see the commencement of working memory. Nelson (1995 & 1993) suggested that working memory must have been functioning for long term memories to be stored accurately.

However if the cause of childhood amnesia is the underdevelopment of the brain, then we would expect that a three-year-old child would not remember anything from six months to one year prior. Howe and Courage (1993 & 1997) collected evidence to the contrary. They found that children of this age could consistently and accurately remember events that had occurred for up to one year in the past. These findings are also consistent with the data from the Fivush and Schwarzmueller 1998 study that illustrates that children remember childhood events better than when they are adults even when a normal forgetting curve is used to compensate for the extended time interval. In response to this and other evidence some psychologists have proposed that childhood amnesia is effected more by retrieval failure than by storage failure.

Howe and Courage (1997) suggest one possible explanation for the failure to retrieve childhood memories. It states that the schemata used to evaluate a situation and thus what you will remember about it, changes so drastically from childhood into adulthood, that the earlier memories no longer fit with one’s present knowledge. In other words, what you may remember does not fit your adult schema thus does not make sense and so it is not integrated with what you now call memory. We can deduce much of this logically. Children remember differently than adults. For example, a child may remember the spicy onion on his or her hotdog at a baseball game rather than the game winning, grand slam homerun. Eventually, these process changes and the taste of an onion is fairly common and does not merit any long-term memory.

Another interesting, though essentially untestable, (except for coorelational studies) explanation for childhood amnesia is the development of the ‘cognitive-self’ (Howe & Courage, 1997; McKee & Squire, 1993). The emergence of the cognitive-self just so happens to develop at the same time that most people have their first childhood memories. The theory basically states that humans cannot have memories about one-self until the stage in their development when they recognize that they are separate and distinct from their environment. This usually happens at around the age of two and is evaluated by the ‘Rouge test’. The rouge test is when a child is placed in front of a mirror with a red dot on their nose. If the child recognizes him/herself, he/she will reach for their nose. If, however, the child has not developed to the point of self-recognition, he or she will likely reach for the image of the red dot in the mirror. Most of our memories involve the presence of something that happens to ‘me’ and if we do not have a sense of ‘me’ yet, then it is unlikely to remember such events. The events remembered before the recognition of the cognitive self will be so vastly different than our other memories that they probably will not be recalled. The recognition of one self does not suddenly appear at 18-24 months of age but rather it gradually begins organizing itself from birth but does not become fully active until this time. This helps explain why there are some memories for very young children for events that occur before the critical age of two to three years. The autobiographical aspect of memory seems to be vital for information stored for long periods of time. This touches on humans’ egocentricity that an event is not important unless it happens to ‘me’.

There is also another important aspect of human memory that develops at approximately the same time as the offset of childhood amnesia. The development of language and specifically inner speech is hypothesized to play an important role in the development of autobiographical memory (Howe & Courage, 1993). The association is made because of the synchronization of the timing of the two events and the logical fact that participants must make use of language to communicate memories. The action of inner speech is necessary for rehearsal strategies. The use of language undoubtedly helps organize past events into terms comprehensible to many. The study by Fivush, Haden and Adam (1995) illustrates how children’s narratives about the same event become more elaborate and more complex over time, especially between the ages of four and five years. This lends evidence to the idea that more elaborate encoding of memories is only present in the years after three. This also fits with the concept that; the more encoding associated with a memory, the greater chance that it can be recalled during adulthood. It seems that only those memories that can be discussed with others will become part of the autobiographical life story. The findings in this study (Fivush, Haden & Adam, 1995) indicate that memory of events occurring before children are able to relate these memories verbally will be extremely vulnerable to loss.

Conclusion:

There are many confounding factors contributing to the limited empirical evidence relating to the causes of childhood amnesia. In fact, there is far more evidence against each causation theory in comparison to the supporting evidence. Presently we have to settle for information concerning the nature of the phenomenon itself instead of explanations of exactly why it happens. It is through these behavioral observations and the continued study that we will gain insight and new hypotheses concerning this topic.

I personally believe that it is a good thing we no not remember our earliest years. Memories of crying, not being able to communicate well, the birthing process, immunization, circumcision (for some unlucky children) and not having any control over your environment are probably best forgotten. Perhaps Freud was right in saying that these memories are suppressed because of the extreme unpleasantness of many events surrounding these years.

My theory on childhood amnesia is that it is a possible adaptive function stemming from evolution. Although, I have not found any formal research on this view (or empirical evidence to support my claim), it is plausible that not having explicit memory of the first years is helpful to human development. Other than the blocking of unpleasantness, childhood amnesia may be helpful such that all of the brain’s resources are devoted to growth and adaptation to the new environment. The long-term memory process may draw on the brain’s limited resources during these critical years and the absence of this allows the brain to progress more quickly in vitally important areas such as communication skills and locomotion.

It is important to note that the differing views with respect to the cause of childhood amnesia are not mutually exclusive. The evidence that I have studied in this field points to a composite origin of childhood amnesia. Dualistic theories have dominated many areas of modern psychology. The extremist views of psychologists are usually combined (eventually) into some middle ground with everyone agreeing that many factors contribute to any psychological phenomenon. This topic proves to be no different. The role of language development in autobiographical memory is well documented and certainly contributes to childhood memories. It is also believed that humans must learn to have a sense of one-self before memory related to themselves can be retained. The development of the brain is also important because of at least two factors. The first is that the perception of events that occur in childhood are different from those in adulthood because of the dramatic changes in structure, connections and maturity of the brain. The second regards the lack of functional capabilities present during this time period. We do have evidence that suggests infants do retain information for long periods of time so we can conclude that some mechanisms for storage of memory exist in the first few months of life.

The only solid evidence regarding this phenomenon is the age at which adults can recall their first experiences (approximately three years old). There is no dispute that the first three years of life are essential to the development and growth throughout the rest of childhood and adolescence. In reference to this fact, it is quite odd that we can remember very few specific events from this time frame. Perhaps the only the most important knowledge is retained; the implicit, procedural and motor knowledge that will aid us for the rest of our lives.