Many studies, dating back to the pioneering work of the psychologist Ebbinghaus in 1885, have shown that we forget as much as 80% of everything we read within 24 hours. Since then our understanding of human memory has increased dramatically. However, memory cannot be observed directly and its existence is inferred by psychologists who use a variety of techniques to study memory, including controlled laboratory experiments, quasi-experiments and field experiments as well as diary studies and cross-sectional studies. This paper aims to evaluate two different approaches in the study of memory: Marigold Linton’s (1975) autobiographical memory research using diary studies and Bahrick et al. (1975) quasi-experiment research on enduring memories.
The quasi-experiment method is mainly characterized by two unique features: the absence of control over all variables, as the experimenter does not manipulate the independent variable and the allocation of participants which are not randomized. Therefore this empirical approach can not be considered a typical experiment. Bahrick et al. (1975) studied enduring memories using a quasi-experiment design which involved 392 participants ranging in age from 17 to 74 years. Participants were divided into nine groups according to the elapsed time since graduation. This variation in age was important so that the time interval between initial learning phase and test phase varied, this being the independent variable. A cross- sectional design was used in this experiment since the participants chosen represented the different levels of the variable under investigation. The aim of the study was to test the enduring memory of the participants in relation to their former classmates. For this, the researchers used each person’s high school yearbook. They designed different kinds of memory tasks, such as former classmates’ face recognition, matching the appropriate name with the face of the classmate from a list of five other names or faces. Another task required the participants to recall the name of the classmate whenever a card showing a face was shown. Bahrick and his team also asked the participants to recall as many names as possible with no clues provided. The study revealed a decline in recall and recognition in the very oldest group of participants and also recognition was better than free recall. (as cited in Brace N., Roth I. 2002. pp. 136-8).
Another way psychologists have studied memory is to experiment on themselves. In a Diary Study approach, the participant is asked to record events from his or her own life for some period and after a fixed time interval is given a test for what actually happened. There are many variables of interest; a few common ones include the time interval between recording and testing, the types of to-be-remembered events, the types of retrieval cues provided at test, and the remembered vividness of the events. Variations on diary studies include using randomly set pages to cue recording of to-be-remembered events and having roommates to select and record events that may be tested at a later point (Thompson, 1982). (as cited in Weiner et al., 2003, p.486)
Marigold Linton (1975) investigated autobiographical study using a memory diary to record events of her life during 6 years. The researcher would randomly select pairs of records once a month and try to estimate the chronological order in which they had occurred and the date of each recorded event. The events were recorded according to their relevance and emotionality both at the time of the recording and the time of recall. The average of items tested each month was 150, from an amass of 5,500 items in total after 6 years.
Linton found that in the final year of the study 30 percent of the events recorded had been forgotten and her memory for real-life events decreased at a rate of 5 percent a year. One important finding was that the she did not detect any strong relationship between rated importance and emotionality, and later recall. Furthermore, Linton also noticed how difficult it was to make accurate and stable judgments about the long-term significance of events (as cited in Weiner et al., 2003. p.486).
Bahrick’s and Linton’s research have contributed to the study of memory in a variety of ways. Bahrick’s quasi-experiment study showed that we are better at remembering something by recognition rather than recall. Our memories, therefore can last a very long time, however, this study also shows that our long term memory (LTM) is not a permanent fixture and can fade with the passage of time, meaning that our memory for recollection can get worse, as we get older. Previous studies and experiments had shown that much of what we store in our memory is unmemorable information and therefore, making it hard for a person to remember and recall certain information. By using meaningful information from each participant, Bahrick was aiming to avoid past studies in the hopes that a person would be able to tap into their very-long term memory (as cited in Brace & Roth, 2002. pp. 136-138).
Although high in ecological validity, the lack of random assignment of participants in Bahrick’s study may pose many challenges for the investigator in terms of internal validity. The reason for that is it makes it harder to rule out confounding variables and introduces new threats to internal validity. In the present study, Bahrick and his team used statistical control to check uncontrolled variables such as whether participants stayed in contact with their former classmates along the years and whether they had the habit to go over their yearbook album frequently, they were not confounding variables.
Another critique made about Bahrick’s experiment flags the unclear reasons for the drop in recall since this could be due to the time lapse between the learning period and the retrieval of information or the drop of recall may have happened because of confounding variables such as physical aging. According to Nilsson (2003), all available evidence from cross-sectional research shows that there is a linear, decreasing memory performance as a function of age for episodic memory. Longitudinal studies suggest, however, that this age deficit may be an overestimation, by showing a relatively stable performance level up to middle age, followed by a sharp decline.
As with Linton’s diary study, it was found that our autobiographical memory is organized in more ways than just a timeline; a sign of progress in the introduction of effect into that organization (as cited in Rubin, 1988. p.6). Linton noted a tendency to forget the more unpleasant events. Baddeley (1993) writes that Linton also noted that rehearsal was playing an important role since the items picked out at random for testing that had been picked out before were better remembered
Brace and Roth (2002) writes that Linton argued that remembered events were salient, emotional and relative distinctive, and that there was some tendency for positive events to be better remembered. Thus her conclusions are consistent with those of other researchers who proposed that autobiographical memories are organized hierarchically, with interlocking structures of time periods and themes. Another interesting finding of Linton’s study is that as in Lab studies of words and pictures, forgetting of autobiographical events increased over time. She noted that once salient events became less memorable as she experienced more and more similar life events, corresponding to how the study of related material in laboratory experiments increases interference effects and leads to an abstraction of the gist of events or a schema for the events.
In the studies following Linton’s findings, two other diary researches performed by White (1982) and Wagenaar (1986) corresponded well with Linton’s observations: recalled events were unique, and, at least in Wagenaar’s study, more emotional. Both studies also presented some evidence for the better recall of pleasant events. (as cited in Weiner et al., 2002. pp 20-23)
There are many critical points made by researchers on the validity of Diary Study as a way to study autobiographical memories. Healy et al. (2003) observed three aspects which this approach may demonstrate some relevant flaws: a) the selection of the recorded events is totally controlled by the experimenter who will work as a filter regarding what events get recorded which may influence later recall; b) the effect of recording may work as an enhancer, making the events more memorable; and finally the effect that some events are more intensive and therefore easier to remember. According to Weiner et al. (2003), people continue to talk and think about life events long after their occurrence, and such rehearsal will have consequences for the way the events are remembered whereas in laboratory rehearsal instructions typically emphasize accuracy, no guidelines constrain the way people talk about their own lives.