Serial position effect: what is this psychological phenomenon?

This cognitive effect was studied by psychologist Hermann Ebbinghaus.

People tend to remember better the first and last item of a list when they are asked to read it or listen to it in order to say it later. when we are asked to read it or listen to it in order to say it later.

This phenomenon is known as the serial position effect and is related to the way we encode and store our memories in short- and long-term memory.

In this article we explain what is the serial position effect, what is the primacy effect and the recency effect, and what is the theoretical model on which it is based.

• Recommended article: "10 psychological phenomena that will surprise you".

What is the serial position effect?

The serial position effect occurs when we try to remember the items in a list and those at the beginning and at the end are remembered better than the items in the middle. This phenomenon was originally studied by Hermann Ebbinghaus, a German psychologist and pioneer in the use of the experimental method to study the functioning of human memory.

The tendency to better remember the first items in a list is called the primacy effect.and the greater probability of remembering the last items is called the recency effect. If this probability is plotted, a U-shaped curve is obtained that represents the precision with which memories vary as a function of the position of the items in a list.

This phenomenon is based on an experiment in which first, a subject is read a list with a given number of items (unrelated to each other and greater than seven) and asked to listen to it carefully; and second, they are asked to write down the items on the list that they remember in any order (free recall). The result usually corroborates the serial position effect, as well as the primacy and recency effects that we explain below.

When the items are visual stimuli, those presented at the beginning exert a greater influence; not only are they better remembered, but they also interfere with the recall of later items. In the case of auditory stimuli, it is the items at the end that exert the greatest influence; however, if several presentations of information are made separated in time and the subject must make a decision shortly after the last presentation, the recency effect usually has more influence on the decision.

The serial position effect also generates a general selection preference known as the order effectThe serial position effect: we are more likely to select the first and last items in a list than the items in the middle (e.g., as with the order of candidates in a ballot).

The primacy effect

The primacy effect, as we have discussed above, occurs when we are presented with a list of several items and then, as we list the items, we remember them, when listing the items, we remember better the ones at the beginning of the list.. This phenomenon occurs because the initial items are better stored in our long-term memory (LTM) than the later items. In fact, in lists where items are presented quickly, the primacy effect is weaker, as we have less time to store them in the LTM.

The evidence that the information that appears first is more likely to be recalled later can also be explained by the fact that there is more time for those first items to be repeated more times than the others, and therefore, there is more likely to be a transfer of information from short-term memory to the LTM.

The primacy effect also affects us in judging people.. In studies conducted by psychologist Solomon Asch, a list of words was listed in different order in order to describe the character of another person. When positive adjectives were placed at the top (p. e.g., "smart, hard-working, selfish and stubborn"), participants tended to judge the other person positively.

However, the phenomenon of primacy in how we judge other people and how they generate first impressions may also be related to attentional capacity and to the fact that when we first meet someone we tend to be alert, and the first memory always tends to have a more intense affective tinge, which facilitates its consolidation in the long term (we tend to remember better the experiences that have a greater emotional charge).

The recency effect

The recency effect occurs when we better remember the last items on a list.. This occurs because when we are asked to recall that list, the last items still remain in our working memory and are therefore more available and can be accessed more quickly.

This phenomenon is not affected by the rate of presentation of the items, but is affected by the passage of time and by the exposure to additional information. For example, the recency effect disappears when the subject is forced to think of anything else 30 seconds after the last item in the list is presented. This is something that does not occur with the primacy effect, since in that case the information has already been stored in long-term memory, something that does not occur with the recency phenomenon.

The temporal context in which stimuli or items in a list are presented could also be related to the occurrence of the recency effect. Such a context could serve as a cue for the subject to retrieve stored information, a fact that would explain why more recent items that were processed in a different temporal context (earlier in the list) are more likely to be recalled.

On the other hand, this effect disappears or is substantially reduced when an interference task, involving working memory, is introduced. Therefore, distractor stimuli (if they exceed 15 to 30 seconds in duration) can completely nullify this effect. Moreover, if recall occurs immediately after the last item is presented, the recency phenomenon is constant, regardless of the length of the list or the rate of item presentation.

Atkinson and Shiffrin's memory model

Both recency and primacy effects have been interpreted on the basis of Atkinson and Shiffrin's multistore memory model.. This theoretical model postulates that such effects reflect the operations of two independent memory systems, including short-term memory (or working memory) and long-term memory, plus another sensory memory store.

The short-term memory store has a duration of less than 30 seconds, unless attention is paid to the information contained therein and it is reprocessed (e.g., by repetition). George A. Miller studied this type of memory and concluded that in that period of time we can learn seven pieces of information (plus or minus two). However, this figure has been questioned and it is believed that it may vary according to conditions.

Regarding long-term memory, Atkinson and Shiffrin's model postulates that it is a store to which information coming from short-term memory is transferred, provided it is processed fast enough. According to the authors, this store would have a limited capacity and could last a lifetime. This would mean that we maintain relatively intact the capacity to store new information.

Finally, with regard to sensory memory, the model indicates that this store is responsible for retaining information that does not filter our attention and is not processed correctly. There are two types: iconic or visual, which lasts approximately 500 milliseconds; and echoic or auditory, which lasts between three and four seconds.

However, although Atkinson and Shiffrin's memory model is still useful for explaining certain phenomena, such as the serial position effect, other theoretical models that complement and extend the multi-store model, such as the processing models or thesuch as processing models or connectionist models.

Bibliographical references:

• Anderson, N. H. (1965). Primacy effects in personality impression formation using a generalized order effect paradigm. Journal of personality and social psychology, 2(1), 1.

• Glenberg, A. M., & Ramos, Á. F. (1991). Superior recuerdo de ítems iniciales en la modalidad visual: una explicación basada en la recuperación. Cognitiva, 3(1), 123-141.

• Murdock Jr, B. B. (1962). The serial position effect of free recall. Journal of experimental psychology, 64(5), 482.