The serial position effect refers to the finding that recall accuracy varies as a function of an item's position within a study list. When asked to recall a list of items in any order (free recall), people tend to begin recall with the end of the list, recalling those items best (the recency effect). Among earlier list items, the first few items are recalled more frequently than the middle items (the primacy effect). See and for details.

One suggested reason for the primacy effect is that the initial items presented are most effectively stored in long-term memory because of the greater amount of processing devoted to them. (The first list item can be rehearsed by itself; the second must be rehearsed along with the first, the third along with the first and second, and so on.) One suggested reason for the recency effect is that these items are still present in working memory when recall is solicited. Items that benefit from neither (the middle items) are recalled most poorly.

There is experimental support for these explanations. For example:

• The primacy effect (but not the recency effect) is reduced when items are presented quickly and is enhanced when presented slowly (factors that reduce and enhance processing of each item and thus permanent storage)
• The recency effect (but not the primacy effect) is reduced when an interfering task is given; for example, subjects may be asked to compute a math problem in their heads prior to recalling list items; this task requires working memory and interferes with any list items being attended to
• Amnesiacs with poor ability to form permanent long-term memories do not show a primacy effect, but do show a recency effect

Primacy effect

The primacy effect, in psychology and sociology, is a cognitive bias that results from disproportionate salience of initial stimuli or observations. If, for example, a subject reads a sufficiently long list of words, he or she is more likely to remember words read toward the beginning than words read in the middle.

The phenomenon is said to be due to the fact that the short term memory at the beginning of whatever sequence of events is being presented, is far less 'crowded' and that since there are far fewer items being processed in the brain at the time when presented than later, there is more time for rehearsal or pondering of the stimuli which can cause them to be 'transferred' to the long term memory for longer storage.

The recency effect is comparable to the primacy effect, but for final stimuli or observations. Taken together the primacy effect and the recency effect predict that, in a list of items, the ones most likely to be remembered are the items near the beginning and the end of the list (serial position effect). Lawyers scheduling the appearance of witnesses for court testimony, and managers scheduling a list of speakers at a conference, take advantage of these effects when they put speakers they wish to emphasize at the very beginning or the very end of a long list.

Recency effect

The recency effect, in psychology, is a cognitive bias that results from disproportionate salience of recent stimuli or observations. People tend to recall items that were at the end on a list rather than items that were in the middle on a list. For example, if a driver sees an equal total number of red cars as blue cars during a long journey, but there happens to be a glut of red cars at the end of the journey, he or she is likely to conclude that there were more red cars than blue cars throughout the drive.

The inverse of this effect is the primacy effect. The recency effect is compatible with the peak-end rule.

Furthermore, the effect also refers to the effect in autobiographical memory that people recall more recent than remote personal events.

Another example of the recency effect is applied by lawyers. The key witnesses will go at the end of list (or the beginning to take advantage of the primacy effect), so the jury will keep them in mind while they deliberate.

Studies include:

• Glanzer and Cunitz (1966)
• Atkinson and Shiffrin (1968)
• Ebbinghaus, various
• Murdock (1962)

Related effects

In 1977, William Crano decided to outline a study to further the previous conclusions on the nature of order effects, in particular those of primacy v. recency, which were said to be unambiguous and opposed in their predictions. The specifics tested by Crano were:Change of meaning hypothesis: “adjectives presented first on a stimulus list established a set, or expectation, through which the meanings of the later descriptors were modified in an attempt to maintain consistency in the mind of the receiver.”Inconsistency discounting: “later descriptions on the stimulus list were discounted if inconsistent with earlier trait adjectives.”Attention decrement hypothesis: “earlier adjectives would wield considerably more influence than the later ones, and a primacy effect in the typical impression formation task would be expected to occur…even when the stimulus list contains traits of a high degree of consistency.”

See also

• Clive Wearing
• HM (patient)
• Learning curve
• Law of primacy in persuasion
• List of memory biases
• List of cognitive biases
• Principles of learning
• Baader-Meinhof Phenomenon

Further reading

• Luchins, Abraham S. (1959) Primacy-recency in impression formation

References

• Frensch, P. A. (1994). Composition during serial learning: a serial position effect. Journal of Experimental Psychology: Learning, Memory, and Cognition, 20, 2, 423-443.
• Healy, A. F., Havas, D. A., & Parkour, J. T. (2000). Comparing serial position effects in semantic and episodic memory using reconstruction of order tasks. Journal of Memory and Language, 42, 147-167.
• Murray Glanzer and Anita R. Cunitz, "Two storage mechanisms in Free Recall", Journal of Verbal Learning and Verbal Behaviour, 1966