Serial Position Curve

A variety of different memory tasks have revealed that not all items in a list were equally likely to be remembered.  For instance, a very common method used to study memory was the free recall experiment.  In this kind of experiment, subjects are presented a list of to-be-remembered items, which could be digits, words, or nonsense syllables.  At the end of the list, subjects are given a set period of time (e.g., two minutes) in which they write down as many of the presented items as they recall.  They can write these items down in any order, which is why the method is called free recall.  While the subject can recall items in any order that he or she pleases, the experimenter generally plots the probability that an item is correctly recalled as a function of its position in the list, producing what is known as a serial position curve (see Figure 5-1).  All things being equal, serial position curves routinely demonstrate, regardless of list length, a primacy effect in which the first three or four items in the list are better recalled than the middle items of the list.  Serial position curves also typically reveal a recency effect in which the last three or four items in the list are also better recalled than the middle items (e.g., Glanzer & Cunitz, 1966, Exp. 1; Postman & Phillips, 1965).

References: