Primacy Effect

The primacy effect is one aspect of a well-known phenomenon called the “serial position effect,” which occurs when one is asked to recall information from memory. The other aspect of the serial position effect is the recency effect. Psychologists discovered these effects more than a century ago; for example, in the 1890s, Mary Whilton Calkins experimented with these effects while she was a student of William James. Essentially, the serial position effect means that the recall of a list of items is easiest for a few items at the end of the list and for a few items at the beginning of the list. The recall of items in the middle of the list is generally poor. The primacy effect refers to the recall of items at the beginning of the list, while the recency effect refers to the recall of items at the end of the list. If one graphed the number of recalled items as a function of position in the list, one would obtain a U-shaped function.

Suppose that an experiment were performed in which the following list of 24 words was read aloud at the rate of one word per second to a group of persons:

apple, basketball, cat, couch, potato, book, bus, lamp, pencil, glasses, guitar, truck, photo, rose, apartment, movie, clock, car, dog, bowl, shoe, bicycle, plane, university

The individuals who had listened to the words being read aloud were then asked to write down all [Page 610]the words that they could remember. According to the serial position effect, the recency effect would predict that the terms university, plane, and bicycle would be easily recalled; in addition, the primacy effect would predict that the terms apple, basketball, and cat would also be easily recalled. However, items in the middle of the list, such as guitar, movie, photo, and rose would be least likely to be remembered.

The only exception to this principal occurs when an item in the middle of the list is extremely well known. For instance, suppose that one were asked to write down all the presidents of the United States that one could recall. The primacy and recency effects are still in evidence; that is, the current president and a few preceding ones are easily recalled, as are several of the first few presidents of the United States. But in this case, Abraham Lincoln is so famous that although his presidency occurred in the middle of the list, he tends to be very easily recalled. And because he is so well known, the presidents associated with him chronologically also tend to have elevated probabilities of being recalled. In this case, the graph of the recall frequency of presidents in chronological order includes two U-shaped graphs, one following the other, where Lincoln represents the peak in the middle of the list of presidents. This is known as the von Restorff effect and was discovered in 1933. It does not matter whether research participants are asked to write down all of the presidents that they can remember (a free recall task) or whether they are asked to write down the presidents in order of their respective terms in office; in both cases, the von Restorff effect occurs.

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