The serial position effect is a tendency to more accurately remember items at the beginning and end of a list, as opposed to items in the middle. This can play an important role in the acquisition of knowledge and can also be a factor when taking tests to assess cognitive function. Studies of this effect can be useful for activities such as the development of effective advertising materials, where the advertiser wants the target to remove key information after exposure to an advertisement.
Several different factors play a role in the serial position effect. One is primacy, where people have a better memory for information at the beginning of a list. At the other extreme, recency can play a role in how people remember lists, as the latest items will stick in their heads. Primacy tends to decrease when a subject rehearses all items on a list the same number of times, and recency is less common when time elapses between hearing the list and being asked to repeat it.
In the serial position effect, the subject may be more inclined to remember the beginning of the list due to primacy and the end due to recency. The accuracy of items in the middle is more doubtful, as the subject may have trouble storing and retrieving these memories. In something like a test of cognitive function, caregivers need to consider this effect. To address recency, for example, the caregiver can give the patient a list to remember and check two weeks later to see what items the client can remember.
In free recall, items at the beginning and end of the list may appear first due to the serial position effect. One way to ensure that a subject learns everything on the list is to mix up the order or ask the subject to try all the items multiple times. Consideration of the effect may also play a role in the presentation of the information; for example, a seven-digit phone number may be easier to remember than one with ten digits, and therefore it may be more common to exchange short numbers without an area code.
Other factors can influence the serial position effect. Distracting items can make it more difficult to store and recall memories. If the list is presented in different voices or fonts, for example, the subject may have a harder time with it. Similarly, environmental distractions such as loud noises or strong odors can distort the subject's memory.