Chunking (psychology)

Chunking (psychology)

Chunking, in psychology, is a phenomenon whereby individuals group responses when performing a memory task. Tests where individuals can demonstrate "chunking" commonly include serial and free recall tasks. All three tasks require the individual to reproduce items that he or she had previously been instructed to study. Test items generally include words, syllables, digits/numbers, or lists of letters. Presumably, individuals that exhibit the "chunking" process in their responses are forming clusters of responses based on the items' semantic relatedness or perceptual features. The chunks are often meaningful to the participant. It is believed that the assimilation of different items according to their properties occurs due to individuals creating higher order cognitive representations of the items on the list that are more easily remembered as a group than as individual items, themselves. Representations of these groupings are highly subjective, as they depend critically on the individual's perception of the features of the items and the individual’s semantic network. The size of the chunks generally range anywhere from two to six items, but differs based on language and culture. For example, Chinese speakers can remember up to ten digits because the number words are all single syllables. "Chunking" maintains a number of characteristics when observed in recall tasks.

The first characteristic is that, when individuals incorrectly recall an item in a serial recall task, it tends to come from a similar item. For example, it may be an item that they placed in the same grouping. Individuals that employ this strategy for recall will commonly misplace items they are grouping. Since one must recall items in the precise order they were presented during the serial recall task, any item that is even one position out of place is deemed incorrect. Therefore, according to how many groups an individual breaks the list into, misplacement of an item will be limited to within the confine of the size of the group.

Another feature of the "chunking" effect is that a modality effect is present. That is, the mechanism used to convey the list of items to the individual has an impact on how much "chunking" occurs. Experimentally, it has been found that auditory presentation results in a larger amount of grouping in the responses of individuals, as compared to visual presentation. Studies, such as George Miller’s The Magical Number Seven, Plus or Minus Two: Some Limits on our Capacity for Processing Information have shown that the probability of recall is greater when the "chunking" strategy is used. As stated above, the grouping of the responses occurs as individuals place them into categories according to their inter-relatedness based on semantic and perceptual properties. Lindley (1966) showed that the groups produced have meaning to the participant, therefore; this strategy makes it easier for an individual to recall and maintain information in memory during studies and testing. Therefore, when "chunking" is evident in recall tasks, one can expect a higher proportion of correct recalls.

The most convincing evidence for the existence of "chunking" is illustrated in the analysis of response times. When looking at this aspect of the test/response phase of a recall task, one observes response time as a function of output position. Therefore, this analysis allows for the measurement of the process of recall in each task participant. The recall or forgetting curve illustrate that each item in a cluster typically requires about the same amount of time to recall. This can be observed as strings of items where the response times are both similar, as well as very rapid. However, one can also see in these response time curves that the time between the "chunks" follows a different trend entirely. Items or periods of output where the individual is not recalling items that belong to a group require a significantly larger amount of time. Therefore, prior to the beginning and end of recall of a group of items in a "chunk," there is a jump in response time in the curve.