Chunking in psychology is a process by which individual pieces of information are bound together into a meaningful whole (Neath & Surprenant, 2003). A chunk is defined as a familiar collection of more elementary units that have been inter-associated and stored in memory repeatedly and act as a coherent, integrated group when retrieved (Tulving & Craik, 2000).
It is believed that individuals create 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 ranges anywhere from two to six items, but differs based on language and culture
The phenomenon of chunking as a memory mechanism can be observed in the way individuals group numbers and information in the day-to-day life. For example, when recalling a number such as 12101946, if numbers are grouped as 12, 10 and 1946, a mnemonic is created for this number as a day, month and year. Similarly, another illustration of the limited capacity of working memory as suggested by George Miller can be seen from the following example: While recalling a mobile phone number such as 9849523450, we might break this into 98 495 234 50. Thus, instead of remembering 10 separate digits that is beyond the “seven plus-or-minus two” memory span, we are remembering four groups of numbers.
A modality effect is present in chunking. That is, the mechanism used to convey the list of items to the individual affects 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. Previous literature, such as George Miller’s The Magical Number Seven, Plus or Minus Two: Some Limits on our Capacity for Processing Information (1956) 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 used as a strategy, one can expect a higher proportion of correct recalls.
Various kinds of memory training systems and mnemonics include training and drill in specially-designed recoding or chunking schemes. Such systems existed before Miller’s paper, but there was no convenient term to describe the general strategy or substantive and reliable research. The term “chunking” is now often used in reference to these systems. As an illustration, patients with Alzheimer’s disease typically experience working memory deficits; chunking is an effective method to improve patients’ verbal working memory performance (Huntley, Bor, Hampshire, Owen, & Howard, 2011). Another classic example of chunking is discussed in the “Expertise and skill memory effects” section below.