Chunking (psychology)

In cognitive psychology, chunking is a process by which individual pieces of an information set are broken down and then grouped together. A chunk is a collection of basic familiar units that have been grouped together and stored in a person's memory. These chunks are able to be retrieved more easily due to their coherent familiarity. It is believed that individuals create higher order cognitive representations of the items within the chunk. The items are more easily remembered as a group than as the individual items themselves. These chunks can be highly subjective because they rely on an individuals perceptions and past experiences, that are able to be linked to the information set. The size of the chunks generally range anywhere from two to six items, but often differ based on language and culture.It is a little dramatic to watch a person get 40 binary digits in a row and then repeat them back without error. However, if you think of this merely as a mnemonic trick for extending the memory span, you will miss the more important point that is implicit in nearly all such mnemonic devices. The point is that recoding is an extremely powerful weapon for increasing the amount of information that we can deal with. In cognitive psychology, chunking is a process by which individual pieces of an information set are broken down and then grouped together. A chunk is a collection of basic familiar units that have been grouped together and stored in a person's memory. These chunks are able to be retrieved more easily due to their coherent familiarity. It is believed that individuals create higher order cognitive representations of the items within the chunk. The items are more easily remembered as a group than as the individual items themselves. These chunks can be highly subjective because they rely on an individuals perceptions and past experiences, that are able to be linked to the information set. The size of the chunks generally range anywhere from two to six items, but often differ based on language and culture. The phenomenon of chunking as a memory mechanism is easily 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. It would be stored as December 10th, 1946 instead of a string of numbers. 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 than visual presentation does. Previous literature, such as George Miller's The Magical Number Seven, Plus or Minus Two: Some Limits on our Capacity for Processing Information (1956) has shown that the probability of recall of information 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 since the groups produced have meaning to the participant, 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 skilled memory effects' section below. The word chunking comes from a famous 1956 paper by George A. Miller, 'The Magical Number Seven, Plus or Minus Two: Some Limits on Our Capacity for Processing Information' (Neisser, 1967). At a time when information theory was beginning to be applied in psychology, Miller observed that some human cognitive tasks fit the model of a 'channel capacity' characterized by a roughly constant capacity in bits, but short-term memory did not. A variety of studies could be summarized by saying that short-term memory had a capacity of about 'seven plus-or-minus two' chunks. Miller (1956) wrote, 'With binary items the span is about nine and, although it drops to about five with monosyllabic English words, the difference is far less than the hypothesis of constant information would require (see also, memory span). The span of immediate memory seems to be almost independent of the number of bits per chunk, at least over the range that has been examined to date.' Miller acknowledged that 'we are not very definite about what constitutes a chunk of information' Miller (1956) noted that according to this theory, it should be possible to increase short-term memory for low-information-content items effectively by mentally recoding them into a smaller number of high-information-content items. 'A man just beginning to learn radio-telegraphic code hears each dit and dah as a separate chunk. Soon he is able to organize these sounds into letters and then he can deal with the letters as chunks. Then the letters organize themselves as words, which are still larger chunks, and he begins to hear whole phrases.' Thus, a telegrapher can effectively 'remember' several dozen dits and dahs as a single phrase. Naive subjects can remember about only nine binary items, but Miller reports a 1954 experiment in which people were trained to listen to a string of binary digits and (in one case) mentally group them into groups of five, recode each group into a name (for example, 'twenty-one' for 10101), and remember the names. With sufficient drill, people found it possible to remember as many as forty binary digits. Miller wrote: