What's in a Name? The Multiple Meanings of “Chunk” and “Chunking”

The term chunk, denoting a unit, and the related term chunking, denoting a mechanism to construct that unit, are familiar terms within psychology and cognitive science. The Oxford English Dictionary provides several definitions for “chunk.” First, “a thick, more or less cuboidal, lump, cut off anything,” or, colloquially, “a large or substantial amount.” The Merriam-Webster dictionary provides similar definitions. OUP’s Oxford Dictionary alone gives a computer-related meaning: “a section of information or data.” It is in this context, a chunk as a section of information, that the word is used within psychology and cognitive science. In these fields, a chunk typically refers to a single unit built from several smaller elements, and chunking to the process of creating a chunk. Gobet et al. (2001, p. 236) define a chunk as “a collection of elements having strong associations with one another, but weak associations with elements within other chunks.” However, in different contexts and with different authors, these two terms are used with a variety of meanings, which are very often conflated, leading to considerable confusion. Table 1 provides a taxonomy of the main meanings of “chunk” and “chunking,” which will be used to structure this article. The multiplicity of meanings of the terms “chunk” and “chunking” in the literature raises a number of questions. Do these meanings refer to the same “things”? Do they simply reflect differences in the empirical domains studied? Are the same mechanisms involved? Is learning underpinned by the same processes? As we shall see, these meanings sometimes differ in considerable ways (e.g., when referring to conscious vs. unconscious mechanisms or labeling declarative vs. procedural knowledge structures), but researchers often cite them together as if they refer to the same theoretical objects. Thus, there is the danger that, while researchers in different fields think they refer to the same theoretical concepts, they actually have different structures and mechanisms in mind. This inevitably results in lack of communication, or even worse, miscommunication. The aim of this article is explicitly not to review the extensive literature on chunking, which would be impossible in such a short format, but to highlight some of the main meanings of the terms “chunk” and “chunking,” to discuss their commonalities and differences, and to argue that progress in our understanding of chunking will be difficult until researchers recognize these different meanings and are more precise in the way they refer to them.