Chunking (Memory)

Chunking is the cognitive process of grouping individual, separate pieces of information into larger, more meaningful combined units, called chunks, in order to hold more total information in short-term or working memory than would otherwise be possible if each piece were held separately. The psychologist George Miller described the underlying principle in his highly influential 1956 paper The Magical Number Seven, Plus or Minus Two, in which he proposed that short-term memory is limited to holding roughly seven items, plus or minus two, regardless of how much information each individual item itself contains, meaning that recoding several small pieces of information into one larger meaningful chunk effectively increases the total amount of raw information a person can retain. A commonly cited illustration is a ten-digit telephone number, which is difficult to hold in memory as ten separate unrelated digits but becomes far more manageable once grouped into three familiar chunks, such as a three-digit area code followed by two smaller groups, and chess experts have similarly been shown, in classic studies by Adriaan de Groot and later by William Chase and Herbert Simon, to recall meaningful, realistic board positions far better than novices not because they hold more raw information but because years of experience let them recognize and encode entire recurring configurations of pieces as single familiar chunks. Because the effectiveness of chunking depends on a person's existing knowledge and familiarity with the material being grouped, the size and usefulness of the chunks a given person can form varies with expertise and provides one basis for teaching effective memorization and study strategies.