Hockenbury Discovering Psychology 5th txtbk

Introduction: What Is Memory?237second letter sequence was perceived as only four “chunks” of information, whichyou easily remembered: DVD, FBI, USA, and CIA. Thus, chunking can increasethe amount of information held in short-term memory. But to do so, chunking alsooften involves the retrieval of meaningful information from long-term memory, suchas the meaning of the initials FBI (Ericsson & Kintsch, 1995).The basic principle of chunking is incorporated into many numbers that we needto remember. Long strings of identification numbers, such as Social Security numbersor credit card numbers, are usually broken up by hyphens so that you canchunk them easily.Not every memory researcher accepts that short-term memory is limited toexactly seven items, plus or minus two. Over the half-century since the publicationof Miller’s classic article, researchers have challenged the seven-item limit (Jonides& others, 2008; Cowan & others, 2007). Current research suggests that the true“magical number” is more likely to be four plus or minus one than seven plus orminus two (Cowan & others, 2007; Saults & Cowan, 2007).Cognitive psychologist Nelson Cowan (2001, 2005) believes that the type ofstimuli used in many short-term memory tests has led researchers to overestimateits capacity. Typically, such memory tests use lists of letters, numbers, or words.According to Cowan, many people automatically chunk such stimuli to help themremember them. For example, even seemingly random numbers may be easily associatedwith a date, an address, or another familiar number sequence.To overcome this tendency, Jeffrey Rouder and his colleagues (2008) used a simplevisual stimulus instead of a sequence of numbers, letters, or words. The memorytask? Remembering the position of colored squares on a computer screen. Inthis and similar studies, participants were able to hold only three or four items intheir short-term memory at a time. Thus, many researchers today believe that thecapacity of working memory is no more than about three to four items at a timewhen chunking is not an option (Saults & Cowan, 2007).Whether the “magic number” is four or seven, the point remains: Short-termmemory has a limited number of mental “slots” for information. Chunking canincrease the amount of information held in each slot, but the number of slots is stilllimited.From Short-Term Memory to Working MemoryOur discussion of the short-term memory store has so far focused on just one typeof information—verbal or acoustic codes, that is, speechlike stimuli that we canmentally recite. Lists of numbers, letters, words, or other items fall into this category.However, if you think about it, we also use our short-term memory to temporarilystore and manipulate other types of stimuli, such as visual images. Forexample, suppose you’re out shopping with a close friend who asks you whether youthink a particular chair will match her living room furniture. Before you respond,you need to call up and hold a mental image of her living room. You are surelyusing your short-term memory as you consider her question, but how?In this example, you are actively processing information in a short-term memorysystem that is often referred to as working memory. Although the terms workingmemory and short-term memory are sometimes used interchangeably, workingmemory refers to the active, conscious manipulation of temporarily stored information.Working memory is what you’re using when you engage in problem solving,reasoning, language comprehension, and mental comparisons. In contrast, shorttermmemory is more likely to be used when the focus is on simpler memoryprocesses, such as rehearsing lists of syllables, words, or numbers.The best-known model of working memory was developed by British psychologistAlan Baddeley. In Baddeley’s (1992, 2007) model of working memory,there are three main components, each of which can function independently (seeFigure 6.3 on the next page). One component, called the phonological loop, is specializedfor verbal material, such as lists of numbers or words. This is the aspect ofworking memoryThe temporary storage and active,conscious manipulation of informationneeded for complex cognitive tasks, suchas reasoning, learning, and problemsolving.“Did you ever start to do somethingand then forget what the heck it was?”The New Yorker Collection (c) 2007 by Charles Barsotti from TheCartoonbank.com. All Rights Reserved.