From the Research: Myths Worth Dispelling Seven Plus or Minus Two Jeanne Farrington, EdD S ometimes ideas that are in common use do not have the validity one might think given their ubiquity. It���s fairly easy to be caught up in the belief that something that seems logical or has been repeated often enough has evidence behind it that we might respect���even when it does not. Thepurposeofthiscolumnistogentlysuggestthatwe examineoursourcesofevidenceforsomemythsthathave beenrepeatedsooftenthattheyhavebecomeanaccepted part of the landscape (at least for some practitioners). The reason for revisiting these ideas is so that we can avoid using myths as the underpinnings for design- and performance-oriented decisions. Instead, we can make decisions based on more current evidence that should provide a firmer foundation for the choices we make. This column is offered without judgment toward anyone who has held an idea as true that was a misconception in the first place or that has been shown later to have little evidence to support it. Who has not been enamored with an idea that sounds so right but that later turns out to be something quite different? In this regular column, you will find a series of topics and issues that performance improvement professionals should take into account as they make decisions about what to provide for their learners or clients. For the first topic, we will take a look at the capacity of working memory. How often have you heard that we can hold seven items (plus or minus two) in our short-term memory? Short-term, or working, memory, is ������the collection of mental processes that permit information to be held temporarily in an accessible state, in the service of some mental task������ (Cowan, 1998, p. 77). 113 P E R F O R M A N C E I M P R O V E M E N T Q U A R T E R L Y , 2 3 ( 4 ) P P . 1 1 3 ��� 1 1 6 & 2011 International Society for Performance Improvement Published online in Wiley Online Library (wileyonlinelibrary.com). DOI: 10.1002/piq.20099 For over 50 years, seven plus or minus two has been a commonly used guideline for gauging how many chunks of new information should be presented at one time in learning and performance situations. Often cited as the limit of working memory, this guideline was created as a result of misinterpreting an article by Miller (1956). More recent studies suggest that the limit for working memory is more like three, and sometimes four, with various factors influencing the capacity of an individual���s working memory. Given too much novel infor- mation at one time, learners and per- formers can be derailed by cognitive overload. Instructional designers and performance consultants can adjust the presentation of new information to manage intrinsic, extraneous, and germane cognitive load. This column provides suggestions about how to reduce cognitive overload to improve learning and performance.

Givenalimittoourmentalcapacity,weruntheriskofsubjectinglearners or employees to cognitive overload if we expect them to remember or to process too much at once. If you are worried about cognitive overload, some say, just limit the presentation of ideas (or chunks) to seven. Limit lines on a PowerPoint slide to seven. Note the number of digits in a telephone number���seven (plus one chunk of three for the area code). Give people sevenactionitemstoworkonatatime.Organizeaprocesssothatithasseven steps. When something must be committed to memory, organize it into seven plus or minus two chunks. Where This Came From In 1956, George Miller wrote ������The Magical Number Seven, Plus or Minus Two,������ an article in which he noted the many times the number seven occurs���for example, seven days of the week, seven wonders of the ancient world, and the seven seas. The recurrence of the number seven, along with the article���s title, are commonly cited, and have become justification for creating rules for presentations, training, and other performance-enhancing programs. However, what tends to go unnoticed is Miller���s conclusion that all these sevens are probably nothing more than coincidence (Thomas, 2005). Does Miller say that there is a limit to our capacity to process information? Yes. Does he say that there are seven, plus or minus two, slots in short-term memory? No. (See Shriffrin & Nosofsky, 1994, for a review.) What to Consider Instead More recent sources agree that, yes, there is a limit to how many new elements we can hold in working memory (Clark, 2010 Cowan, 1998 Luck & Vogel, 1998). However, they suggest that the limit is more like three or some- timesfouritemsorchunks.Variousfactorsinfluenceworkingmemorycapacity (Kane &Engle, 2003 Shiffrin & Nosofsky, 1994), including the level of expertise of the learner or performer in a given domain (Ericsson & Kintsch, 1995). Designersshouldkeep inmind thattherelative size andcomplexity ofan element in working memory is vastly different for a novice than it is for an expert. For example, a novice at chess sees each separate piece as an item, whereas an expert may see the position of pieces on the entire board as one big chunk of information (Chi, 2006). Therefore, the mental effort required by one person to process a set of elements will be different���sometimes fundamentally so���from that required by another. Keeping in mind individual differences and expertise, we should probably avoid creating a new doctrine (������three, sometimes four������ versus ������seven plus or minustwo������).Themorerelevantruleistoavoidcreatingcognitiveoverloadfor learners and performers. Cognitive overload (Sweller, 1988) inhibits learning andproblemsolving,anditcanreducetheavailablespaceinworkingmemory enough to cause errors and reduce learning and performance. 114 DOI: 10.1002/piq Performance Improvement Quarterly