Source: Laboratory of Jonathan Flombaum—Johns Hopkins University

Why is it relatively hard to remember everything on a shopping list if it includes more than just a handful of items? Why is it possible to remember a phone number that one just heard, but not two or three phone numbers at once? Why is it difficult to remember names when several new people are introduced at the same time?

The answer has to do with the fact that over short-durations people rely on a specialized memory system called working memory. Unlike long-term memory, working memory has a very limited capacity. It is there so that information can be kept in mind, studied, manipulated, and then transferred to other memory and cognitive systems. But in order to serve in this active role, it needs to be selective, admitting only limited amounts of information at a time.

Experimental psychologists tend to think that people possess independent working memory systems for different kinds of information, with a major division between verbal and visual information. Each of these systems has an independent capacity limit.

To measure a person’s verbal working memory capacity limit—often called, his or her memory span—experimental psychologists often use a verbal list paradigm.

This video will demonstrate the measurement of verbal working memory span using a verbal list paradigm.