Operation Span
Introduction
In the memory span activity, you learned about the magical number seven and how immediate recall for isolated digits, letters, and words is limited to a range of between 5 and 9 (with an average of 7) in most people because the capacity of their short-term memory is limited. The memory span activity involved verbal material because the stimuli presented are easy to rehearse, assuming of course that you are fluent in the English language. The question addressed by this activity, the operation span, involves whether or not the resource that limits short-term memory is only related to verbal material, or do other processes like mathematical computation share the same resource.
Description of Activity
This operation span activity is inspired by the study of Turner and Engle from 1989 where span was estimated by alternating between the completion of multiple-step arithmetic problems and the presentation of simple words to be remembered. Trials in this activity begin with the usual fixation “+”. Focus on it and press the spacebar when you are ready to begin. You will then see an arithmetic problem, such as (8/2)+4=8, and respond by pressing “D” if it is correct or “K” if it is incorrect. Next you will be presented with a word that you must remember for recall later. A new arithmetic problem and another word will follow. Different trials contain different numbers of arithmetic problems followed by words. During each trial, make sure to say the arithmetic problems and words aloud as you read them. At the end of each trial, you will be shown a list of words arranged in a matrix that you have seen during the trial. Click on the words in the order they were presented to you.
How Does Arithmetic Processing Affect Span?
If the resource that limits short-term memory is only related to verbal material, what would you predict from the data that you generate during this activity? One prediction is that if the resource is only related to verbal material, then the arithmetic computation in between viewing the words should not consume that resource and your span for the words in this activity should be similar to your word span in the memory span activity. An alternative prediction is if the arithmetic processing does consume that limited cognitive resource, then doing the math problems will reduce your span. You were asked to state the arithmetic problems out loud during the task to ensure that you were actually doing them. For analysis of data in this activity, your memory performance will be calculated based on your memory performance for trials where you answered at least 85% of the arithmetic problems correctly. This is done to ensure that you were doing the math problems correctly most of the time. As you view your results and compare them to your word span from the memory span activity, you should be able to determine whether or not your data are compatible with the former or later prediction.
Operation Span and Cognitive Processing
Despite that mathematical processing was involved in the development of Turner and Engle’s estimate of operation span, they found that their estimate was positively correlated with skills including reading and comprehension that involve stringing together multiple words in sentences and paragraphs. The ability to read and understand complex passages depends on working memory. In long complex sentences, you need to keep in mind what you read in the beginning, so that what you read at the end makes sense. Turner and Engle found that those participants who have a higher working memory capacity as measured by a task like operation span also tend to have better reading and comprehension abilities. But it is important to note that working memory capacity is used for multiple types of cognitive processing, not just for verbal memory.