Operation Span Task (OSPAN)

Background

The Automated Operation Span Task (OSPAN) is a widely used measure of working memory created in 1989 by Marilyn Turner and Randy Engle at the University of South Carolina. The task was used along with the Counting Span Task and Daneman and Carpenter's Reading Span Task to show that the different tasks were sensitive to same underlying psychological construct.

Since its inception, the OSPAN has become a gold-standard laboratory measure of working memory. It's an important measure of individual differences and has emerged as one of the strongest predictors of fluid intelligence, reading comprehension, reasoning, problem solving, learning, and attention control.

Task Procedure

The OSPAN combines a letter-span task (participants recall a sequence of serially presented letters) with a simple math task (participants judge whether a solution to an arithmetic equation is true or false).

Letter Span Task

In the letter-span task, participants are shown, one at a time, a series of letters randomly drawn from a pool of 12, followed by a matrix of all 12 letters. They must the recall the sequence by clicking each letter in the order it was presented. Feedback is provided indicating the number of letters correctly recalled, with letters recalled in the wrong position treated as incorrect.

Math Task

In the math task, participants are shown an arithmetic equation (e.g. "8/2 + 3") and are instructed to click the mouse button once they've solved it. A new screen appears with a proposed solution and two response buttons labeled "TRUE" and "FALSE", which they must click to indicate whether the solution is correct. Feedback is then provided indicating if their response was correct. A timeout of 5000 is imposed during practice. The timeout is adjusted up or down for the test phase depending on practice performance.

During the practice phase, participants perform the letter-span followed by the math task. During the test phase, the two tasks are combined such that each presented letter is immediately followed by a math problem. After all letters in the sequence (and subsequent math problems) have been presented, the letter matrix is displayed and participants must recall the letter sequence. During the test phase, feedback is given on letter recall but not on the math task.

What it Measures

The OSPAN is a measure of working memory capacity.

Psychological domains

• Executive Functioning
• Working Memory: Working memory maintenance during active processing of distracting information
• Fluid Intelligence: Strongly correlated (.45 - .55) with Gf

Main Performance Metrics

• OSPAN Score: Total number of correct letters recalled in the correct position in perfectly recalled sets
• Partial-credit unit (PCU): Total number of correct letters recalled relative to the total letters presented

Psychiatric Conditions

OSPAN performance tends to be impaired in patients with the following psychiatric conditions:

• Bipolar Disorder
• Attention Deficit Hyperactivity Disorder (ADHD)
• Schizophrenia
• Major Depressive Disorder
• Anxiety Disorders
• Obsessive Compulsive Disorder