Symmetry Span Task (SYMMSPAN)

Background

The Automated Symmetry Span Task (SYMMSPAN) is a standardized, computerized measure of visuo-spatial working memory and was introduced by Randy Engle and colleagues in 2005, together with other span tasks such as the Automated Operation Span (OSPAN) as well as the Automated Reading Span (RSPAN) task. All span task require people to simultaneously process new information and store specific items for later recall. But whereas both OSPAN and RSPAN target verbal working memory in the form of recalling letter sequences under the influence of mathematical (OSPAN) or semantic processing interferences (RSPAN), SYMMSPAN assesses visuo-spatial working memory. Specifically, the SYMMSPAN requires participants to recall the highlighted squares in a 4x4 matrix while simultaneously processing the symmetry of images.

Task Procedure

The SYMMSPAN combines a square-span task (participants recall a sequence of highlighted matrix squares) with a simple visual evaluation task (participants judge whether images are symmetric or not). Participants first solve a symmetry problem before they receive a matrix square position to memorize. This sequence is repeated until all square positions of the current span length have been presented at which point the square recall screen is presented.

Square Span Task

In the square-span task, participants are shown, one at a time, a series of highlighted squares randomly drawn from the positions of a 4x4 matrix, followed by an empty 4x4 recall matrix. They must the recall the sequence by clicking each matrix square in the order they were highlighted. Feedback is provided indicating the number of positions correctly recalled, with positions recalled in the wrong order treated as incorrect.

Symmetry Task

In the symmetry task, participants are shown black and white pixelated images and are instructed to click the mouse button once they've determined whether the image is symmetrical or not. A new screen appears with the question "Is this symmetrical?" and two response buttons labeled "YES" and "NO", which they must click to indicate whether they agree that the image was symmetrical (Yes) or not (No). 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.

While the main measure taken by the test is recall performance, participants are instructed to work at a high performance level (at least 85% correct) on the symmetry evaluation task.

What it Measures

The SYMMSPAN is a measure of (visuo-spatial) 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

• SYMMSPAN Score: Total number of correct square positions recalled in the correct order in perfectly recalled sets
• Partial-credit unit (PCU): Total number of square positions recalled relative to the total square positions presented

Psychiatric Conditions

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

• Attention Deficit Hyperactivity Disorder (ADHD)
• Schizophrenia
• Multiple Sclerosis
• Alzheimer’s Disease (AD)
• Post-Traumatic Stress Disorder (PTSD)