Self-Ordered Pointing Task (SOPT)

Background

The Self-Ordered Pointing Task (SOPT) is a widely used neuropsychological assessment developed by M. Petrides and B. Milner in 1982. It primarily measures executive working memory, specifically the ability to initiate, monitor, and organize internal sequences of responses which are heavily associated with the prefrontal cortex.

During a routine SOPT procedure, participants are shown the same array of items on several pages but on each page the items change positions. On each page, they are asked to pick out a new (not previously selected) item. They must do this from memory, ensuring they never point to an item they have already selected in a previous turn. Because the item positions change, participants cannot rely on spatial memory alone. They must generate an internal strategy (e.g., scanning the page in a specific order) while actively updating a mental record of which items have already been selected.

The Millisecond default SOPT implementation uses 'representational drawings' as stimuli, which are clear, easily recognizable illustrations of everyday objects such as a tree, a shoe, or an airplane. Because the stimuli are recognizable objects (e.g., "dog," "car"), participants can use an internal verbal narrative to help keep track of their choices. They might mentally repeat, "I already picked the car and the tree, so next I will pick the shoe". Generally, SOPTS with representational drawings are considered significantly easier than SOPTS using abstract imagery because the brain is not burdened with memorizing the visual characteristics of the shapes themselves.

Researchers often use both the representational and abstract SOPTS versions together. Comparing the scores allows clinicians to determine if a patient's executive dysfunction is specifically tied to visual-spatial memory (abstract shapes) or verbal working memory (representational objects).

Task Procedure

After the instructions that include two demo trials, participants work on 4 blocks, with each block testing a different item set size N (6,8,10 or 12 items) with three trials per set size. The blocks are run in ascending order, starting with N=6 and ending with N=12 items. Each trial presents a participant with N pages that show an array of the N objects. On each page, the N items are presented in a random arrangement and participants need to select a new item (not previously selected ones). The Millisecond SOPT has built-in functionality that checks several different rules such as the position rule ('always click on the same matrix position') and alphabet rule ('select by alphabet position'). If the responses are evaluated to follow such a rule, a response reminder is presented to the participant. An error is logged any time participants select an item that they had previously selected in the same trial.

What it Measures

The Self-Ordered Pointing Task (SOPT) measures executive functioning, particularly updating executive working memory.

Psychological domains

• Executive Control: Collection of "top-down" mental processes used to manage and regulate thoughts and actions.
• Response Planning and Sequencing: Formulating an intentional plan to choose items methodically rather than reacting randomly.
• Interference Control: Previous selections need to be ignored.
• Working Memory: Ability to hold information in the mind, manipulate it, and continuously monitor their ongoing choices.
• Sustained Attention: Maintaining focus over a repetitive series of trials without 'drifting'.

Main Performance Metrics

• Total Error Score: Number of selection errors (selecting a previously selected item) made across all trials; main global SOPT measure
• Set size Error Score: Number of selection errors per trial and set size

Psychiatric Conditions

The SOPT is frequently used to assess prefrontal cortex damage, normal aging, and neurodegenerative disorders. Performance tends to be impacted in the following patient groups:

• Frontal Lobe Lesions
• Parkinson’s Disease (PD)
• Alzheimer’s Disease (AD)
• Mild Cognitive Impairment (MCI)
• Schizophrenia
• Major Depressive Disorder (MDD)
• Attention-Deficit/Hyperactivity Disorder (ADHD)

References

Search Google Scholar for peer-reviewed, published research using the Inquisit Self-Ordered Pointing Task (SOPT).

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Petrides, M., & Milner, B. (1982). Deficits on subject-ordered tasks after frontal- and temporal-lobe lesions in man. Neuropsychologia, 20, 249–262.

Shimamura, A. P. & Jurica, P. J. (1994). Memory Interference Effects and Aging: Findings From a Test of Frontal Lobe Function, 8, 408-412.

West, R., Ergis, A. M., Winocur, G., Saint-Cyr, J. (1998). The contribution of impaired working memory monitoring to performance of the self-ordered pointing task in normal aging and Parkinson's disease. Neuropsychology, 12, 546-554.

Ross, T. P., Hanouskova, E., Giarla, K., Calhoun, E., Tucker. M. (2007). The reliability and validity of the self-ordered pointing task. Archives of Clinical Neuropsychology, 22, 449-458.

Gillett, R. (2007). Assessment of working memory performance in self-ordered selection tests. Cortex, 43, 1047-1056.