Phasic Alertness and Residual Switch Costs in Task Switching

• Published in: Journal of experimental psychology. Human perception and performance 2017-02, Vol.43 (2), p.317-327
• Main Author: Schneider, Darryl W
• Format: Article
• Language: English
• Subjects: Adult; Alertness; Awareness; Cognition; Cognition & reasoning; Cognitive ability; Cognitive Control; Cues; Dual Task Performance; Executive Function - physiology; Experimental psychology; Human; Humans; Manipulation; Pattern Recognition, Visual - physiology; Psychomotor Performance - physiology; Stimulus; Task performance; Task Switching; Young Adult
• ISSN: 0096-1523; 1939-1277
• DOI: 10.1037/xhp0000318

Residual switch costs are deficits in task-switching performance that occur despite considerable time to prepare for a task switch. In the present study, the author investigated whether increased phasic alertness modulates residual switch costs. In 2 experiments involving the task-cuing procedure, subjects performed numerical categorization tasks on target digits, with and without an alerting stimulus presented shortly before the target (alert and no-alert trials, respectively). Switch costs were obtained that decreased with a longer cue-target interval, indicating subjects engaged in preparation, but large residual switch costs remained. Alerting effects were obtained in the form of faster overall performance on alert than on no-alert trials, indicating the alerting stimuli increased phasic alertness. Critically, residual switch costs were similar on alert and no-alert trials in both experiments, unaffected by manipulations of alert type, alert availability, and alert-target interval. Implications of the results for understanding the relationship between phasic alertness and cognitive control in task switching are discussed. Public Significance Statement People are slower and more error-prone at switching than repeating tasks, even when they are provided with time to prepare for a task switch. In the present study, the author investigated whether the cost of task switching is influenced by temporary changes in alertness. In 2 experiments, college students completed numerical categorization tasks faster when alerting stimuli were presented than when they were not, indicating that simple alerts can improve general task performance. However, large costs of switching tasks still occurred and were unaffected by the meaning, availability, and timing of the alerts. These findings suggest that preparation and control associated with switching tasks are not influenced by a person's state of alertness, clarifying the role of attention in task switching.