Costs of a predictable switch between simple cognitive tasks following severe closed-head injury.

Abstract

The authors used a predictable, externally cued task-switching paradigm to investigate executive control in a severe closed-head injury (CHI) population. Eighteen individuals with severe CHI and 18 controls switched between classifying whether a digit was odd or even and whether a letter was a consonant or vowel on every 4th trial. The target stimuli appeared in a circle divided into 8 equivalent parts. Presentation of the stimuli rotated clockwise. Participants performed the switching task at both a short (200 ms) and a long (1,000 ms) preparatory interval. Although the participants with CHI exhibited slower response times and greater switch costs, similar to controls, additional preparatory time reduced the switch costs, and the switch costs were limited to the 1st trial in the run. These findings indicate that participants with severe CHI were able to take advantage of time to prepare for the task switch, and the executive control processes involved in the switch costs were completed before the 1st trial of the run ended. Keywordsclosed-head injury; traumatic brain injury; executive functions; task switching; set shifting Multiple-task performance is theorized to involve executive control processes, which supervise the selection, initiation, execution, and termination of each task (e.g., Baddeley, 1986;Logan, 1985;Norman & Shallice, 1986;Rubinstein, Meyer, & Evans, 2001). In the closed-head injury (CHI) literature, much of the research that has addressed multiple-task performance has focused on simultaneous multitask performance rather than successive or rapid alternation multiple-task performance. These studies generally indicate that persons who suffer severe CHI (i.e., brain injury resulting from a rapid acceleration of the head followed by a rapid deceleration without an object penetrating the brain) experience greater difficulty than controls in coordinating and monitoring simultaneous task performances (e.g., Brouwer, Verzendaal, van der

Cross-modal transfer after auditory task-switching training

“…Performance costs (i.e., prolonged response times) were observed both when the relevant feature had switched within the same dimension from one trial to the next (e.g., from male to female or from right to left), and when the relevant dimension had switched from gender to voice or vice versa, although the feature-switch effect was much larger than the dimensionswitch effect (Lawo et al, 2014). While such studies suggest the occurrence of additional costs when switching attention between auditory stimulus features or dimensions (i.e., attention switching), they leave open the question of whether the switching between different task sets (task switching) presented to the two ears would lead to the same switch and mixing costs in the auditory domain that were reported for visually presented tasks (Rogers & Monsell, 1995), and whether these costs can also be reduced as a result of training.…”

“…In the present study, a task-switching paradigm in which participants are instructed to perform two tasks sequentially is utilized to investigate the transfer of a cognitive training that addresses set-shifting abilities. In a typical task-switching situation (Jersild, 1927;Rogers & Monsell, 1995), participants have to switch between two tasks, such as between adding and subtracting numbers or between categorizing letters (e.g., vowel vs. consonant) and digits (e.g., even vs. odd). It has been found that performance drops (i.e., longer response times and lower accuracy) after a task switch (switch trials) as compared to trials on which the task from the previous trial is repeated (repeat trials).…”

“…It has been found that performance drops (i.e., longer response times and lower accuracy) after a task switch (switch trials) as compared to trials on which the task from the previous trial is repeated (repeat trials). These switch costs are assumed to reflect the Bspecific^demands involved in shifting between two particular mental task sets (i.e., low costs reflecting high cognitive flexibility; Mayr & Kliegl, 2003;Rogers & Monsell, 1995;Strobach, Liepelt, Schubert, & Kiesel, 2012), which is presumably driven by both the activation of the relevant task set and the inhibition of the irrelevant task set(s) (Monsell, 2003). 1 In addition, there is usually also a performance decrement in mixed-task blocks (in which participants have to switch between tasks based on a particular trial protocol) as compared to single-task blocks (e.g., longer response times).…”

Behavioral and electrophysiological correlates of cognitive control in ex-obese adults

“…Consequently, the attenuated amplitude of the switch-positivity in the patients' group suggests the presence of altered proactive/anticipatory control processes. These control processes refer to the endogenous mechanisms of task-reconfiguration conceptualized by Rogers and Monsell (1995), which include shifting attention between stimulus attributes or features, retrieving task goals and rules, updating (or deleting) them in working memory. An alteration of these mechanisms might explain the RT slowing in switch trials.…”

Puppets, robots, critics, and actors within a taxonomy of attention for developmental disorders

“…Adjustment enables set shift to redirect attention. The shift cognitive phenotype may be measured by shifting attention in response to an endogenous cue (Schmitter-Edgecombe & Langill, 2006). …”