Cognitive Control and Task Switching


On Friday, Feb. 17 in Goodpaster Hall 195, the Cross-Disciplinary Minor in the Neurosciences hosted a lecture called “Event-related Brain Potential Correlates in Cognitive Control” by Dr. Paul Kieffaber, an Assistant Professor in the Department of Psychology at the College of William and Mary.

The crowded lecture brought in students and professors of psychology and neuroscience as Kieffaber outlined his research of both fields, which primarily focuses on the psychophysiology of attention and cognitive control.  Though cognitive neuroscience overlaps into both biology and psychology, he explained his research as focusing more on the psychological side, aiming to study the behaviors that define the cognitive process and if those behaviors are reflected in brain activity.

Kieffaber explained cognitive control like “a physical posture.” The posturing of perceptual, cognitive, and motor processes helps us to orient attention to relevant input, activate appropriate output and specific configuration of biases, which is a “task-set.”  A “task-set” is defined as an effective intention to perform a task which is done by configuring one’s mental state to be in accord with the task-specific operations which define the to-be-performed task when several task responses are possible.

To measure peoples’ abilities to perform executive functions in task-sets, Kieffaber carried out experiments that involved task-set switching procedures.  The experiments included two groups of people in which the first did four addition problems then four subtraction problems, and in which the second group did both math problems that alternated from subtraction to addition in between each problem.

The results showed that the first group, which completed the two different sets of problems without alternating, was more successful.  “This is why assembly lines are more efficient,” explained Kieffaber, because people are more efficient when they focus on one task each. “The more switch costs, the less cognitive control of task-switching,” he continued.  “The less the amount of task switches, the more preparatory time for the brain to perform the task successfully.”

Further experiments carried out to research this topic had participants sit in front of a computer screen, see a prompt, judge whether the shapes presented are squares or circles, and then judge the shape’s size.  Scientists focus on the exact moment of the attention switch, or the moment when they are asked to perform a different task in regard to the shapes presented.

These studies agreed with the first study, showing how people take significantly longer to perform the switch task than a task that repeats.  Also, the study shows that there is significantly more activity going on in the brain during the switch, mainly in the posterior parietal network.  To receive these results, psychologists use an electroencephalograph (EEG) to measure the brain activity going on during the experiments.

This research is often used, particularly in Kieffaber’s research that links these problems in cognitive control to psychological disorders such as autism, bipolar disorder, brain injury, bulimia, schizophrenia, ADHD, Tourette’s syndrome, and other disorders. “Just about every mental disorder has some type of cognitive control disorder,” Kieffaber explained.

In further research, Kiefabber applied these findings to participants with schizophrenia.  The experiment included 30 schizophrenic subjects and 27 healthy control subjects, and all participated in the same procedure as above, in which they had to judge shapes within different task-sets.  The results concurred, revealing that schizophrenic patients had overall longer reaction times.  Conclusions from these findings include that the attention-switching component of cognitive control is preserved in schizophrenia. Kieffaber and his colleagues are currently carrying out further research in regards to the topic.

Sophomore Johanna Laue liked the lecture and found the topic interesting.  “I liked how it was easy to understand no matter your background in neuroscience,” she said.  “It was intriguing in that his studies related a better understanding to mental illness.”