- Stressful life situations can impair or facilitate various cognitive functions. In the present study, the effect of examination stress on students was examined using two executive function tasks, task-switching and the Stroop task, in a between-subject crossover design. Students showed increased anxiety in the 2 week period prior to exams compared to the beginning of the semester, manifested as higher scores on the Spielberger State-Trait Anxiety Scale and a shift to more sympathetic activation when heart rate variability was assessed. During the stressful period, the switching cost was reduced on a spatial task- switching paradigm and reaction times in the Stroop task were faster. This is the first study to show stress-induced facilitation of performance on these executive function tasks.