Effects of caffeine, practice, and mode of presentation on Stroop task performance

Area of Science:

• Cognitive Psychology
• Neuroscience
• Pharmacology

Background:

• The Stroop task is a common measure of executive function and cognitive control.
• Caffeine is a widely consumed psychoactive substance with known effects on alertness and attention.
• Investigating caffeine's impact on cognitive tasks like the Stroop is crucial for understanding its real-world effects.

Purpose of the Study:

• To examine the effects of two caffeine doses (125 mg and 250 mg) versus a placebo on Stroop task performance.
• To compare performance on both classic colour-word and numerical versions of the Stroop task.
• To evaluate the influence of different presentation methods (computerised vs. card) on Stroop task outcomes.

Main Methods:

• Participants completed the Stroop task under conditions with caffeine (125 mg, 250 mg) or placebo.
• Both a classic colour-word version and a numerical version of the Stroop task were employed.
• The task was administered using both computerised and traditional card-based formats.

Main Results:

• Caffeine administration did not produce significant changes in Stroop task performance across either task version or presentation format.
• Significant practice effects were observed in the within-subjects design using the card version of the task.
• Performance differences were noted between the card and computerised versions of the Stroop task.

Conclusions:

• The tested doses of caffeine do not appear to significantly alter performance on the Stroop task.
• Practice effects in within-subject designs can potentially confound the detection of subtle drug effects on cognition.
• The computerised Stroop task may not be a direct equivalent to the traditional card version, suggesting methodological considerations are important.