Cardiovascular response to Stroop: effect of verbal response and task difficulty

Area of Science:

• Psychophysiology
• Cardiovascular Physiology
• Cognitive Neuroscience

Background:

• The Stroop task is a widely used cognitive test to assess selective attention and executive function.
• Previous research indicates that the Stroop task elicits physiological responses, but the specific impact of verbal response and task difficulty on these responses requires further investigation.

Purpose of the Study:

• To investigate the influence of verbal response and task difficulty on cardiovascular and catecholamine responses during the Stroop task.
• To compare physiological reactions across different versions of the Stroop task, varying in cognitive conflict and response requirements.

Main Methods:

• 13 male participants completed three 5-minute versions of the Stroop task.
• Measurements included heart rate, mean arterial blood pressure, forearm blood flow (FBF), and plasma catecholamines (epinephrine).
• Subjective ratings of task difficulty and concentration were also collected.

Main Results:

• Heart rate, epinephrine, and FBF were significantly higher during the color-word conflict Stroop task compared to a non-verbal version.
• Mean arterial pressure was significantly elevated during the conflict task compared to both a monochrome word reading task and the non-verbal version.
• Subjective difficulty and concentration ratings were lower for the monochrome word reading task.

Conclusions:

• The traditional Stroop task induces significant cardiovascular, forearm blood flow, and epinephrine reactivity.
• This physiological reactivity is attenuated by reducing cognitive conflict (monochrome words) and virtually abolished when verbal responding is removed.