Robots and Reflexes: Analyzing the Stroop Effect and Impulsiveness in Human-Robot Interaction

Socially Assistive Robots (SARs) are increasingly employed in clinical environments to support cognitive and rehabilitative tasks through social interaction. This study explores the integration of SARs into neuropsychological assessment by implementing and comparing two versions of the Stroop Color and Word Test: a standard PC-based version and a novel robot-mediated version involving a handover task with a robotic manipulator. Thirty-one participants completed both conditions in a within-subject design, under congruent and incongruent stimulus settings. Our findings confirm the expected Stroop effect in the PC-based modality, with increased reaction times (RTs) in the incongruent condition. In contrast, the robot-based implementation revealed an inverted trend, where incongruent trials resulted in faster RTs—likely due to temporal synchronization between user movements and robotic motion, indicating a strong sensorimotor coupling effect. Analysis of user impulsiveness, measured via the Barratt Impulsiveness Scale, showed a significant impact on task performance in the PC-based version, but not in the robot-mediated version, suggesting that interaction with the robot may attenuate impulsivity-driven variability. These results underline the importance of adaptive robot behavior in eliciting meaningful cognitive responses and offer valuable insights for designing personalized, interaction-aware SARs.