Tactile Stimulus–Response Compatibility Effects: Differentiating Methodology and Frames of Reference

Abstract Tactile stimulus–response (S-R) compatibility effects have been explained in 3 different frame of reference accounts: internal, external, or remapping. However, it remains unclear which frame of reference contributes to these effects. The present study used various S-R compatibility paradigms to investigate the reference frames used to encode tactile stimuli and facilitate response selection. Experiment 1 validated a novel apparatus by obtaining a standard S-R compatibility effect in an uncrossed-hands condition (hands in their corresponding lateral spatial location) and demonstrating a reversed S-R compatibility effect in a crossed-hands condition (hands in their noncorresponding spatial location). Experiment 2 examined whether stimulus frequency carried spatial associations by having participants respond to low- and high-frequency vibrotactile stimuli with left or right responses. No spatial association was found, confirming that frequency served as a nonspatial, task-relevant dimension suitable for use in a tactile Simon task. Experiment 3 compared the role of internal and external frames in a tactile Simon task. In the tactile Simon task, participants responded to stimulus frequency with left or right responses in both uncrossed- and crossed-hands conditions. A typical Simon effect emerged in the uncrossed-hands condition but disappeared when hands were crossed, suggesting that effector identity influenced performance. These findings indicate that both internal and external reference frames contribute to the tactile Simon effect. Overall, the results demonstrate that multiple reference frames can be used to process vibrotactile information for response selection and offer important implications for the design of vibrotactile warnings in human–automation systems.