Set- and Element-Level Stimulus-Response Compatibility Effects for Different Manual Response Sets

In a previous study of two-choice reactions, pairings of spatial stimuli with bimanual presses made on a keyboard and verbal stimuli with unimanual aimed movements made on a display screen showed higher set-level compatibility than the opposite pairings; element-level compatibility (i.e., mapping) effects were also larger for the conditions with high set-level compatibility than for those whose set-level compatibility was low. In the 4 experiments described here, the relevant factors were isolated, allowing the determinants of those compatibility differences to be evaluated in more detail. Forty-eight students participated in Experiment 1, and 24 each in Experiments 2, 3, and 4. The primary determinant of the set-level compatibility variation was whether the response alternatives involved 1 or 2 effectors, but the differences in element-level compatibility effects were determined primarily by the distinction between responding on the screen as opposed to on the keyboard. Implications for models of stimulus-response compatibility are examined.