Set and element-level compatibility of spatial and location-word stimuli paired to eye-movement, vocal, and keypress response modalities
Set-level and element-level compatibility are two ways to differentiate between different components of stimulus-response compatibility. Element-level compatibility (the difference between incongruent and congruent mappings) has been shown in prior studies to be an increasing function of set-level compatibility (differences between pairings of stimulus and response ensembles). When manual and vocal response sets are paired with spatial (physical location) stimuli and verbal (location-word stimuli), the difference between the incongruent and congruent mappings is larger for the spatial-manual and verbal-vocal conditions than for the alternative pairings of lower set-level compatibility. The common use of eye tracking technology in psychological experiments necessitates investigating the set-level compatibility of the oculomotor system through use of various stimulus sets. Saccadic eye movements are known to yield element-level compatibility effects (longer response times for antisaccades in the opposite direction of the stimulus than for prosaccades in the direction of the stimulus). Although the tendency to make a prosaccade is often described as highly automatic, no attempt has been made to evaluate the overall set-level compatibility of eye-movement responses in comparison to vocal location-naming responses or manual responses. Consequently, I conducted two experiments in which eye-movement responses were compared to those two response modalities: vocal responses (Experiment 1) and keypress responses (Experiment 2). Visual stimuli were varied through use of onsets of squares in left and right spatial locations (spatial codes) or centrally presented words ‘left’ and ‘right’ (verbal codes). The relative set-level compatibility of the two response sets was evaluated by comparing performance with a congruent mapping of spatial and verbal location stimuli; the element-level compatibility effects were evaluated by comparing the differences in performance for incongruent and congruent mappings. The results provide evidence of set-level compatibility differences, with eye movements not only being more compatible than vocal responses with spatial stimuli than verbal stimuli, but also relatively more compatible than keypresses. This result pattern implies that eye movements are more extreme than keypress responses on the spatial end of a response spectrum, compared to vocal responses. Despite this difference in set-level compatibility, in Experiment 1 the element-level mapping effect for sets with high set-level compatibility (including eye-movement responses to spatial) was no larger than that for sets with low set-level compatibility (including eye-movement responses to verbal stimuli). A positive relation between relative set-level compatibility and the element-level mapping effect was found in Experiment 2 when eye movements were compared to keypresses, but this was due mainly to the keypress responses. That incompatible, antisaccade eye-movement responses are not slowed by higher set-level compatibility is counter to the view that set-level compatibility increases activation of the spatially congruent response regardless of the stimulus-response mappings. Alternative possible explanations for the influence of set-level compatibility on eye-movement responses are discussed.
Proctor, Purdue University.
Behavioral psychology|Behavioral Sciences|Psychology
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