In spatial compatibility tasks, performance is better when participants respond to stimuli presented on the right side by pressing the right key than by pressing the left key, and vice versa for left-sided stimuli. This phenomenon is referred to as the spatial stimulus-response compatibility (SRC) effect. When valence judgment tasks are used, in which participants respond to positive stimuli in a spatially compatible manner and to negative stimuli in an incompatible manner, or with the mappings switched (Affective Spatial Compatibility Task), a different pattern of results emerges. Specifically, performance is better with a positive-compatible and negative-incompatible stimulus-response mapping than vice versa, resulting in a reversed SRC effect for negative stimuli. This valence-by-mapping (VM) interaction has been attributed to approach/avoidance tendencies or differences in the ease of task-set selection (i.e., the specific stimulus-response mapping).
In the present study, we expanded on these findings by comparing the effect induced by flower and spider images from previous studies with those of novel stimulus sets and judgment tasks: symmetric vs. asymmetric letter strings in Experiment 1, and congruent vs. incongruent Stroop stimuli in Experiment 2. We found a more pronounced VM interaction for both letter-string and Stroop stimuli, despite their relatively low valence ratings.
Taken together, our results challenge the approach/avoidance account and instead suggest more general semantic comparison processes underlying the VM interaction.