Response mapping interacts with perceptual thresholds and stimulus processing speed.
Shalev N., Humphreys G., Demeyere N.
Traditionally, response selection is considered to reflect a separate stage of processing to visual perception. An alternative view proposes action and perception to be closely linked; however the processing stage where any cross-modal interaction would then occur remains unclear. In this study, we investigated the influence of response-mapping on a simple classification task. We presented an array of eight frames arranged in a square around a fixation point, followed by a brief presentation of an arrow in one of them (varying SOAs of 10,30,50,80 and 100ms masked). The arrow could appear in a congruent, incongruent or a neutral location with respect to its direction. Participants indicated the direction of the arrow using a response-box organized in a corresponding configuration: eight response-buttons, arranged in a square; an arrow appeared on each button. In Exp 1, the directions of the buttons matched their locations (e.g., arrow pointing right appearing on the right side); In Exp 2, the arrows and the locations were mismatched (arrow appearing on the left side, pointing right). Subsequently we manipulated the response-mapping between the locations and directions of the arrows. We changed the task to respond to locations instead of direction, in a single (Exp 3) and a dual task (Exp 5); and replicated our original experiment with different exposure times (Exp 4). In our first experiment, we observed a robust congruency effect on accuracy for arrows appearing in their matching locations. Crucially, in our following experiments, we managed to invert and manipulate this effect by changing the motor-response mapping. Using mathematical modelling according to the Theory of Visual Attention, we demonstrate that motor-mapping modulates two low-level processes independently: perceptual threshold and stimulus processing speed. We discuss the implications of multi-modal integration within a general framework of attention as a proactive cognitive function, which predicts and formulates visual percepts. Meeting abstract presented at VSS 2015.