Action relations affect affordance selection: Evidence from visuomotor responses to paired objects

摘要

The implied actions between objects affect object perception by grouping these objects into perceptual units (e.g. Riddoch et al., 2003). The present study extended this line of investigation and examined the influence of implied actions on the automatic sensorimotor response to each involved object. Similar to studies on affordance-based effects of single objects (e.g. Philips & Ward, 2002), we presented pairs of task-irrelevant objects which are typically used together (e.g. a jug and a cup). Then imperative target was added on the screen centre. In response to the shape of the target (square/triangle), the participants made speeded left/right responses. Thus the responses were aligned with objects positions on the screen. The implied actions between objects were manipulated by varying the orientation of one of the objects, leaving the co-location of objects correct or incorrect in terms of the afforded actions. When the co-locations of objects were correct, responses compatible with active objects (e.g. jug) were quicker than those compatible with passive objects (e.g. cup). The correct co-location slowed down responses compatible with the passive objects compared to when the co-location was incorrect. Little evidence was found for the effect of response modality (between-hand in Experiment 1 and 2, within-hand in Experiment 3 and reaching-and-grasping in Experiment 4), suggesting that visuomotor responses to paired objects were less dependent on activating the exact motor program of the afforded action than on the congruency between spatial codes of the responses and the stimuli. Our results suggested that the active objects in action-related object pairs dominate the visuomotor responses to the visual scene, and inhibit the visuomotor responses to the passive objects. These results underline the contextual influence on the selection of affordance, suggesting that action relation between objects might be a critical factor for determining the visuomotor representation of objects in visual scenes.