16:00 - 17:00
1.702 - Department of Psychology
Psychology, Department of
Objects play an important theoretical role within many fields in perception and cognition. However, researchers have largely ignored the difficult task of defining what we mean by an object. This is the case even for visual stimuli (Feldman, 2003), whilst this issue has barely been considered for touch. Given the limited ability of our sense of touch to explore multiple objects simultaneously, and to perceive scenes, then it might be that objectness is relatively unimportant for touch.
Also, our sense of touch could perhaps rely on vision to specify objects. However, the results of our studies investigating regularity detection suggest that defining what is an object does play an important role in processing by touch as well as by vision. We investigated whether symmetry signals the presence of one object and repetition signals the presence of multiple, similarly-shaped objects, for stimuli presented to touch alone or to vision alone. Multiple cues seem to be combined to define objects by touch, with some cues (e.g., proximity and contour polarity - concavities and convexities along a contour) also being used by vision, but other cues (e.g., whether stimulus exploration involves one rather than two hands) being modality-specific.
Thus the nature of an object appears to differ for vision and touch. This conclusion means that objects cannot be defined objectively by properties of the external world. Instead, objects seem to be specified relative to the modality-specific system used to process them.