Cecchetto, S., & Lawson, R.

For vision, mirror-reflectional symmetry is usually easier to detect when it occurs within 1 object than when it occurs across 2 objects. The opposite pattern has been found for a different regularity, repetition. We investigated whether these results generalize to our sense of active touch (haptics). This was done to examine whether the interaction observed in vision results from intrinsic properties of the environment, or whether it is a consequence of how that environment is perceived and explored. In 4 regularity detection experiments, we haptically presented novel, planar shapes and then visually presented images of the same shapes. In addition to modality (haptics, vision), we varied regularity-type (symmetry, repetition), objectness (1, 2) and alignment of the axis of regularity with respect to the body midline (aligned, across). For both modalities, performance was better overall for symmetry than repetition. For vision, we replicated the previously reported regularity-type by objectness interaction for both stereoscopic and pictorial presentation, and for slanted and frontoparallel views. In contrast, for haptics, there was a 1-object advantage for repetition, as well as for symmetry when stimuli were explored with 1 hand, and no effect of objectness was found for 2-handed exploration. These results suggest that regularity is perceived differently in vision and in haptics, such that regularity detection does not just reflect modality-invariant, physical properties of our environment.

Journal of Experimental Psychology: Human Perception and Performance (2017), 43, 103-125.