Is Handedness Information Critical for Discriminating Figure Pairs?

Fumio Kanbe

doi:10.3390/sym11050624

Abstract

Mirror-reflected or axisymmetric (Ax) pairs of figures are known to be difficult to discriminate. If non-identical pairs of figures with specific feature values impede discrimination to the same extent as the discrimination of Ax pairs, the feature values concerned would be expected to cause discrimination difficulty and may be critical for figure recognition in general. In the present study, we examined whether handedness information (i.e., the left or right side of a disoriented figure) is critical for the discrimination of figure pairs with pairs of complex figures (Experiment 1) and simpler figures (Experiment 2). Participants performed a task requiring discrimination of whether the figures in a pair had the same shape regardless of orientation. Three basic pair types were prepared: identically shaped pairs, Ax pairs, and non-identical, non-axisymmetric (Nd) pairs. Non-axisymmetric pairs were further classified into same-handedness pairs and opposite-handedness pairs. The results revealed that discrimination latencies were longer for Ax pairs than for both same-handedness pairs and opposite-handedness pairs. These findings suggest that handedness information is not a critical feature in figure recognition.

Highlights

Shepard and Metzler [1] reported that latencies for making same/different decisions about simultaneously presented pairs of rotated but identically shaped objects increased linearly with the angular distance between the two objects in three-dimensional space within the range of 0◦ to 180◦ .Because this linearity of latencies was evident across stimuli and participants, the researchers assumed that the process of making identity decisions about the rotated objects involved “mental rotation in three-dimensional space” (p. 703)
Nd op pairs the hypothesis that the lack of sensitivity to opposite handedness causes difficulty in discriminating didpairs
Nd op pairs participants were not sensitive to handedness information as a whole, and that handedness may not be indicated that participants a critical superficial feature. were not sensitive to handedness information as a whole, and that handedness may not be a critical superficial feature

Summary

Introduction

Shepard and Metzler [1] reported that latencies for making same/different decisions about simultaneously presented pairs of rotated but identically shaped objects increased linearly with the angular distance between the two objects in three-dimensional space within the range of 0◦ to 180◦ .Because this linearity of latencies was evident across stimuli and participants, the researchers assumed that the process of making identity decisions about the rotated objects involved “mental rotation in three-dimensional space” (p. 703). Shepard and Metzler [1] reported that latencies for making same/different decisions about simultaneously presented pairs of rotated but identically shaped objects increased linearly with the angular distance between the two objects in three-dimensional space within the range of 0◦ to 180◦ Because this linearity of latencies was evident across stimuli and participants, the researchers assumed that the process of making identity decisions about the rotated objects involved “mental rotation in three-dimensional space” For normal versus mirror-reflected decisions about memorized letter-like symbols [6], memorized Shepard’s blocks [7], and memorized random polygons [8], slopes are reported to be in the rage of 1 ms/◦ and 5 ms/◦ These results indicate that mental rotation is involved in the recognition of both 3D and 2D stimuli. Cohen and Symmetry 2019, 11, 624; doi:10.3390/sym11050624 www.mdpi.com/journal/symmetry

Methods

Results

Conclusion