Crossmodal discrimination of object shape

Anna Seemüller, Katja Fiehler, Frank Rösler
Poster
Last modified: 2008-05-09

Abstract


Object shape discrimination is dependent on information from visual and somatosensory (tactile and kinaesthetic) modalities. Whereas subjects show precise discrimination for geometric shapes presented visually or through active hand movements, the perception of shape through passively guided hand movements is still to be examined. Here, we investigated unimodal (visual – visual, kinaesthetic – kinaesthetic) and crossmodal (visual – kinaesthetic, kinaesthetic – visual) discrimination for different angles. In a delayed matching-to-sample task, participants compared two movement trajectories either presented visually as moving light point on a screen or kinaesthetically as passively guided hand movement via a manipulandum. Accuracy was measured by an adaptive psychophysical procedure. Shape discrimination was more accurate in the kinaesthetic condition compared to crossmodal conditions and did not significantly differ from the visual condition. Therefore, the kinaesthetic sense seems to be acute enough for sensorimotor control. Overall, crossmodal discrimination was less accurate than unimodal discrimination, independent of the presented angle, indicating an information loss due to the required transfer process.

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