A visual-haptic Necker cube reveals temporal constraints on intersensory merging during perceptual exploration.
When viewing a three-dimensional Necker cube with one eye, participants can experience illusory reversals even while they feel the cube with their hands. This surprising property of the visual-haptic Necker cube affords a unique opportunity to investigate temporal constraints on interactions between vision and touch during extended observation of a three-dimensional object. Our observers reported reversals while they viewed the cube and, at the same time, they either held it with two-finger grips, felt it with while their hands remained stationary, or actively explored it by moving one hand. Consistent with a multisensory approach to three-dimensional form perception, touch had a clear effect on both the number and the duration of illusory percepts. Additionally, when observers alternated between stationary and moving periods during exploration, transitions from stationary to moving-hand haptics played a crucial role in inhibiting illusory reversals. A temporal analysis of the probability of first reversals occurring after different types of motor transition revealed a "vetoing window" initiating approximately 2s after the transition and lasting at least another 1-2s. Implications for multisensory processes during exploration are discussed.
Bruno
Nicola
N
Dipartimento di Psicologia and BRAIN Center for Neuroscience, Università di Trieste, via S. Anastasio 12, 34134 Trieste, Italy. nick@psico.univ.trieste.it
Jacomuzzi
Alessandra
A
Bertamini
Marco
M
Meyer
Georg
G
D005556:Form Perception / Q000502:physiology*; D006801:Humans; D009068:Movement; D009903:Optical Illusions / Q000502:physiology*; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010775:Photic Stimulation; D011336:Probability; D011597:Psychomotor Performance / Q000502:physiology; D011601:Psychophysics; D011930:Reaction Time; D013028:Space Perception / Q000502:physiology*; D013997:Time Factors; D014110:Touch / Q000502:physiology*