ECVP 2003 Abstract
doi:10.1068/v031129

Cite as:
Wilson S, Goddard P A, Hamilton G, 2003, "A two-tiered hierarchy for perceptual change" Perception 32 ECVP Abstract Supplement

A two-tiered hierarchy for perceptual change

S Wilson, P A Goddard, G Hamilton

The Necker cube (NC) figure appears to switch between two 3-D perceptual alternatives, 'cube up' (CU) and 'cube down' (CD). However, experienced observers not only report CU and CD but also a myriad of 2-D percepts. Four experienced observers recorded perceptual changes that occurred during observation periods lasting 5 min. In one period they recorded when the CU percept began and finished, thereby giving the number and duration of CU percepts; this was repeated for CD and 2-D percepts. The sum of the durations for the percept of CU was about the same as that for CD; taken together CU and CD percepts accounted for between a third and a half of an observation period. The sum of the 2-D percepts accounted for between a half and two-thirds of an observation period. The distributions of CU and CD percept durations were similar and were modelled adequately by gamma distributions. These percepts tended to be brief (about 1 s) compared to the far more stable, and normally distributed, 2-D percepts. The difference between the characteristics of CU/CD and 2-D percepts is consistent with a system that operates at at least two different tiers of perceptual change. At one level, changes can occur between 2-D and 3-D interpretations. Further changes can occur within either the 3-D or 2-D interpretations, such that if a 3-D interpretation has been accepted then there can be further changes between CU and CD at this subordinate level. Most models of perceptual change only consider this subordinate level.

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