A generic problem in vision is to know which information drives the perception of a stimulus. We address this problem in a case study that involves the perceptual reversal of an ambiguous image (here, Dali's painting the Slave Market with the Disappearing Bust of Voltaire, 1940). Ambiguous images, such as Dali's painting, are perfect stimuli for investigating the information in a stimulus that underlies its perception because the bottom-up information underlying the different interpretations is identical. In Experiment 1, we use Bubbles (Gosselin & Schyns, 2001) to disambiguate the image and to determine the specific visual information that drives each possible perception (here, the nuns vs. the bust of Voltaire). We found that the nature of this information is grounded in different spatial filters analyzing the image. Experiments 2 and 3 validate that this information does determine the selective perception of the ambiguous image. Using dynamic colored noise (computed by randomising the phase angles of the information driving each percept) observers adapted the spatial frequency channels mediating one of the two percepts, globally across the visual field in experiment 2 and locally in experiment 3. In a transfer phase, following global adaptation, we induce a perception of the ambiguous image that is orthogonal to the adapting frequency in experiment 2. Experiment 3 tests the locality of this spatial frequency information by confining it to the region underlying each percept, again observers experience a perception opposite to the adapting frequency. Together, the results of this local frequency-specific adaptation on the perception or recognition of complex figurative patterns suggests a new method to investigate the links between recognition and perception. This highlights the importance of understanding the information contained in a stimulus and how the use of this information modifies perception.
- ambiguous images