Abstract
Holistic representations emphasize the global structure of objects rather than their local elements. The current study focused on impossible objects, 2D shapes that seem to represent objects that could not exist in real 3D space. It has been suggested that, unlike possible objects, impossible objects cannot be represented in a holistic manner because they lack a valid structural description. Here, we used behavioral repetition priming and fMRI adaptation to further explore this account. In the behavioral experiment, comparable repetition priming effects were found for possible and impossible objects, suggesting that these object classes are represented in a similar manner. Additionally, the priming effects were not correlated with the number of local structural violations that elicited the "impossibility" of these objects, suggesting a global processing style for impossible objects. In the imaging experiment, we used fMRI adaptation to compare the neural representations subserving the perception of possible and impossible objects. Importantly, equivalent adaptation effects were observed for possible and impossible objects in high order, object selective visual cortex, suggesting that similar representations mediate the perception of these two object classes. Taken together, these findings suggest that the perception of possible and impossible objects is mediated by overlapping cognitive and neural mechanisms. This study further stresses the centrality of holistic processing in human visual perception and suggests that this processing style is applied even on atypical stimuli such as impossible objects.
Meeting abstract presented at VSS 2012