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Visual selection as an object-oriented mechanism: an ecological perspective towards the primacy of objects over space

Nikolova, Atanaska 2016. Visual selection as an object-oriented mechanism: an ecological perspective towards the primacy of objects over space. PhD Thesis, Cardiff University.
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The visual world consists of objects. Planning or performing actions requires some form of engagement with an object. This requirement has shaped our perceptual systems to be highly tuned to ‘objecthood’ and construct objects from minimal available information. This project aimed to explore to what extent the importance of objects influences visual selection: the mechanism that prioritises the necessary information subsets in order to perform an action, and investigate on what basis this information is prioritised. Current visual selection theories argue prioritisation is accomplished as a combination between space-based and object-based mechanisms, with space having a prime role in how information is selected from the environment. This project proposes an alternative view, suggesting selection is a fully object-oriented mechanism and space-based effects are a consequence of object-based selection. This possibility was tested in three empirical chapters with the use of cueing paradigms, in the context of immediate perceptual decisions (luminance change identification), and colour change detection involving visuo-spatial short term memory. The key premise is that there is an intrinsic link between the spatial separation of any two points and the likelihood they belong to the same object. If these points are perceived to be within the same object, visual selection is not affected by the distance between them and they are equally prioritised for action. Prioritisation level decreases with increasing distance only when this likelihood of object- belongingness is low, because points closer together have a higher probability to originate from the same object. The current work tested this premise by varying independently object-belongingness and spatial proximity of cue-target stimuli pairs. Results indicated that visual selection is fully object-oriented and can be distance-independent. It is proposed that the perceptual system assesses the probability that information is integrated into potential objects, and then prioritises selection based on this object-belongingness probability.

Item Type: Thesis (PhD)
Date Type: Completion
Status: Unpublished
Schools: Psychology
Subjects: B Philosophy. Psychology. Religion > BF Psychology
Date of First Compliant Deposit: 24 January 2017
Last Modified: 12 Nov 2021 13:28

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