The role of synchrony in perceptual binding of facial movement

Brown, Benjamin B. (2018) The role of synchrony in perceptual binding of facial movement. PhD thesis, University of Nottingham.

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Abstract

Faces are some of the most complex and important sources of information in the visual world. Their motion transmits a rich stream of social signals that human observers nonetheless seem able to interpret effortlessly. The aim of this thesis is to investigate how the timing of coordinated facial movement is represented by the visual system.

Chapter 1 reviews the current knowledge of several major themes in the face perception literature. It first reviews three classic paradigms that each have a bearing on the present work, before introducing the theoretical issues to which they have most often been applied: holistic face processing and expertise. This chapter then reviews the major models of face processing and its neural implementation, before turning to expressive or dynamic faces, and finally recent reports of timing-mediated cross-feature interactions.

Chapter 2 begins by describing the overall stimulus and paradigm (many details of which apply across behavioural experiments), before presenting the first three experiments. Together, these confirm that perception of one feature's motion is not independent of concurrent motion in another feature, despite the latter being spatially separate and task-irrelevant.

Chapter 3 presents Experiments 4 and 5, which reveal the specificity of these interdependencies to certain dynamic feature relationships (particularly synchrony) and the right visual hemifield, respectively.

Chapter 4 presents Experiments 6 and 7, which employ visual adaptation to probe the neural encoding of relative feature timing. Experiment 6 discounts an orientation-like channel-based account, instead finding a general reduction in performance following adaptation to asynchronous feature movement. Experiment 7 discounts recalibration of perceptual models centred on synchrony as an explanation.

Chapter 5 presents a combined dynamic localiser and phase-encoded fMRI experiment, which found greater modulation by relative feature timing of facial motion sensitive brain areas. Using a simple contrastive analysis, this experiment provides the first evidence that regions involved in facial motion processing prefer certain feature relative timings.

Chapter 6 concludes this thesis by reviewing, contextualising, and critiquing the present work. Included is a summary of the original contribution to knowledge, and potential future directions.

Item Type: Thesis (University of Nottingham only) (PhD)
Supervisors: Johnston, Alan
Schluppeck, Denis
Subjects: B Philosophy. Psychology. Religion > BF Psychology
Faculties/Schools: UK Campuses > Faculty of Science > School of Psychology
Item ID: 50421
Depositing User: Brown, Ben
Date Deposited: 27 Sep 2021 14:44
Last Modified: 27 Sep 2021 14:46
URI: https://eprints.nottingham.ac.uk/id/eprint/50421

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