Unequal Attention Allocation in Multiple Object Tracking

  • Emily Crowe

Student thesis: Doctoral ThesisDoctor of Philosophy (PhD)


Tracking multiple objects as they move around the environment is a crucial everyday skill. This thesis investigated whether attention can be split unequally between moving objects to determine the nature of the attentional resource that underlies tracking. Fixed architectural models argue that a limited number of slots support tracking whereas flexible models propose a continuous pool of resources. A modified MOT task was developed which required participants to split their attention unequally between moving objects. Under both theories, unequal attention splitting is theoretically possible. However, each theory predicts a different pattern of results in an unequal attention splitting paradigm. Under a fixed account, a stepped increase in performance as target importance increases is predicted whereas, under a flexible account, a graded increase in performance is predicted. Chapters 2 and 3 showed that participants could split attention unequally in response to target priority and reward. Across four experiments, there were mixed results regarding the nature (i.e. stepped or graded) of the increase in performance as target importance increases. Therefore, hybrid models of MOT need to be developed which combine components of both fixed and flexible theories. Chapter 4 found no evidence for attentional narrowing under conditions of anxiety but further demonstrated unequal attention splitting. The overarching conclusion of this thesis is that unequal attention splitting is possible, indicating some flexibility to the attentional resource. Further research using the unequal attention splitting paradigm has the potential to distinguish theories of multiple object tracking.
Date of Award25 Jun 2019
Original languageEnglish
Awarding Institution
  • The University of Bristol
SupervisorChris Kent (Supervisor) & Angela S Attwood (Supervisor)

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