In many everyday situations observers are required to simultaneously attend multiple targets of different importance (e.g. driving, security screenings). This thesis explores participants’ ability to unequally allocate their attention to different targets or regions of the visual field in both dynamic (Chapters 2 and 3) and static settings (Chapter 4). In a series of three Multiple Object Tracking experiments (Chapters 2 and 3) evidence is provided for the plausibility to allocate attention unequally across different moving targets (Chapter 2) or regions of the visual field (Chapter 3) in a goal-directed manner. As priority associated with a target or region increased, more attention was allocated to it as indicated by improved tracking performance (for direction of heading judgments) and prolonged eye gaze. Stronger evidence for unequal attention prioritisation is also found in cases of foveal versus peripheral tracking indicating the functional role of eye movements during this task. Alternatively, in a series of four hybrid search task experiments (Chapter 4), evidence is provided for a graded prioritisation of different static targets during visual search, based on the priority (i.e. prevalence: Experiment 4; or reward: Experiment 5) associated with each one. This was indicated by quicker and more accurate responses as target priority increased. When the two forms of priority were combined, results indicated that unequal reward distribution (where lower prevalence items are more rewarded; Experiment 6), was found to diminish the effect of prevalence, compared to an equal reward distribution (Experiment 7) as indicated by faster response times and fewer misses. Results of the current thesis support a flexible structure of our attentional resource which can be unequally allocated in a goal-directed manner. Findings also provide practical implications for training observers in real-life settings on how to unequally allocate their limited attentional resource in an efficient manner.
Unequal attention prioritisation of multiple moving and static targets.
Hadjipanayi, V. (Author). 9 May 2023
Student thesis: Doctoral Thesis › Doctor of Philosophy (PhD)