AbstractsComputer Science

The attentional capacity limitation of tracking multiple moving objects has been discussed expansively by various theoreticians. The research reported in this thesis assessed the limits of object tracking with a series of systematic psychophysical investigations. Chapter 2 reports evidence that the limits of object tracking are directly due to the resources allocated to each target rather than caused by spatial interference (Franconeri et al., 2008; 2010). With widely-spaced target configurations, the maximum speed observers could track targets declined as the number of targets increased. Chapter 4 provides evidence supporting the claim that tracking resources are flexibly shared among targets, with the fastest-moving target receiving more resources than the slower-moving target. These results provide concrete evidence to support the assumptions of resource theory: continuously allocated resources, limited capacity, and flexible resource allocation. The current research also demonstrated some specific findings regarding resource theory in object tracking. Chapters 3 and 4 confirmed previous findings obtained using different methodologies (Alvarez & Cavanagh, 2005) by showing that tracking resources are largely hemisphere-specific, and effectively demonstrated that performance for a fast-moving target is very sensitive to the amount of resources allocated. Furthermore, Chapter 5 showed that observers lost the tracked target if distractors occupied a location close to the time a target occupied it, suggesting that the mechanism of tracking also has a limited temporal resolution, and that reducing the resource allocated to each target reduces temporal resolution. To conclude, the findings of all the experiments are discussed in the context of various resource theories.