Abstract
Multiple object tracking studies typically find a severe capacity limitation on the number of targets that can be accurately tracked. Our research investigated whether this resource is discrete or continuous in nature. The discrete account holds that each target receives a fixed resource amount that can be conceptualized as a pointer or index (Pylyshyn & Storm, 1988). In contrast, the continuous resource account posits a flexible distribution of resources between targets. A critical test for these accounts is the ability of observers to endogenously control the amount of resources allocated to different targets. We investigated this prediction by incentivizing observers to allocate more attention to one target vs. another. Our task required observers to localize targets that moved along circular tracks. We used the mixture model (Bays, Catalao, & Husain, 2009; Zhang & Luck, 2008) to derive estimates of tracking precision and number of objects tracked. Consistent with the continuous resource account, we found that a high priority target was tracked with greater precision (M = 15.31 degrees) than a low priority target (M = 19.30 degrees; t(12) = -4.89, p < .001). It appears that people have flexible control over resource allocation between targets and that increased attention to a target increases tracking precision.
Meeting abstract presented at VSS 2017