Motion trajectories are typically rendered based on an algorithm resulting in “Brownian motion like” object motion (cf. Pylyshyn and Storm 1988; “Brownian motion” is a term used in physical chemistry to describe the movement of particles in suspension, resulting from collisions with rapidly moving atoms or molecules). There are restrictions regarding sudden and large velocity changes (a factor referred to as object inertia, Pylyshyn 2004), giving object motion a certain appearance of Inhibitors,research,lifescience,medical “biologicity.” Moreover, motion trajectories are affected by object
“behavior”: in the incidence of intersection, two objects can overlap with each other (Pylyshyn 2004), bounce off each other (selleck bio Bahrami 2003), or go round each other (Alvarez and Franconeri 2007). Such constraints restrict the set of possible spatial coordinates to which an object can proceed from one frame to another. However, from the remaining set, coordinates are usually Inhibitors,research,lifescience,medical chosen in an arbitrary manner, yielding essentially unpredictable object motion. Cognitive processes during MOT Behavioral fty720 PP2a results on MOT cannot readily be explained by “spotlight” theories of attention (Posner 1980). Rather, Yantis (1992) found empirical evidence that target objects are
“grouped,” that is, cognitively represented as if belonging to one virtual Inhibitors,research,lifescience,medical object. During tracking, instead of continuously shifting the locus of attention back and forth between objects, target identity is supposedly maintained via a holistic representation in the form of said virtual Inhibitors,research,lifescience,medical object. Furthermore, Pylyshyn and Storm (1988) suggested that object identity is maintained through “mental reference tokens.” In an early stage of visual perception, salient objects in a visual display can be “indexed,” a mechanism that individuates and keeps track of said objects without the necessity to categorize or conceptualize them (Pylyshyn 2001). On a similar notion, Kahneman and colleagues suggested the existence Inhibitors,research,lifescience,medical of object files, that is, temporary visual representations of real world
objects (Kahneman and Treisman 1984; Kahneman et al. 1992). Object files GSK-3 store information on object surface features, such as shape or texture, and spatiotemporal characteristics (Mitroff and Alvarez 2007). Depending on their availability and reliability in a given situation, both types of information can be used to maintain object correspondence in the incidence of brief occlusions of an observed moving object, (Hollingworth and Franconeri 2009; Papenmeier et al. in press). However, in situations where no distinguishing surface information is available (such as in the MOT paradigm), spatiotemporal information appears to be of key significance to the maintenance of object file representations. Indeed, while random changes in object shape or object color did not impair tracking performance (Bahrami 2003; unless, for instance, targets and distractors swapped colors during occlusion, see Huff et al.