Motion processing and dynamic attention in humans

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Motion processing is critical. Many of our decisions in daily activities are dependent not only on having a good perception of objects in the scene but also having an efficient appreciation of where they are going both if we want to interact with the objects or whether we want to avoid them. We still do not fully understand how we process motion derived from different information sources and we know even less about how we process complex dynamic stimuli information. Objects in a visual scene can be defined by several attributes known to have different mechanisms. The fundamental attributes are energy based and known as 1st order properties and include luminance and colour. Other attributes are not directly defined by energy and known as 2nd order attributes such as contrast and orientation. Although it is clear that that 1st and 2nd order motion perception mechanisms are separable at some level it does not necessarily imply that there is a dedicated 2nd order mechanism. 2nd order motion perception characteristics resemble those reflected by the slower and coarser attention tracking mechanism. Similar conditions apply to colour defined motion. My NSERC programme will address these issues by adopting novel paradigms combining both compensation for non-linearities that may generate luminance artefacts and simultaneously challenge the tracking mechanism using “crowding”. When spatial features are too close to one another, it becomes difficult for the visual system to perceive them although they can be easily seen in isolation and crowding has been shown to be caused by an inability to attend to the stimulus, not to the spatial resolution of the visual system. Motion information in our surrounding is not limited to isolated moving patches of information as described above. Rather we are bombarded with moving information of various speeds and sources and we must integrate this efficiently. For this reason we will use more complex dynamic stimuli where the attention tracking motion mechanisms are highly solicited. Furthermore, perceiving motion in complex environments is rarely accomplished in isolation. Normally we are standing or processing other information simultaneously. Our previous studies have shown that even a simple combined activity such as maintaining balance can influence our ability to process and learn a complex motion task. The other portion of the research programme will address these issues to build a better understanding of how our processing of dynamic stimuli changes with these additional demands. Together, these series of experiments will enrich our comprehension of how we process motion of different types from the most basic level to more life-like complex multitasking conditions.