Guest Talk: Casimir Ludwig

26 January 2016
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Control over fixation in active visual sampling

Decision-making frequently involves gathering information from multiple sources, which then has to be combined to make some overall decision about the "state" of the environment. For perceptual decisions, visual information is actively sampled during periods of steady fixation, interspersed with rapid gaze shifts to novel objects or regions of interest. During a fixation we have to perform three tasks: (i) analyse the currently fixated object with the high resolution fovea (foveal analysis); (ii) select a target from the periphery for the next fixation (target selection); and (iii) decide when to move on. I will present experimental work that tests how foveal analysis and target selection are coordinated in a single fixation. In addition, I will assess the role of foveal and peripheral evidence, as well as the pre-trial brain state, in the control of fixation duration.