The Function of Functional Division

Abstract: The human cortical visual system is divided into two distinct processing streams, which on the dominant model have proprietary functional roles: a 'ventral' stream processing 'vision for perception', and a 'dorsal' stream processing 'vision for action'. Independently of this division, there exists an early 'threat-detection' system, constituted by connections between the LGN and amygdala, which triggers 'fight or flight' responses to threatening stimuli. Assuming these claims about the local function of the processing streams is correct, we’re left with a more fundamental question about the nature of the functionally divided visual system: Why are there multiple visual streams? Why does the mind divide and conquer rather than unite and build? In my talk, I will present three challenges to the dominant task-based answer to this question and argue for a new computation-based division in visual processing. According to the latter, the multiple processing streams enact different computational approaches in parallel in a coordinated solution to perception/action problems.