Psychology 3041/6014 Spring, 2014 1 of 5 VISUAL PERCEPTION OF MOTION 1) Distinction between object motion and our motion 2) Two types of motion: a) General movement of “something” b) Specific motion of an identified or defined object 3) Notes: a) Perception of movement is a product of the nervous system b) Perception of movement involves more than just the retina c) Perception of movement involves an interplay of more than one sensory system d) Perception of movement requires heuristics, best-guesses, and inexact processesPsychology 3041/6014 Spring, 2014 2 of 5 4) Creating the perception of movement a) Real movement b) Apparent movement c) Induced movement d) Movement aftereffectPsychology 3041/6014 Spring, 2014 3 of 5 5) Detecting movement a) Neural feature detectors & movement perception i) Complex and end-stopped cells ii) Detection circuit iii) Medial temporal (MT) cortex in dorsal (upward) path b) Corollary discharge theory i) Three types of signals accounted for (1) Motor signal (2) Corollary discharge signal (CDS) (3) Image movement signal (IMS) If afferent and efferent directions are both present, they cancel each other out If only one or the other arrives, there must be movementPsychology 3041/6014 Spring, 2014 4 of 5 c) Optic flow field i) How signals move relative to each other in the visual field (or “optical array”) ii) Moving objects cause parts of the optic-array to disappear (be deleted) or reappear (accreted) iii) Results in perception of the occluding object as moving relative to the occluded object iv) Global optic flow (1) Occurs when all elements move in unison (or nearly so) d) Perceptual organization i) Gestalt principles (1) Help pull parts of the view together to help detect relative displacements, hence movement ii) Biological movement (1) Some evidence for neurons (in MT) that respond best to biological (or even species-specific) movement iii) Kinetic depth effect (1) Projection of 3D object onto 2D surface (2) Stationary image looks like 2D object (3) Movement gives 3D aspectPsychology 3041/6014 Spring, 2014 5 of 5 6) Heuristics and theories a) Movements continue in same direction (both linear and rotational) i) Inertia or good continuation b) Occlusion heuristic i) Moving object with tend to occlude the background ii) When occluded, the object still exists 7) Meaning and movement a) Object’s meaning influences movement perception b) Knowledge of the body/physics is