Psych 421 - Sensation & Perception

Chapter 8 - Motion - Study Notes

Dr. Carpenter

Rev. 10/98

I.    Motion Perception

            A.    Intro to motion

            B.    Is there a simple way to account for motion perception?

            C.    Real Motion

                        1.    Thresholds of motion perception - velocity detection threshold

                        2.    Biological motion

                                    a.    Point-Light displays - what are they and why are they of interest

                                    b.    What can they tell us?

                                    c.     Biological motion and gender   

                                    d.    How can we mask biological motion? What works and what doesn't?

                                    e.    What does it tell us about perception?

                        3.    Motion of the observer

                                    a.    How do we perceive a stable world while in motion?

                                    b.    Perceiving the direction of observer motion - optic flow fields

                                    c.    Self-motion illusion

                                    d.    Perception of speed - rate of looming

            D.    Apparent (Illusory) Motion

                        1.    Stroboscopic movement - phi movement

                        2.    Autokinesis

                        3.    Induced movement

                        4.    Movement aftereffects

                        5.    Motion in still pictures

            E.    Physiological Basis of Motion Perception

                        1.    A lot of magno system and some parvo system

                        2.    Akinetopsia

            F.    How do we explain motion perception?

                        1.    Corollary Discharge Theory

                                    a.    Describe it

                                    b.    Four outcomes

                                                1)    Looking ahead with no motion

                                                2)    Eyes stationary but motion of an object

                                                3)    Eyes looking over a stationary world

                                                4)    Eyes tracking a moving object

                                    c.    What happens if you disrupt the normal corollary discharge?

                        2.    Direct Perception (Gibson) - 6 sources of information

                                    a.    Relative movement

                                    b.    Occlusion & disocclusion

                                    c.    Image size

                                    d.    Motion parallax

                                    e.    Motion perspective

                                    f.    Binocular cues

                        3.    Computational Approach - rich stimuli & problem solving

                                    a.    Correspondence problem

                                    b.    Short-range process - role of parasol cells

                                    c.    Long-range process                

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