Psych 3312 1st EditionExam # 4 Chapters 8-10Chapter 8 What are the 3 main functions of motion perception? a. Motion helps to understand events in our environment b. Motion attracts attention c. Motion provides information about objects 2. What is akinetopsia & what are the kinds of problems that someone with this condition has. a. Akinetopsia=blindness to motion. b. Kinds of problems someone with akinetopsia has include difficulty pouring drinks b/c they can’t see the liquid rising in the cup and can’t tell when to stop. c. People suddenly appear or disappear because people w/akinetopsia can’t see them approaching.d. Crossing the street at night is dangerous for them b/c the car might seem far away, but then would appear very near w/o warning.3. What are 4 ways that we can perceive motion. a. Using real motion. Real motion=actual motion of an object.b. Apparent motion=when an illusion of movement occurs btwn 2 stimuli but no actual real motion btwn the stimuli. c. Induced motion=when motion of 1 object (usually a large one) causes a nearby stationary object to appear to move.d. Motion aftereffects=occurs when viewing a moving stimulus for 30-60 sec. causes a stationary stimulus to appear to move.4. What was Larson’s research on real & apparent motion? a. Showed 3 types of displays to a person in fMRI scanner. i. Control condition in which 2 dots in slightly diff positions were flashed simultaneously. ii. Real motion display in which a small dot moved back & forthiii. Apparent motion display in which dots were flashed one right after the other so they appeared to move back & forth. iv. fMRI results showed that brain is activated in the space that represents the area btwn the 2 dots (figure 8.7, pg. 180) where movement was perceived but no stimuli present.5. What are the 3 situations that we need to understand when explaining motion perception. a. Looking straight ahead as an object moves past (human walking across a room) b. Following a moving object with your eyesc. Looking around the room6. What are the major principles of Gibson’s approach to motion perception. a. Optic array=structure created by surfaces, textures, & countours of environmentb. Local disturbance in optic array=when 1 object moves relative to the environment, so stationary background is covered & uncovered by moving object. Local disturbance indicates that the object is moving relative to environment.c. Global optic flow=fact that everything moves at once in response to movement of the observer’s eyes or body. d. Motion perceived when 1 part of visual scene moves relative to rest of scene, & no motionperceived when the entire field moves, or remains stationary.7. What is the Reichardt detector explanation for motion perception. a. Reichardt detector=neural circuit that resulted in neurons that fire to movement in 1 direction. Excitation & inhibition arranged so that movement in 1 direction creates inhibition that eliminates neural responding, whereas movement in opposite direction creates excitation that enhances neural responding.8. State the major principles of the corollary discharge theory of motion perception, and discuss how each of the three situations (from #5 above) are explained. a. Corollary discharge theory takes eye movement into account. b. Image displacement signal (IDS)=occurs when image moves across receptors in retina. Signal occurs when the man walks across the woman’s field of view while she stares straight ahead.c. Motor signal (MS)=occurs when signal is sent from brain to the eye muscles. Signal occurs when the woman moves her eyes to follow the man as he walks across the room.d. Corollary discharge signal (CDS)=copy of motor signal that instead of going to eye muscles sent to diff place in the brain. Example would be using a “cc” in an email message to someone. Email goes to the person it’s originally addressed to, and a copy of the email also simultaneously sent to someone else at another address.9. What is the aperture problem & explain how the visual system solves this problem. a. Aperture problem=when only viewing a small portion of a larger stimulus can result in misleading info about the direction in which the stimulus is moving.b. Visual system solves this problem by pooling responses from a # of neurons. MT cortex may be involved.10. Be able to define the shortest path constraint in apparent motion and discuss how this principle operates for biological motion. a. Shortest path constraint=when apparent movement tends to occur along the shortest pathbtwn 2 stimuli. b. Motor cortex activated when perceived movements are humanly possible but not activated when perceived movements are not possible 11. Discuss the cues used to determine when events begin and end. a. Event=a segment of time at a particular location that is perceived by observers to have a beginning and an ending. b. Perception of motion plays important role in separating activities into meaningful environments. c. Event boundary=point in time when one event ends & another begins.d. Connection of events to motion perception involve changes in the nature of motion & associated w/event boundaries. Chapter 9 1. What are the functions of color vision. a. Serves important signaling functions both natural & made by humans.b. Color helps identify & classify things.c. Helps facilitate perceptual organization (ability to tell 1 object from another & pick out objects within scenes) d. Ability to detect colored food e. Helps us identify & recognize things we can see easily. 2. How do wavelength, intensity, and saturation affect our color experience? a. Saturation=amount of whiteness in a chromatic color. Change the light’s intensity to make colors brighter or dimmer, or add white to change the color’s saturation.b. By changing wavelength, intensity, & saturation, we create around a million + diff colors. 3. How do mixing paints & mixing lights differ? How are they similar? a. Mixing Lightsi. All of the light that is reflected from the surface by each light when alone is also reflected when the lights are superimposed. ii. When 2 spots are superimposed, added-together light contains short, medium, & long wavelengths, which result in perception of white. Mixing lights involves adding up wavelengths of each light in the mixture, mixing lights is called additive color mixture. b. Mixing Paints i. When colored paints are mixed together, both paints still absorb the same wavelengths they absorbed when alone, so