Quiz 3 - Chapters 7-9 Flashcards
(25 cards)
The ecological approach emerged as a reaction
b. to the artificiality of laboratory approach to studying vision.
Which statement is true concerning the focus of expansion?
b. It always occurs at the point you are moving toward.
“Optical flow neurons” have been found in the monkey’s
b. medial superior temporal (MST) area
Using the visual direction strategy, walkers stay on target by
c. keeping their body pointed toward the destination.
Affordances
. provide the observer possibilities for action.
Patients with ________ often have difficulty pointing at objects and adjusting their reach “paths” to avoid obstacles.
a. optic ataxia
Which of the following factors has not been shown to influence action-based object perception?
b. Describing the object to someone before interacting with it.
The condition of the patient of Zihl, et al., who had cortical lesions that affected her motion perception, is called
akinetopsia.
Our ability to perceive movement when reading “message boards” used in advertising, is based on
a. apparent movement.
According to Corollary Discharge Theory, movement is perceived when
c. the comparator receives the corollary discharge signal alone or image displacement signal alone.
Mira gently pushes on her eye with her finger. Because her eye muscles push against the force of her finger, which keeps the image in the same location, she perceives the visual scene
a. to be jiggling.
A monkey with an intact MT cortex can detect the direction of moving dots when coherence is ____%, while a monkey that has had the MT cortex lesioned detects the direction of the moving dots when coherence is _____%.
a. 1-2; 10-20
In an apparent motion demonstration, two pictures are used. In one picture a person’s fist is located behind his head; in the other, the person’s fist is located in front of their face at the same height. When slowly alternating between these pictures (less the five times a second), what apparent motion would result?
a. The fist would appear to go around the side of the head.
In one study, Zacks et al. (2009) recorded someone making a sandwich and asked participants to press a button when they thought one action was complete. The results of the study indicated that _______were indicative of the end of an action.
b. changes in speed
Adding more white to a color changes the color’s
d. saturation.
Blue and yellow paints mixed together yield
c. green.
The maximum absorption for the long-wavelength cone pigment is at ____ nm.
c. 558
A unilateral dichromat
a. has trichromatic vision in one eye and dichromatic vision in the other eye.
Nora adapts to a yellow stimulus for about 30 seconds. She will then see an afterimage that appears to be
c. blue.
The case of “Mr. I,” described in the beginning of the chapter, supports the idea that color is processed in
d. a “color center” in the cortex.
Discuss research that shows how vision is important in performing a somersault.
When gymnasts have to perform a somersault, they need to take in consideration their placement in the air to execute the somersault and then finish it ready to land correctly on the floor.
If vision wasn’t important for this trick to be accomplished, and instead, the gymnast just learned how to do it by memorizing every step of the way, then it wouldn’t matter if the gymnast performed somersault using his vision ( eyes open) or not ( eyes closed).
However, research by Benoit Bardy and Makel Laurent (1998) concluded that expert gymnasts perform better with their eyes open. According to this research, after filming expert gymnasts and analyzing the footage, they were able to notice gymnasts adapting their movement in the air to achieve their end-goal. This means that, if they made any mistakes during each step of the process, they were able to correct it to ensure they still ended the somersault on the right spot. If the experienced gymnasts had their eyes closed, they wouldn’t be able to make this correction ( as they wouldn’t know exactly where the end spot was) and therefore their performance might not be the same.
On the other hand, according to the same research, when they filmed new gymnasts, it seems that closing their eyes didn’t make as much difference in their end-result and overall performance. They concluded that experience gymnasts knew how to use their perception to adapt their movements but new gymnasts still hadn’t developed their perception skills and thus, having visual information didn’t make the same impact as it did on experience gymnasts.
Describe evidence from monkey studies that suggests that mirror neurons do more than respond to patterns of motion.
Mirror neurons respond to both an organism performing an action or watching another organism perform an action.
However, mirror neurons are not just responding to the pattern of motion.
According to research on monkeys by Gallese et.al.,(1996) and Rizzolati et al.,(200), when the monkeys were just looking at a food they had no response and when they watched the food being grabbed by something other than a hand, there was not a lot of response either.
Because the monkeys didn’t really respond to the food being grabbed using something else ( in this experiment, a pair of pliers) , we can use this as evidence against the fact that mirror neurons are just responding to pattern of motion.
(a) What does Gibson mean by the “optic array”?
(b) Specify how changes in the optic array affect movement perception.
A) According to Gibson, information provided by the environment can be used to understand perception. This information that is present in the environment he called “ optic array” or the structure created by the surfaces, textures and contours of the environment.
B) For Gibson, movement of the observer causes changes in the optic array.
When a person moves across a field of view, some parts of the optic array are covered and some other parts are uncovered as the movement continues. Gibson called this “ local disturbance in the optic array”. And it occurs when a parson moves in the environment in relation to a still background. For Gibson, the information provided by the local disturbance in the optic array allows us to perceive that the person is moving in comparison to the background/environment.
When the observer scans a scene, and moves their eyes left to right, everything around the observer moved to the left of their field of view. This would also happen if the observer would walk through the scene ( instead of watching someone walking).
The fact that everything moves at once in response to movement of the observer’s eyes or body is called global optic flow; this signals that the environment is stationary. According to Gibson, movement is perceived when on part of the visual scene moves relative to the rest of the scene and no motion is perceived when the entire filed moves, or remains stationary.
Explain (with examples) the difference between additive color mixture and subtractive color mixture.
When colored lights are superimposed all of the light that is reflected from the surface by each light when alone is also reflected when lights are superimposed. This means that mixing lights is an additive colour mixture.
Therefore, when looking at two spots superimposed by light, i.e one blue and one yellow, the result would be a white spot where the lights are added together because it contains small, medium and long wavelengths added.
When paints are mixed, both paints still absorb the same wavelengths they absorbed when alone, so the only wavelengths reflected are those that are reflected by both paints in common. This means that mixing paint is subtractive colour mixture.
When mixing blue and yellow paint, only the medium wavelengths are reflected by both paints in common, and thus the mixture of blue and yellow paints appear green.
