Unit 3.7, 3.8, 3.9

Question 1

What experiement did Brady, et al (2008) perform?

Answer 1

a task where subjects looked at 2500 objects in the training phase and then chose which of two objects they had seen in a test phase

Question 2

What were the results of the Brady, et al (2008) experiment?

Answer 2

when the objects were:
- of different types: 92% correct
- the same category: 88% correct
- in different states: 87% correct

Question 3

What is boundary extension in the context of scene memory?

Answer 3

an error in scene memory where individuals confidently remember seeing a surrounding region of a scene that was not visible in the studied view (Intraub & Richardson, 1989)

Question 4

How does scene context influence object detection?

Answer 4

provides important cues for object detection

Question 5

How do relational violations influence object detection?

Answer 5

it can make the perception of objects in scenes harder

Question 6

What are the five relational violations identified by Biederman et al. (1982)?

Answer 6

1. Support: Object does not appear to be resting on a surface.
2. Interposition: Background appears to pass through the object.
3. Probability: Object is unlikely to appear in the scene.
4. Position: Object is likely to occur in the scene but is in an unlikely position.
5. Size: Object appears too large or too small relative to other objects in the scene.

Question 7

What is inattentional blindness?

Answer 7

the phenomenon of not being able to perceive things that are in plain sight. It is caused by an absence of attention to the unseen object

Question 8

What is change blindness?

Answer 8

• failure to notice a change between two scenes
• perception depends on the meaning of change

Question 9

What does EEG data reveal about scene processing?

Answer 9

the brain can detect the presence of an animal in an image within 150 milliseconds

Question 10

What is the difference in processing time for rough layouts versus detailed descriptions in scene perception?

Answer 10

In Fei-Fei et al. (2007) studies,
- participants could grasp a rough layout of a scene in about 27 milliseconds
- a more accurate description could be generated after 67 milliseconds
- very detailed descriptions could be achieved in 500 milliseconds.

Question 11

How does exposure time affect scene detail recognition?

Answer 11

The more time individuals have to process a scene, the more details they can recognize; brief exposures (like 500 ms) are sufficient for a rich representation of scene content

Question 12

What is the role of the Parahippocampal Place Area (PPA) in scene processing?

Answer 12

• prefers scenes over faces or objects - contains a robust neural representation of categories of natural scenes
• the category is robust to the way the scenes are presented (eg. line drawings versus color photographs)

Question 13

What are the six categories of natural scenes that the PPA can discriminate between?

Answer 13

Beaches, city streets, forests, highways, mountains, and offices.

Question 14

What methodology was used to train and test the decoding algorithm for categorizing scenes in the PPA?

Answer 14

A pattern recognition algorithm (SVM) was trained and tested on fMRI activity while participants viewed images

Question 15

What does decoding accuracy indicate in the context of fMRI studies of the PPA?

Answer 15

Decoding accuracy reflects how well the algorithm can correctly categorize scenes based on brain activity patterns.

Question 16

In the study by Walther et al. (2011), what was the finding regarding line drawings versus color photographs?

Answer 16

The decoding accuracy from line drawings was at the same level as that from color photographs, indicating that certain features of the scenes are preserved regardless of the presentation format

Question 17

What is the basic design of a neural circuit for detecting rightward motion?

Answer 17

The circuit consists of a chain of adjacent position detectors wired pairwise into a motion detection unit, which indicates motion when an object, like a bug, crawls across the line.

Question 18

How does the Reichardt motion detector determine speed?

Answer 18

Speed is determined by the distance of the signal sent to the detectors; if a moving object is too slow or too fast, signals will arrive at the comparators at different times.

Question 19

What happens if an object moves in the wrong direction according to the Reichardt motion detector?

Answer 19

signals will arrive at the comparators at different times

Question 20

What is a limitation of the Reichardt motion detector?

Answer 20

may respond to stationary patterns or flicker, leading to false motion signals

Question 21

What is the function of the Opponent Reichardt Motion Detector?

Answer 21

consists of two Reichardt detectors tuned to opposite directions of motion, where the outputs are subtracted from one another

Question 22

What is “apparent motion”?

Answer 22

the illusory impression of smooth motion resulting from the rapid alternation of objects appearing in different locations in quick succession

Question 23

What is the significance of the interstimulus interval (ISI) in apparent motion?

Answer 23

the time between the onset of two frames in apparent motion

Question 24

What is perceptual phase space?

Answer 24

the appearance of a display can have qualitatively different states depending on the ISI and displacement

Question 25

What is the significance of the stimulus onset asynchrony (SOA) in apparent motion?

Answer 25

time difference between the onset of two stimuli

Question 26

How can apparent motion be utilized in film and animation?

Answer 26

use rapid sequences of images to create the illusion of motion

Question 27

What is the correspondence problem of motion?

Answer 27

the problem faced by the motion detection system of knowing which feature in frame 2 corresponds to a particular feature in frame 1

Question 28

How does the brain resolve the correspondence problem in apparent motion?

Answer 28

The brain uses Gestalt principles (like proximity, color, and shape) to determine which features in one frame correspond to features in the next frame

Question 29

What is the Ternus effect, and how does it relate to apparent motion?

Answer 29

a phenomenon where two dots appear to move together as a group due to the manipulation of timing and blank frames

Question 30

What is motion entrainment?

Answer 30

the addition of flanker dots that cause the center for to appear in motion behind a square occluder

Question 31

What are kinetic boundaries?

Answer 31

visual cues that help distinguish a moving object from its background

Question 32

What is first-order motion?

Answer 32

the motion of an object that is defined by changes in luminance

Question 33

What is second-order motion?

Answer 33

The motion of an object that is defined by changes in contrast or texture, but no by luminance

Question 34

What is the difference between first-order and second-order motion in terms of neural processing?

Answer 34

processed by different neural systems in the brain

Question 35

What is the significance of displacement in second-order motion?

Answer 35

the displacement must be small (less than 1/4 degree).

Question 36

What is an example of how second-order motion can be useful in nature?

Answer 36

may help detect well-camouflaged animals