Q: Suppose a person adapts to a high-contrast grating at $$30^\\circ. $$What would you expect regarding their contrast threshold for gratings at $$30^\\circ$$ compared to $$60^\\circ$$?

Contrast threshold would be higher at $$30^\\circ$$ than at $$60^\\circ.$$

Question 1

Which of the following best describes the concept of selective adaptation in the context of visual perception?

Accepted Answer

Neurons that respond to a specific property become fatigued, leading to decreased firing rate and reduced sensitivity to that property.

Question 2

In a selective adaptation experiment, what is the expected outcome after adapting to a vertical grating?

Accepted Answer

Sensitivity to vertical orientations decreases, requiring a higher contrast threshold to detect vertical bars.

Question 3

What does the contrast threshold measure in the context of selective adaptation experiments?

Accepted Answer

The minimum intensity difference between light and dark bars that can just be detected.

Question 4

After adapting to a high-contrast vertical grating, which of the following changes would you expect in the psychophysical curve for contrast threshold?

Accepted Answer

The curve would show a peak at the vertical orientation, indicating increased threshold.

Question 5

Which statement best explains why adaptation is considered 'selective' in the context of orientation detectors?

Accepted Answer

Only neurons that were actively responding to the adapting orientation show adaptation effects.

Question 6

Suppose a person adapts to a high-contrast grating at $$30^\circ. $$What would you expect regarding their contrast threshold for gratings at $$30^\circ$$ compared to $$60^\circ$$?

Accepted Answer

Contrast threshold would be higher at $$30^\circ$$ than at $$60^\circ.$$

Question 7

Which of the following equations best represents the relationship between contrast threshold ($$T) $$and the intensity difference ($$I) $$between bars in a grating?

Accepted Answer

$$T = I_{max} - I_{min}$$

Question 8

How does the match between the orientation selectivity of neurons and the perceptual effect of selective adaptation support the role of feature detectors in perception?

Accepted Answer

It demonstrates that feature detectors contribute directly to constructing our perception of orientation in complex scenes.

Question 9

A researcher measures a participant's contrast threshold for vertical gratings before and after adaptation. If the threshold increases after adaptation, what does this indicate about the participant's sensitivity?

Accepted Answer

The participant's sensitivity to vertical gratings has decreased.

Question 10

In a crowded shopping mall, which visual process is most likely being influenced by feature detectors that have undergone selective adaptation?

Accepted Answer

The ability to distinguish between different orientations of objects in the scene.

Question 11

If a participant adapts to a $$45^\circ$$ grating and then is tested on gratings at $$0^\circ$$, $$45^\circ$$, and $$90^\circ$$, which orientation will likely show the highest contrast threshold?

Accepted Answer

$$45^\circ$$

Question 12

Which of the following best describes the physiological effect of selective adaptation on neurons?

Accepted Answer

Neurons decrease their firing rate and fire less when the stimulus is immediately presented again.

Question 13

Why is the psychophysical curve for selective adaptation slightly wider than the orientation tuning curve for a single cortical neuron?

Accepted Answer

Because the adapting stimulus affects some neurons that respond to orientations near the adapting orientation.

Question 14

Which experimental step is crucial for demonstrating the effect of selective adaptation on orientation sensitivity?

Accepted Answer

Measuring contrast threshold before and after adaptation to a specific orientation.

Question 15

If the contrast threshold for a vertical grating increases from $$0.05 to$$ $$0.15$$ after adaptation, what does this change indicate?

Accepted Answer

The participant now requires a greater intensity difference to detect the vertical bars.

Question 16

Which of the following real-world scenarios best illustrates the role of feature detectors in perception as supported by selective adaptation experiments?

Accepted Answer

Navigating a busy street and distinguishing the orientation of crosswalk lines.

Question 17

What is the main conclusion drawn from the similarity between the psychophysical selective adaptation curve and the orientation tuning curve of a cortical neuron?

Accepted Answer

Feature detectors in the visual cortex play a direct role in perception.

Question 18

Which formula would you use to calculate the contrast threshold ($$T) if $$the intensity of the light bar is $$I_L$$ and the intensity of the dark bar is $$I_D$$?

Accepted Answer

$$T = |I_L - I_D|$$

Question 19

A participant adapts to a $$60^\circ$$ grating. Which orientation will show the greatest decrease in sensitivity?

Accepted Answer

$$60^\circ$$

Question 20

Which of the following is NOT a plausible effect of selective adaptation on visual perception?

Accepted Answer

Increased sensitivity to the adapting orientation.

Selective Adaptation and Psychophysical Measurement in Visual Perception

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