Visual Perception and Stimulus Size Quiz

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During dark adaptation, why does sensitivity increase as the visual system becomes dark adapted?

Due to the rod cells becoming more sensitive (correct)

Due to a change in cone dominance

Due to an increase in luminance

Due to a decrease in rod density

At what retinal eccentricity does rod density reach a peak, resulting in lowest thresholds and highest sensitivity?

15-degree retinal eccentricity

18-degree retinal eccentricity (correct)

10-degree retinal eccentricity

5-degree retinal eccentricity

In the classic dark adaptation study, why were stimuli presented on the temporal retina at 20-degree eccentricity?

To test cone dominance

To measure spatial summation

To avoid the blind spot (correct)

To maximize rod sensitivity

What property describes the eye's ability to add up quanta over a certain area?

Spatial summation Signup and view all the answers

Why is spatial summation critical diameter different for rods and cones?

Rods and cones have different receptive fields Signup and view all the answers

Which type of vision is dominant in the first few minutes of dark adaptation before the rods take over?

Photopic vision Signup and view all the answers

What is dark adaptation?

The process of the visual system adjusting to low light after being in high light levels. Signup and view all the answers

During dark adaptation, the first 5-10 minutes are primarily dominated by which type of vision?

Cones Signup and view all the answers

Where is the greatest sensitivity under photopic conditions?

Fovea Signup and view all the answers

How long does it typically take for full dark adaptation to occur?

40 minutes Signup and view all the answers

What is the Stiles-Crawford effect related to?

Effect of light rays angle on cone brightness perception Signup and view all the answers

Spatial summation in the eyes refers to:

The eyes' capability to summate or add up quanta over an area. Signup and view all the answers

What varies as the size (diameter) of a central stimulus increases?

Proportion of cones and rods stimulated Signup and view all the answers

Why does the perceived size of an object change as we get closer to it?

Due to the principles of simple trigonometry Signup and view all the answers

What can be easily calculated for circular spot stimuli in psychophysics experiments?

Area by measuring diameter Signup and view all the answers

In dark adaptation, what needs to be considered about stimulus size and retinal sensitivity?

Measuring size in x and y dimensions Signup and view all the answers

How can visual angle be calculated when knowing the absolute size and viewing distance?

$\theta = \arctan (h/d)$ Signup and view all the answers

Why is measuring the area occupied by a stimulus useful in psychophysics?

To estimate perceived size accurately Signup and view all the answers