18 Questions
During dark adaptation, why does sensitivity increase as the visual system becomes dark adapted?
Due to the rod cells becoming more sensitive
At what retinal eccentricity does rod density reach a peak, resulting in lowest thresholds and highest sensitivity?
18-degree retinal eccentricity
In the classic dark adaptation study, why were stimuli presented on the temporal retina at 20-degree eccentricity?
To avoid the blind spot
What property describes the eye's ability to add up quanta over a certain area?
Spatial summation
Why is spatial summation critical diameter different for rods and cones?
Rods and cones have different receptive fields
Which type of vision is dominant in the first few minutes of dark adaptation before the rods take over?
Photopic vision
What is dark adaptation?
The process of the visual system adjusting to low light after being in high light levels.
During dark adaptation, the first 5-10 minutes are primarily dominated by which type of vision?
Cones
Where is the greatest sensitivity under photopic conditions?
Fovea
How long does it typically take for full dark adaptation to occur?
40 minutes
What is the Stiles-Crawford effect related to?
Effect of light rays angle on cone brightness perception
Spatial summation in the eyes refers to:
The eyes' capability to summate or add up quanta over an area.
What varies as the size (diameter) of a central stimulus increases?
Proportion of cones and rods stimulated
Why does the perceived size of an object change as we get closer to it?
Due to the principles of simple trigonometry
What can be easily calculated for circular spot stimuli in psychophysics experiments?
Area by measuring diameter
In dark adaptation, what needs to be considered about stimulus size and retinal sensitivity?
Measuring size in x and y dimensions
How can visual angle be calculated when knowing the absolute size and viewing distance?
$\theta = \arctan (h/d)$
Why is measuring the area occupied by a stimulus useful in psychophysics?
To estimate perceived size accurately
Test your knowledge on how the size of a central stimulus affects the stimulation of cones and rods in the eye. Explore the measurement of object size, distance, and visual angle in two dimensions while considering perceptual interests.
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