Which of the following phenomena is a function of the distribution of the rods and cones in the retina?
A) The moon looks much larger near the horizon than it looks when it is higher in the sky.
B) The light from distant stars moving rapidly away from us shifts toward the red end of the spectrum.
C) Stars can be seen during the daytime but only with difficulty.
D) A dim star viewed at night may disappear when you look directly at it, but reappear when you look to one side of it.

Question

Quizplus · Accepted Answer

The distribution of rods and cones in the retina affects our ability to detect faint objects in our peripheral vision versus our central vision. This is known as the Purkinje effect. When we look directly at a dim star, we are using our central vision which is dominated by cones, but when we look slightly to the side, we are using our peripheral vision which is more sensitive to low light levels and dominated by rods. This allows us to see the dim star again. Choice A is related to the moon illusion and has to do with how our brain perceives the size of objects based on their context. Choice B is related to the Doppler effect, which has to do with the relative motion of objects emitting or reflecting light. Choice C is not directly related to the distribution of rods and cones in the retina, but rather to the scattering of light in the atmosphere.

Which of the Following Phenomena Is a Function of the Distribution