Question

Although the two horizontal lines are the same length, our experience tells us that a more distant object can create the same-sized retinal image only if it is larger. What is this called:

a) Perceptual Constancy
b) Visual Perspective
c) Size Illusion
d) Relative Size

Answer 1

The illusion where two horizontal lines of the same length appear different due to distance cues is known as relative size, explained by perceptual constancy. The eye adjusts its lens through a process called accommodation to maintain a consistent perception of object sizes at various distances.

Step-by-step explanation:

The phenomenon described involves an understanding of how perceived size can be influenced by depth cues, and is known as relative size. Perceptual constancy allows us to understand that an object's size does not actually change despite variations in distance or the angle from which it is viewed. While an object at point A produces a larger retinal image compared to the same object at point B because of the angle it subtends, our brain automatically accounts for distance and maintains a perception of consistent size.

This perception is managed through a process in the eye called accommodation, where the ciliary muscles change the shape of the eye lens to focus on objects at different distances. The lens-to-retina distance must remain constant for clear vision, hence the need for the focal length adjustment. This adjustment allows us to have a stable vision and perceive objects clearly from 25 cm to effectively infinity under standard conditions.