US High School Psychology Practice Exam 2025 - Free Practice Questions and Study Guide

The primary function of rods and cones in the visual system is to convert light into electrochemical impulses. Rods and cones are specialized photoreceptor cells located in the retina of the eye. Rods are highly sensitive to light and enable vision in low-light conditions, while cones are responsible for color vision and function best in bright light.

When light hits these photoreceptors, they undergo a biochemical change, leading to the generation of nerve impulses. These impulses are then transmitted to the brain via the optic nerve, allowing us to perceive images. This fundamental process of transducing light into electrical signals is crucial for our visual perception, making the option that emphasizes this conversion function the correct choice.

The other options involve functions unrelated to the specific roles of rods and cones, such as sound processing, motion detection, or peripheral vision enhancement, which are not the primary roles of these photoreceptor types.