Which photoreceptor in the human eye is primarily responsible for color vision in daylight?

• A. Cones
• B. Rods
• C. Ganglion cells
• D. Bipolar cells

Answer: (A)

Cones are the photoreceptors responsible for color vision in daylight. They are specialized for bright light and come in three types, each sensitive to different wavelengths corresponding roughly to blue, green, and red. The brain interprets color by comparing the signals from these cone types, which lets you perceive a full spectrum of colors with sharp detail when conditions are well lit. In contrast, rods are much more sensitive to light and provide grayscale, low-light vision but don’t distinguish colors well, so they don’t support color vision in daylight. Ganglion and bipolar cells are neurons that relay and process signals from photoreceptors, but the actual color-detecting input comes from the cones.