Why can't we see colors well in the dark?

If you've ever gotten dressed in the dark and later realized that the shirt you were wearing was not the color you thought it was, you're not alone. Identifying colors can be challenging in the dark, and even in low light, different colors can look remarkably similar. 

But why is it harder to discern colors in the dark than it is in bright light?

Humans' ability to perceive color varies due to how we see under different lighting conditions. Human eyes contain two types of photoreceptors, or nerve cells that detect light: rods and cones. Each photoreceptor contains light-absorbing molecules, called photopigments, that undergo a chemical change when struck by light. This triggers a chain of events in the photoreceptor, prompting it to send signals to the brain.

Rods are responsible for enabling vision in the dark, known as scotopic vision. They're made of layers and layers of photopigments, said Sara Patterson, a neuroscientist at the University of Rochester in New York. 

Related: The 5 human senses — and a few more you might not know about 

Rods are particularly good at picking up light even when it's dark because "every single one of those stacks is a chance for photons to get absorbed," she said. Photons are particles of electromagnetic radiation — in this case, visible light — and rods can be activated by exposure to relatively few photons.

Cones, on the other hand, are responsible for vision in bright light, or photopic vision. Most people have three types of cone cells, each of which is sensitive to a different range of wavelengths of visible light, which correspond to different colors. Small changes in the light-absorbing molecules in different cones make them specialized in detecting red, green or blue light.