Uploaded August 2024 | Updated September 2026, 1 week ago
When you step from a lit room into a dark one — perhaps to nab some nighttime chocolate — you might struggle to spot the light switch. But if you pause for a few minutes, you’ll notice your vision slowly begin to improve. This phenomenon relies on two nerve cells in our retinas: cones and rods. Cones help us see colors clearly in well-lit environments, while rods are optimized for seeing black and white in low-lit ones.
Rods produce a protein called rhodopsin, which depletes in settings with a lot of light to prevent your eyes from becoming overstimulated. In the dark, however, rhodopsin production rachets up over time. This process sharpens your low-light vision — but it can’t offer the same level of detail cones do in bright light. The brain also helps adjust the sensitivity of our vision in a process called contrast gain control, fine-tuning our sight to better spot the chocolate in the dark.
This is a video from the 2024 Brain Awareness Video Contest: brainfacts.org/for-educators/programs-and-events/brain-awareness-video-contest
Created by Christoph Koenig.
Watch on BrainFacts: brainfacts.org/thinking-sensing-and-behaving/vision/2024/a-chocolate-heist-neuroscience-of-dark-adaptation-092324
When you step from a lit room into a dark one — perhaps to nab some nighttime chocolate — you might struggle to spot the light switch. But if you pause for a few minutes, you’ll notice your vision slowly begin to improve. This phenomenon relies on two nerve cells in our retinas: cones and rods. Cones help us see colors clearly in well-lit environments, while rods are optimized for seeing black and white in low-lit ones.
Rods produce a protein called rhodopsin, which depletes in settings with a lot of light to prevent your eyes from becoming overstimulated. In the dark, however, rhodopsin production rachets up over time. This process sharpens your low-light vision — but it can’t offer the same level of detail cones do in bright light. The brain also helps adjust the sensitivity of our vision in a process called contrast gain control, fine-tuning our sight to better spot the chocolate in the dark.
This is a video from the 2024 Brain Awareness Video Contest: brainfacts.org/for-educators/programs-and-events/brain-awareness-video-contest
Created by Christoph Koenig.
Watch on BrainFacts: brainfacts.org/thinking-sensing-and-behaving/vision/2024/a-chocolate-heist-neuroscience-of-dark-adaptation-092324
