Whether I am more sensitive to reward or punishment is not something I would share in a professional meeting. Yet my eyes may reflect this information continuously. People just don’t notice it because we aren’t aware of each other’s eye blinks.
In the previous blog, we met someone who can precisely track people’s eyes with an eye tracking camera. Her data suggest that people who blink their eyes more often are more sensitive to reward, as you’ll read below.
Eye blinks are related to dopamine
How often you blink your eyes in a second is called your blink rate. Scientists think that the blink rate is related to the level of dopamine, your brains reward messenger. Joanne, who works in the Psychology department of the VU University, discovered a sign that your blink rate is also related to how well you learn from reward.
A sign, not a fact? Yes, to proof that your blink rate reflects your reward sensitivity, a researcher should first change your natural reward sensitivity and then test whether your blink rate changes. A big task! Joanne didn’t do that, she just observed a clear pattern in her data showing that frequent blinking went hand in hand with learning from reward.
Fast blinkers learn well from reward
As you learned in the previous blog, your pupil dilates when a reward surprises you. Naturally, the surprise would be bigger if you cared more about the reward. In other words, when you’d be sensitive to reward. As I mentioned above, a fast blink rate could reveal a brain that contains plenty of the reward messenger dopamine. Therefore, it would be sensitive to reward.
In her experiment, Joanne let people participate in a lottery where different lot colours were associated with an 80% chance of reward or loss. Indeed, the fast blinking participants showed greater pupil dilation to unexpected reward. To check how well the participants learned, Joanne sometimes changed which lot color signalled reward or loss. Again, she found that the fast blinking participants were quicker to report the change. You can read the full results here.
But what happens to the people who blink less often? Joanne’s results suggest that these people are more sensitive to loss. Their pupils dilated most to unexpected loss.