Whether or not you experience good or bad emotions over the holidays most likely depends on you and your family dynamic, but the end result will likely be the same — exhaustion. If you’re sitting around the house now amid empty gift boxes and cookie crumbs with a distinct sense of blah, take comfort in knowing that you’re experiencing a scientifically verifiable emotional hangover.

This state of being was characterized in a new study published Monday in the journal Nature Neuroscience. The researchers behind the study argue that emotional brain states from the past can carry over into the present, influence neutral experiences, and enhance future memory formation, and together these effects constitute the emotional hangover. In other words, the emotional experiences a person has will bias their interpretation of new, unrelated experiences.

“‘Emotion’ is a state of mind,” lead author Lila Davachi, Ph.D., a psychologist at New York University, said in a statement. “These findings make clear that our cognition is highly influenced by preceding experiences and, specifically, that emotional brain states can persist for long periods of time.”

Strong emotions will influence future emotional states.
Strong emotions will influence future emotional states.

To come to this conclusion, Davachi and her team asked a group of study participants to look at a series of images designed to elicit emotional arousal. Then, between 10 and 30 minutes later, they were asked to look at ordinary, non-emotional images. A second group of participants looked at the same images, but in the reverse order. Both groups were asked to complete a memory test based on what they saw six hours later. All the while, their physiological arousal and brain activity were being measured.

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The researchers found that the group that looked at emotional images first were better able to recall the neutral images than those who saw them afterward. When they examined the fMRI data measuring the participants’ brain activity, they found that brain states after looking at emotional images remained the same for 20 to 30 minutes after the actual emotion-inducing activity. This, in turn, influenced how the subjects processed and remembered the images that were not emotional.

“How we remember events is not just a consequence of the external world we experience,” says Davachi, “but is also strongly influenced by our internal states — and these internal states can persist and color future experiences.”

So if you’re feeling a bit down after the holidays, try to give yourself a break. It’s not, despite how it may feel, an erratic reaction to present events; rather, your brain is simply trying to emotionally reconcile with its past.

Photos via Giphy (1, 2)