Emotional experiences can induce physiological and internal brain states that persist for long periods of time—an emotional “hangover.”
“How we remember events is not just a consequence of the external world we experience, but is also strongly influenced by our internal states—and these internal states can persist and color future experiences,” explains Lila Davachi, an associate professor in New York University’s department of psychology and Center for Neural Science.
“‘Emotion’ is a state of mind,” Davachi continues. “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.”
We have known for quite some time that emotional experiences stick in the memory better than non-emotional ones do. However, in the Nature Neuroscience study, the researchers demonstrate that non-emotional experiences that followed emotional ones were also better remembered on a later memory test.
To do so, subjects viewed a series of scene images that contained emotional content and elicited arousal. Approximately 10 to 30 minutes later, one group then also viewed a series of non-emotional, ordinary scene images. Another group of subjects viewed the non-emotional scenes first followed by the emotional ones. Both physiological arousal, measured in skin conductance, and brain activity, using fMRI, were monitored in both groups of subjects. Six hours later, the subjects were administered a memory test of the images previously viewed.
The results showed that the subjects who were exposed to the emotion-evoking stimuli first had better long-term recall of the neutral images subsequently presented compared to the group who were exposed to the same neutral images first, before the emotional images.
The fMRI results point to an explanation for this outcome.
Specifically, these data show that the brain states associated with emotional experiences carried over for 20 to 30 minutes and influenced the way the subjects processed and remembered future experiences that are not emotional.
“We see that memory for non-emotional experiences is better if they are encountered after an emotional event,” observes Davachi, senior author of the study.
Coauthors are from NYU, UC Berkeley, and the University of Geneva. Dart Neuroscience, along with grants from the National Institute of Mental Health, the Swiss National Science Foundation, the German Research Foundation, and the European Community Seventh Framework Programme supported the work.
Source: New York University
Original Study DOI: 10.1038/nn.4468
by James Devitt-NYU