The word "mood" is a loaded term. Often, moodiness, particularly as it applies to women, is interpreted as irrational and self-indulgent.
But moods -- those nebulous and fluctuating states of feeling -- do have a biological purpose and may even be useful for helping us to better understand our surroundings, according to New York psychiatrist Dr. Julie Holland, author of Moody Bitches.
Women's moods are a "healthy, adaptive part of our biology," Holland has argued.
A bold new theory of moodiness, published last week in the journal Trends in Cognitive Sciences, adds credence to this claim, suggesting that men and women's natural emotional fluctuations actually serve an important purpose: helping us to better adapt to changes in our environment.
The new study suggests that moods help us to learn from our personal experiences so that we can better respond to similar situations next time.
"It’s long been known that mood biases our judgments and perceptions, but this effect has usually been regarded as irrational or disadvantageous," Dr. Eran Eldar, a neuroscientist who studies emotion at University College London and one of the study's authors, told The Huffington Post in an email.
"By computationally analyzing causes and consequences of mood that are evident in the laboratory, we showed that mood’s biasing impact can, in fact, serve an adaptive role."
Here's an example: When a stock trader experiences an unexpected financial gain, it would undoubtedly improve her mood. This positive mood, in turn, would likely inspire her to take more risks, thereby adapting to a market environment that's on the rise.
A sizable body of research has shown that emotional states can powerfully color our perceptions and judgments. The new theory -- based on brain imaging data exploring the association between moods and monetary loss or gain -- suggests that we learn from experiences that are colored by our moods. Our expectations then reflect not only changes in reward availability (for instance, the rising stock) but also changes in the overall availability of reward in our environment.
Therefore, moods are an efficient means of learning about the environment, and they help us to quickly adapt to change.
"Our moods reflect inferences that things are generally getting better or worse for us, and they impact our behavior so as to adapt to these changes," Eldar said.
As the researchers note, positive and negative moods are most useful when they're relatively short-lived, persisting only until our expectations are in line with a change in reward. Then, most people will return to a baseline emotional state.
It's easy to see how humans may have evolved in some way to be moody, and to use fluctuations in mood as a source of information about one's surroundings.
"The effect of mood may have helped survival by ensuring quick adaptation to changes that possess an underlying momentum -- for instance, gradual changes in weather in springtime -- or that affect the general availability of resources, for instance, changes in the social status of an animal," Eldar said.
Of course, moods aren't always reliable gauges of a situation -- or as the saying in Cognitive Behavioral Therapy goes, "feelings aren't facts." Still, being more in tune with our moods can only help us to become more aware of how our emotions color our judgments and perceptions, both in a positive and a negative sense. And in defining the vital functions of our moods, scientists may one day come to better understand the root causes of mood disorders like bipolar disorder and depression.
Far from being "irrational," the researchers conclude, moods are a healthy and indeed evolutionarily adaptive aspect of human cognition.
"Being moody at times may be a small price to pay for the ability to adapt quickly when facing momentous environmental changes," they wrote.
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