Research

Why do humans (and possibly, animals) have positive emotions? Positive emotions are unique adaptations in the scheem of evolution. Seemingly, they do not provide inherent sustenance or protection. Some theorists have argued that positive emotions are markers of well-being or that they trigger approach behavior. Others have thought that positive emotions are merely offsets to negative emotions to make life more bearable. However, these explanations are not truly complete and leave many questions unanswered. Professor Fredrickson's research program challenges the assumptions of traditional models of emotion and provides a unique viewpoint on the function of positive emotions.

Here are some of the research lines without our laboratory. Please note that this is only a brief synopsis. For the sources of the ideas, please see our publications.

The Broaden-and-Build Theory of Positive Emotions

Central to many existing theories of emotion is the concept of specific-action tendencies - the idea that emotions prepare the body both physically and psychologically to act in particular ways. For example, anger creates the urge to attack, fear causes an urge to escape and disgust leads to the urge to expel. From this framework, positive emotions posed a puzzle.

Emotions like joy, serenity and gratitude don't seem as useful as fear, anger or disgust. The bodily changes, urges to act and the facial expressions produced by positive emotions are not as specific or as obviously relevant to survival as those sparked by negative emotions. If positive emotions didn't promote our ancestors' survival in life-threatening situations, then what good were they? How did they survive evolutionary pressures? Did they have any adaptive value at all?

Broad Build Figure 1

Barbara Fredrickson developed the Broaden-and-Build Theory of Positive Emotions to explain the mechanics of how positive emotions were important to survival. According to the theory, positive emotions expand cognition and behavioral tendencies. Taking issue with the view that all emotions lead to specific action tendencies, the theory argues that positive emotions increase the number of potential behavioral options. Instead, emotions should be cast as leading to changes in "momentary thought-action repertoires" - a range of potential actions the body and mind are prepared to take.

The expanded cognitive flexibility evident during positive emotional states results in resource building that becomes useful over time. Even though a positive emotional state is only momentary, the benefits last in the form of traits, social bonds, and abilities that endure into the future. The implication of this work is that positive emotions have inherent value to human growth and development and cultivation of these emotions will help people lead fuller lives.

For more information, check out these articles or our publications:

Fredrickson (2003) American Scientist
Fredrickson (2001) American Psychologist
Fredrickson (1998) Review of General Psychology

The Broaden Hypothesis

One central hypothesis, drawn from Fredrickson's broaden-and-build theory, is the broaden hypothesis. It states that discrete positive emotions broaden the scopes of attention and cognition and lead to a widened array of thoughts and action impulses in the mind. A corollary to this hypothesis is that negative emotions shrink these same arrays. Several studies from our lab provide converging support for this hypothesis.

1. Global Bias in Global-Local Visual Processing: We induced positive, negative, and neutral emotions using short video clips. Following the emotion induction, we assessed breadth of attention to "the big picture" or "details." Participants who saw the positive emotion videos showed a bias towards seeing stimuli globally.

Figure 1

2. Enlarging Thought-Action Repertoires: Similar to the study described above, participants watched emotion-eliciting videos. Afterwards, participants indicated all of the action urges they had at that moment. It turned out that people induced to feel a positive emotion listed a greater number of action-urges than people induced to feel negative or neutral emotions.

Figure 2

3. Inclusive social thinking: A highly robust finding is that people exhibit a tendency to recognize people of their same race better than those of a different race. The effect is referred to as the "Own-Race Bias" in face perception. In one of our experiments, Caucasian participants viewed Black and White faces and were later asked to recall if they had seen the faces previously. Additionally, by random assignment, they viewed a video to elicit joy, fear, or neutrality prior to the facial recognition task. Results showed that when we induce positive emotions in people, the own-race bias is is eliminated.

Figure 3

Fredrickson & Branigan (2005) Cognition and Emotion
Johnson & Fredrickson (2005) Psychological Science

The Build Hypothesis

If we accept the premise that positive emotions broaden people's mindsets what would be the purpose? The build hypothesis explains the functionality of positive emotions. Unlike negative emotions during which the body becomes prepared physically and mentally for immediate action, the adaptive value of positive emotions lies not in the moment, but over the long-term. From an evolutionary standpoint, the resources accrued through repeated experiences of positive emotions enhance the odds of survival and of living long enough to reproduce.

The resources gained through positive emotional experiences may be physical, social, psychological or intellectual. Currently our lab aims to explore the many possible resources that may be augmented as a result of positive emotion experience. Here are some of the candidate resources:

    • Physical Resources - sleep quality, immunity from illnesses and diseases
    • Social - expanded social connections, social support
    • Intellectual - creativity, mindfulness
    • Psychological - trait resilience, optimism

This line of research is expanding. We've found experimental support for the build hypothesis using a manipulation that increased the level of positive emotions people experienced. In a 2-month study, participants either attended a workshop cultivating positive emotions through meditation or had no intervention whatsoever. The results indicated that increasing the level of positive emotions leads to numerous benefits to health and well-being.

The Undoing Hypothesis

Past research has shown that anger, fear and sadness each elicit distinct responses in the autonomic nervous system. In direct contrast, the positive emotions appeared to have no distinguishable autonomic responses. Positive emotions do not themselves generate cardiovascular reactivity, but instead quell any existing cardiovascular reactivity caused by negative emotions. Put differently, a prior state of negative emotional arousal may be a necessary backdrop to illuminate the cardiovascular impact of positive emotions. Assuming (as most emotion theorists do) that the cardiovascular reactivity sparked by certain negative emotions prepares the body for specific actions, the broaden-and-build theory suggests that positive emotions can speed recovery from - or undo - this cardiovascular reactivity and return the body to mid-range levels of activation suitable for pursuing a wider range of behavioral options. According to this view, positive emotions have a unique ability to down-regulate lingeri ng negative emotions and the psychological and physiological states they generate.

In one of our studies, we gave participants an acute stressor - the possibility of giving a public speech. As participants prepare for this speech their bodies exhibit increased sympathetic nervous system activation (sweaty palms, increased heart rate, increased blood pressure). After a minute or so of this heightened state of arousal, participants learn that they don't have to give the speech after all and instead view a randomly assigned video clip that generates a positive or negative emotion, or a state of neutrality. We measured the amount of time it took each person to recover from the anxiety about the possible speech. Results indicated that positive emotions led to a quicker return to a resting state than neutral or negative emotions.

Undo Figure 1

Fredrickson, Mancuso, Branigan, & Tugade (2000) Motivation and Emotion
Fredrickson & Levenson (1998) Cognition and Emotion