The broaden-and-build theory of positive emotions suggests that positive emotions (viz. enjoyment/happiness/joy, and perhaps interest/anticipation) broaden one's awareness and encourage novel, varied, and exploratory thoughts and actions. Over time, this broadened behavioral repertoire builds skills and resources. For example, curiosity about a landscape becomes valuable navigational knowledge; pleasant interactions with a stranger become a supportive friendship; aimless physical play becomes exercise and physical excellence.
This is in contrast to negative emotions, which prompt narrow, immediate survival-oriented behaviors. For example, the negative emotion of anxiety leads to the specific fight-or-flight response for immediate survival. On the other hand, positive emotions do not have any immediate survival value, because they take one's mind off immediate needs and stressors. However, over time, the skills and resources built by broadened behavior enhance survival.
When a life-threatening event occurs, people typically have a narrow range of possible responses or urges. Having a limited number of urges, called specific action tendencies, quickens a person’s response time in these situations. While negative emotions experienced during life-threatening situations narrow an individual’s thought-action repertoire, positive emotions present new possibilities, providing the individual with a wider range of thoughts and actions to choose to draw upon.
The broaden-and-build theory is an exploration of the evolved function of positive emotions. It was developed by Barbara Fredrickson starting around 1998 and is commonly associated with positive psychology.
The broaden-and-build theory has substantial support. Barbara Fredrickson has conducted randomized controlled lab studies in which participants are randomly assigned to watch films that induce positive emotions such as amusement and contentment, negative emotions such as fear and sadness, or no emotions. Compared to people in the other conditions, participants who experience positive emotions show heightened levels of creativity, inventiveness, and "big picture" perceptual focus. Longitudinal intervention studies show that positive emotions play a role in the development of long-term resource such as psychological resilience and flourishing. Not only are positive emotions a sign of flourishing, or thriving and expanding in life rather than simply surviving life, they can also help create flourishing in the present and in the future. Because positive emotions positively broaden and build one’s thought-action repertoires they lead to increased resources and more satisfied lives.
Broaden-and-build and resilience 
Positive emotions can undo lingering negative emotions because they put the negative emotions in a broader perspective. If an individual can cultivate these positive emotions, he or she can use them to help cope with negative emotions. Positive emotions help people who are distressed deal with what is occurring and move forward and away from the negative emotions. Also, because of their broadening effect, positive emotions increase the probability of finding good in future events. Individuals high in resiliency are those who experience more positive emotions even in the face of stress. Having these positive emotions is what helps an individual build up resources to cope with negative emotional experiences.
Enduring effects of positive emotions 
Interestingly, happiness is not only the result of, but is often present before success and high-functioning. According to Fredrickson, positive emotions build individual’s long-lasting psychological, intellectual, physical and social resources. The resources gained through positive emotions outlive the emotions from which they were acquired. Resources build up over time and increase the individual’s overall well-being. Increased well-being leads to more positive emotions which lead to higher resilience. Higher resilience can then lead to increased well-being which would create an upward spiral of continually improving well-being. Individuals who are happy exhibit many positive, long-lasting traits such as better coping, a longer life, and increased health.
Fredrickson’s original Broaden-and-Build model focused solely on the broadening of attention through positive emotions. Today, proposals are in favor of incorporating the importance of a narrowing component in addition to broadening to build personal resources. Negative emotions are generally involved in the narrowing process. The adverse effects of negative emotions can be counterbalanced and undone by positive emotions. Therefore, beneficial aspects can be experienced without harmful effects if both positive and negative emotions are experienced in proportion.
The creative process, which is a key component that allows widening of the mind to lead to building personal resources, is often studied in respect to both sides of the emotional spectrum. Studies demonstrate that those who are more naturally creative experience much wider mood swings, spending a lot of time in both positive and negative emotional spaces depending on what they are trying to accomplish at the time. Too much time on either side can be detrimental to this process. If too much time is spent in positive emotions without appropriate counterbalance, an individual is likely to become aloof and unfocused.
The creative process is often discussed in two stages. The first stage is defocused attention which is followed by focused attention. Fredrickson alludes to defocused attention in her Broaden-and-Build model. Defocused attention occurs when a person is able to see a wide range of possibilities and take in as much information as possible. The second stage, focused attention, takes place when more negative emotions are felt. During focused attention, a person analyzes the possibilities that they found during defocused attention. Without this process, concrete ideas do not form. This theory lends itself to the inclusion of negative, narrowing emotions in this model. Another theory verifying this inclusion is the whole-brain hypothesis of creativity. The theory states that the defocused process uses a greater portion of the right side of the brain, whereas the focused process uses more of the left side of the brain. Creativity necessitates the communication between the two hemispheres allowing these processes to work together to form coherent theories and develop personal skills. This theory provides support for a more integrated model that includes narrowing as well as broadening in order to build.
Meditation and the hedonic treadmill 
Positive emotions are very temporary, thus leading to the theory of the hedonic treadmill where an individual is constantly trying to find new ways to experience positivity because their old techniques have become ineffective. The Broaden-and-Build model addresses this issue by arguing that life satisfaction is achieved through a pathway that includes positive emotions causing a person to build resources which can be drawn upon to improve life satisfaction for extended periods of time. This path is much more effective than a path that attempts to go straight from positive emotions to life-satisfaction due to the hedonic treadmill effect. Meditation is a means bywhich some researchers have proven that a person can broaden their mind and experience the positive emotions needed to build personal resources. Specifically, Loving-Kindness Meditation has been proven effective. In this type of meditation, a participant is first asked to think about a person that they already think of in a warm way. Then they are asked to expand their focus and positive feelings first to themselves, then to a widening array of people. This allows for immediate positive emotions and provides for more long-term effects.
Loving-kindness meditation has been shown to increase such positive emotions as love, joy, gratitude, contentment, hope, pride, interest, amusement, and awe. However, the study that was done on these emotions was done over a nine-week period by Fredrickson, Cohn, Coffey, Peck, and Finkel. The period of time allowed them to see that these positive emotions were not developed immediately. The slow progression provided evidence that the positive effects built resources that allowed for more positive experience in the future. Therefore, this process was able to side-step the hedonic treadmill, reinforce that the broaden-and-build model is accurate, and demonstrate that loving-kindness meditation is an effective method to facilitate the initial broadening. Taken together, these studies set the theory into motion.
Writing about intensely positive emotions 
A study conducted by Chad M. Burton and Laura A. King showed that writing about intensely positive experiences improved subjects’ happiness and health. Subjects were instructed to write about an intensely positive experience for twenty minutes each day for three days while a control group was instructed to write about a neutral topic for the same period of time. Following the study, the experimental group demonstrated an increase in happiness levels while the control group did not. The researchers recorded how many times the subjects went to the doctor for an illness over the next three months and found that the experimental group visited the doctor’s office far less often than the control group. These results can be interpreted using Fredrickson’s broaden-and-build theory. Reliving positive experiences induces positive emotions, and positive emotions help us to broaden-and-build. Therefore, subjects who wrote about positive experiences were able to use those positive emotions to broaden their experiences and build relationships and skills. This broadening-and-building gave the subjects long-term benefits in well-being. Those subjects who did not write about positive experiences did not experience an increase in positive emotions and therefore did not build the resources to help them feel happier and healthier in the following months.
Religion and broaden-and-build 
Positive emotion has been implicated as an important component in the link between religion and health. Experiencing positive emotions helps people to become more resilient, more creative, wiser, more virtuous, more socially integrated, and physically healthier.
People who participate in certain religious practices, data suggests, experience similar positive benefits. Researchers, such as B.L. Fredrickson, have based research on this link. The aspect that makes certain religions beneficial to people is the fact that they are “built on a belief of greater meaning in life”. This belief in greater meaning is what helps cultivate positive emotions. People are able to find meaning in anything from chance occurrences, such as running in to an old friend in the store, to extreme hardships, such as losing a spouse.
- Compton, William C, (2005). "2". An Introduction to Positive Psychology. Wadsworth Publishing. pp. 23–40. ISBN 0-534-64453-8.
- Fredrickson, BL (2001). "The Role of Positive Emotions in Positive Psychology". American Psychologist 56 (3): 218–226. doi:10.1037/0003-066X.56.3.218. PMID 11315248.
- Fredrickson, B. L. (2003). The value of positive emotions. American Scientist, 91, 330-335.
- Cohn, MA; BL Fredrickson (2006). "Beyond the Moment, Beyond the Self: Shard Ground between Selective Investment Theory and the Broaden-and-Build Theory of Positive Emotions". Psychological Inquiry.
- Tugade, MM; BL Fredrickson (2004). "Resilient Individuals Use Positive Emotions to Bounce Back from Negative Emotional Experiences". Journal of Personality and Social Psychology 86 (2): 320–333.
- Rathunde, K (2000). "Broadening and Narrowing in the Creative Process: A Commentary on Fredrickson's "Broaden-and-Build" Model". Prevention & Treatment 3 (1).
- Fredrickson, B.L.; M.A. Cohn, K.A. Coffey, J. Pek, S.M. Finkel (2008). "Open Hearts Build Lives: Positive Emotions, Induced Through Loving-Kindness Mediation, Build Consequential Personal Resources". Journal of Personality and Social Psychology 95 (5): 1045–1062. doi:10.1037/a0013262. PMID 18954193.
- Burton, Chad; Laura King (April 2004). "The Health Benefits of Writing about Intensely Positive Experiences". Science Direct-- Journal of Research in Personality.
- Fredrickson, B.L. (11/3/2002). "How Does Religion Benefit Health and Well-Being? Are Positive Emotions Active Indredients?". Psychological Enquiry 13 (3).