Motivation and emotion/Book/2014/Happiness and health

Happiness and health:
How does happiness influence our health?

Multimedia presentation (5 min)

Overview

Case study: Ellie's Story

"I am fat", "I am ugly". The quiet whispers coming from her mouth when she looks at herself in the mirror every morning. "I am NOT happy"

We often hear a dissatisfaction in regards to one's appearance. It is a very common problem in the female adolescent population, and the numbers are only increasing in other demographics. Most people assume that in order to fix this, they have to workout, eat a limited amount of food every day and that food being low caloried meals, that they need to get cosmetic surgery or need to wear a lot of makeup. Little do they know that the root of their discomfort is actually deeper than that. In this chapter we will explore the many factors demonstrating how the source of her unhappiness is actually physiological and social as well. Throughout the chapter, follow the purple boxes to see how what you learn can help Ellie.

At one point or another in life, we have all been told that “laughter is the best medicine”. We’ve been told that if you “smile and nod”, the simple act of doing so will allow you to remain positive in a stressful or frustrating situation.

From this, we may ask ourselves, what is happiness? What is health? How do we maintain these and how do they influence one another? In order to answer these questions, we must consider the various aspects of each one of those terms.

Definitions

Happiness

Smiling and laughing are two of the most common signs of happiness. The Science Channel (2011) [1]) describes happiness as a “state of well-being and contentment”. As you experience life, happiness will come and go. It is a mental and emotional state that is regulated by neurochemicals in the body, hormones as well as the activation of the Brain left prefrontal lobe (Science Channel, 2011). In example, when adolescents go through puberty, or when a woman goes through menopause, the body’s hormone levels change and cause an experience called a “mood swing”. A “mood swing” is a noticeable rapid change in someone’s mood (Grohol, 2013[2]).

There are various types of neurochemicals and hormones that are involved in the regulation of happiness, each with their respective role and outcomes. Some examples are Dopamine, Cortisol, Oxytocin, Endorphins and Serotonin. These are to be discussed later in the chapter.

There are two main types of happiness: Hedonic happiness and Eudaimonic type.

Hedonic

Considered as “instant gratification”. Those who are said to be hedonically happy are those who find happiness in the small things, whether it is buying a new dress or enjoying a meal (Kemsley, T., 2013)[3]. Reeve, J. (2009) describes hedonic happiness as “the totality of one’s pleasurable moments”.

Ellie's Story: The simple act of treating herself to a nice piece of apple pie, one of favorite desserts, or playing one of her favorite sports after a long day at school will allow her to increase her hedonic happiness. This will allow her to increase her psychological health, and even her social health (if she hangs out with friends) or physiological health (playing the sport) depending on the activity that she chooses

Eudaimonic

A deeper sense of satisfaction, those who are eudaimonically happy are happy due to a deeper, meaningful reason. This type of happiness is connect to a sense of purpose and gratification (Kemsely, T., 2013). Reeve, J. (2009) describes eudaimonic happiness as “self-realization. […] involves engaging oneself in meaningful pursuits and in doing what is worth doing. […] It is the actualization of the self and it is realized through the pursuit and realization of personal authenticity and growth.

Ellie's Story: If Ellie were to join a club for a sport that she enjoys, she will engage herself in conversations and get to know people. The simple act of getting to know people and sharing stories and information about herself with them will increase her Eudaimonic happiness. This is because she is making a deeper connection with life, by gaining friends and sharing what she has to offer. This will most definitely increase her social health, and can even lead to psychological health in the long run (due to the emotional regulation).

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Health Health is a very misunderstood word. If you were to ask your family, friends or peers, the majority of them would tell you that being healthy is eating nutritious meals and engaging in physical activity on a regular basis. When asked online “What do YOU consider healthy” on myfitnesspal.com (My Fitness Pal, 2012)[4], the participants would mention that for them, being healthy is the “[ability to have] a relationship with food such that you’re able to enjoy “bad foods” on occasion but also get in proper amounts of protein, stick to your calorie goals and get in some activity daily” (My Fitness Pal, 2012) or “[being] healthy is to eat as many whole foods as possible” (My Fitness Pal, 2012). Figure 2. There are many ways to increase your physiological health. These individuals chose to participate in a 12 mile bike ride. This will mainly have an impact on their cardiovascular and muscular health. According to the World Health Organization (WHO), health is “a state of complete physical, mental and social well-being and not merely the absence of disease or illness” (World Health Organization, 2003)[5]. It is a state of equilibrium (balance) that an individual has established within themselves, and in relation to his social and physical environment (The Meanings of Health and its Promotion, 2006)[6]. This being said, there are various aspects of health that we must consider in order to determine its influence on happiness. There are 3 types of health that we will examine: physiological health, psychological health and social health. Physiological Also known as physical health. Physiological health is easily mistaken as being the only component of health as people will consider themselves being healthy if their appearance follows the stereotypical image of fit. Physiological health refers to how our bodies function and adapt in terms of our physical and chemical processes. It is usually characterized by a lack of illness and a small percentage of body fat and a high percentage of muscle. Those who are physiologically healthy usually engage in the minimal amount of exercise (or more) that is recommended according to the exercise guidelines for their region (if not more) and who follow a healthy balanced diet. Ellie's Story: In order to increase her physiological health, she was already a step in the right direction (minus the negative approach). Engaging in the recommended amount of physical activity per week (World Health Organization), eating a healthy and balanced diet and doing anything that will improve her body's function will improve her physiological health. This will make her feel better about herself and get a sense of satisfaction and accomplishment (impact on psychological health) and will increase her happiness. Figure 3. Universal icon of mental health Psychological Also known as mental health. According to the University of Western Australia (2014)[7], psychological health is “the overall state of mental wellbeing, incorporating emotions, stress, mental illness, sense of belonging, connectedness and life satisfaction”. Psychological health refers to an individual’s ability to cope with stresses in their life and the ability to manage their emotions. A psychologically healthy person can function optimally without any intrusion. Ellie's Story: Without changing her negative thoughts, she will not thrive. She first needs to admit she needs help. Then she must stop criticizing herself and she must accept herself for who she is. As she focuses on improving her mind, she will accept support from others (social health) and may realize that she is judging herself too harshly. She suffers from emotional eating, and therefore needs to learn to better cope with stress. She could take a class for stress management or find ways to increase her hedonic happiness (i.e. taking breaks from her stressful situation by doing something she enjoys). Social Social health is characterized by the economic and social conditions in which an individual finds themselves. It is the ability to have, make and keep friendships and relationships allowing them to further themselves in their careers, personal life etc. It is the ability to recognize social boundaries (what is considered right, what is considered wrong, what to do and what not to do). It also is stated to involve “the health of the society, or culture in which you live”. This can include your living situation, your income, insurance, any unhealthy relationships (i.e. presence of violence) etc. (Health and Wellness for families, n.d.)[8]. One who is considered to be “socially healthy” is gainfully employed, has a network of friends and family, has a support system, and is economically stable. Social health has a large impact on one's psychological and physical health. It has a major effect on emotions which can influence our behaviour and thoughts.(Health and Wellness for families, n.d.). Ellie's Story: She needs to reach out to her friends and family for support. Let them know how she feels, admit it and get help. A support system will increase her eudaimonic happiness because she will realize that she has connections with people; they care about her and they want to help her.

Theories of emotion

Emotional set point Also referred to as the adaptations theory, the emotional set point theory is one that theoreticize's that individuals have two emotional set points; one for positive emotionality (happiness) and one for negative emotionality (unhappiness set point) in which are independent from one another. It states that people have a biological (perhaps innate) set point that will regulate their happiness and their well-being. This regulation can be explained by individual differences in personality traits in which happiness is regulated by extraversion and unhappiness is regulated by neuroticism (Reeve, J., 2009). An emotional set point is a baseline level of subjective well-being and happiness/unhappiness levels in which individuals find themselves during a normal, non-eventful day. This being said, a high feeling of happiness following an emotion-exhilarating event is only temporary. Reeve, J. (2009) states that the “high” will only last a maximum of 2 months (depending on the event), and that a negative impact can only last about a week. A study conducted by Lucas, R., et al. (2003)[9] confirmed this notion. They tested this idea by conducting a longitudinal study in Germany examining the effects of marital transitions on life satisfaction on 24,000 individuals following major life events. They interviewed and distributed a variety of demographic questions and questions about their economic situations, as well as asked the participants to indicate their overall life satisfaction on a scale from 0-10. Their results suggested that, on average, individuals that got married were no happier before marriage than after. They state that: “people initially react strongly to both good and bad events, but then their emotional reactions dampen" (Lucas, R., et al., 2003), therefore confirming the validity of this theory. Therefore, there are two conclusions to this theory: you can either believe that we are somewhat limited to the amount of happiness we can have, or that “happiness is more a matter of how you feel during the events in your life rather than the events themselves. If you want to be happier than you are now, you should change your outlook” (Ghosh, S., 2010)[10].

Extraversion and happiness Figure 4. Richard Depue, 1996 (Lang, So., 1996) Director of the Laboratory of Neurobiology of Personality and Emotion at Cornell University. Worked on the relationship between dopamine and personality characteristics. As suggested in the previous theory, happiness and unhappiness are said to be related to the individual’s personality traits. We say that the personality characteristic that is related to happiness is extraversion. Reeve, J. (2009) suggests that there are three facets to extraversion: sociability, assertiveness and venturesomeness. He also describes that extraverts experience more positive moods and happiness than introverts simply because they are more sensitive to rewards, they “eagerly approach potentially rewarding situations” and they have greater activity coming from the behavioural activating system. The behavioural activating system (BAS) is a motivational biological system associated with energizing approach-oriented, goal-directed behaviour (Reeve, J., 2009), which would explain the extraverts normal social tendencies. Richard Depue, director of the Laboratory of Neurobiology of Personality and Emotion at Cornell University, argues that it is the different levels of dopamine / responsiveness to this hormone that would differentiate between happiness in extraverts versus introverts. He suggests that “the higher the level of dopamine, or the more responsive the brain is to dopamine, the more likely a person is to be sensitive to incentives and rewards. When our dopamine system is activated, we are more positive, excited and eager to go after goals or rewards […]” (Lang, S., 1996)[11]. He conducted a study in 1994 where he measured the level of extraversion in participants using personality tests. He then used an amphetamine, Ritalin, to activate the dopaminergic system. He then measured how much the system was activated by measuring the amount of prolactin hormone in the blood, as well as the changes in spontaneous eye blinks. His results found that high levels of dopamine highly correlate with extraversion (Depue, R., et al., 1994)[12]. In conclusion, we have to determine whether or not extraversion and introversion are set biological personality traits or if they can be developed over time. Therefore, happiness can in fact increase your social and psychological (hormone balance with increased dopamine) health. Ellie’s Story: Depending on her type of personality, Ellie can easily seek out any type of activity that will increase her dopamine levels in order to increase her overall happiness. She can do this by increasing her two types of happiness, which have been shown to increase each one of the types of health. If she is an introvert, a study conducted by Carol S. Dweck at Stanford University suggests that if you change your beliefs, you can change your personality (Dweck, C., 2008). See [[ https://web.stanford.edu/dept/psychology/cgi-bin/drupalm/system/files/cdweckpersonalitychanged.pdf | Can Personality be Changed? - Carol S. Dweck ]] for more information on this subject.

Happiness and a longer, healthier life We often hear the common phrase “happiness leads to a longer and healthier life”. A study conducted by Ed Diener proved that this is actually true (Yates, D., 2011). This professor from the University of Illinois concluded that, after reviewing eight different types of studies, “happy people tend to live longer and experience better health than their unhappy peers”. While examining the studies, he discovered that “anxiety, depression, a lack of enjoyment of daily activities and pessimism all are associated with higher rates of disease and a shorter lifespan” (Yates, D., 2011). He also discovered that an increase of cortisol (stress hormone) in the body lead to a higher degree of chronic diseases such as heart disease, as well as a higher prevalence of weak immune systems and death. Furthermore, positive emotions reduced the amount of daily stress and this promoted immune function. This was related to martial conflicts, as the individuals that had more martial conflicts and had higher levels of hostility were also associated with a poorer immune system (Diener, E., 2011)[13]. In conclusion, we can see that those who enjoy life the most are less likely to be affected negatively from the effects of disease and illness and therefore have a better physiological health. Ellie’s story: Since she is suffering from an eating disorder and pessimism, Ellie’s chances of developing a chronic illness later in life increases and her chances of living a long life decreases. If she were to try and change her outlook on life to a more optimistic view, with the help of therapy, her overall health would increase significantly. She likely enjoy life to a greater degree and could gain the benefits mentioned above from the Extraversion and Happiness theory to improve other types of health.

How do we measure happiness? There are many ways to test people’s happiness, whether it is to conduct a study yourself or to take a test online. Since personality is related to happiness, taking a personality test can help figure out what needs improvement in terms of extraversion, introversion, pessimism optimism etc. These are 3 common questionnaires that can be taken. | NEO Personality Inventory Scales free test (currently under improvement) | NEO Personality Inventory Scales (costs) | Big 5 Personality Test | Eysenk Personality Questionnaire Reeve, J. (2009) says : “Based on peoples scores on these questionnaires, psychologists can predict with confidence who will be excited, enthusiastic, and happy about being in potentially rewarding situations and psychologists can predict with confidence who will be inhibited, hesitant and anxious about being in potentially threatening situations”. There are also many questionnaires available online that allows you to track your happiness, measure your stress levels and more. These are easily found through google.

Changes in the brain and the body Firstly, it is important to note that happiness and unhappiness are not regulated by the same system in the brain (Klein, S., 2006) [14]. If you are experiencing one, it is still likely that you can experience the other. An example of this would be expecting to receive $100 from your mom for your birthday, but only getting 80$. You will still be happy that you got $80 but unhappy with the fact that you got 20$ less than you had hoped. Therefore, the positive and negative feelings have merged together. This being said, the positive feelings you receive are regulated by the behavioural activation system (BAS) and the negative feelings are regulated by the behavioural inhibition system (BIS) (Reeve, J., 2009). A study was released in 2011 confirming that individuals with high BAS activity were more responsive to positive emotions, and high BIS activity was related to negative and arousing emotions. This study determined this by examining corticol responses, psychophysiological conductance response, heart rate and electromyography (Balconi, M., Falbo, L., & Conte, V. (2011)[15]. To continue, it was learned that when someone is feeling happy, the left prefrontal cortex is more active, and in contrast the right side of the frontal lobe is more active when people feel sad (Breazeale, R., 2013, February 19)[16]. In terms of hormones, Dopamine and Serotonin play a large role in the regulation of emotions. Individuals that have brains that produce an abundance of dopamine, and who are highly sensitive to this, are said to be more motivated by incentives and derive more pleasure from rewards (and the opposite it true too) (Moment of Science, 2007)[17]. In terms of serotonin, it is said that those that have low levels of serotonin are more likely to develop depression, sleep disorders and addictions (HealthKeepers Magazine, 2012, April)[18]. Cortisol and Oxytocin play smaller roles in the regulation of emotion. High levels of cortisol (the stress hormone) will increase your chances of developing high blood pressure, obesity, diabetes etc. It is said that being happy produces healthy cortisol levels, and helps regulate it. Therefore, being happy regulates your health. Oxytocin (the cuddle hormone) is made in the hypothalamus and is stored and released by the brain’s pituitary gland. It decreases fear and anxiety, therefore improving your psychological health (Watson, n.d.)[19]. Ellie’s Story: Ron Breazele (2013, February 19th)suggests that: “ by learning what stimulates the left prefrontal cortex, we can encourage or even train people to be happier”. This is an approach we can take in order to help Ellie with the disorder. Not only does happiness influence the brain, but it also plays a role in terms of keeping your body functions working optimally. As discussed above, cortisol (the stress hormone) has an effect on your body's tendency to developing a chronic disease. But there is more. Dr.Mercola (2014, April 3)[20] in their article Why is happiness healthy states that positive thoughts and attitudes can actually strengthen your immune system, and decrease the sense of pain, decrease the chances of chronic diseases and provide stress relief. They also refer to a study that was conducted by Julia Boehm and Laura Kubzansky (2012)[21] which discovered that "happiness, optimism, life satisfaction and psychological attributes are associated with a lower risk of heart disease" (Mercola, 2014, April 3). This suggests that these positive attributes led to a better cardiovascular function, which is one of the causes of heart disease. Furthermore, in the article Pursuing happiness: The architecture of sustainable change (Lyubomirsky, S; Sheldon, K M; & Schkade, D. (2005))[22] the authors discuss that "subjective happiness may be integral to mental and physical health, happy people are more likely to evidence greater self-control and self-regulatory and coping abilities, a bolstered immune system, and even to live a longer life". This suggests that if you are better able to cope with stresses in your life, control certain situations to an optimal degree as well as self-regulate emotions for example, you will live a happier and healthier life, because you are able to control the release of the hormones involved in negative affect. Figure 5. Researchers suggest that the emotions expressed on social media have an impact on the emotions of the individuals reading the content posted online Some researchers have discovered that happiness can alter or trigger the activation of different genes. Mercola (2014, April 3) discovered that it is the different types of happiness (eudaimonic or hedonic) that will cause this. In example, individuals that expressed eudaimonic happiness were found to benefit from an increase in immune function due to personal control and circumstance. They state that "If they care about things beyond themselves, then everyday stresses will perhaps be less of concern". This suggests that the type of happiness you experience says something about your character. If you are able to achieve greater amounts of eudaimonic happiness, then you are less impacted by everyday stressors and this leads to gains in health. Other ways in which happiness can lead to health is related to social situations. Mercola (2014, April 3) states that emotional well-being increased with the amount of income an individual gained. Furthermore, experiences would make us happier than possessions. Older adults are more prone to negative responses than younger individuals simply because they tend to be able to regulate their emotions better, and are exposed to a lower amount of stress and negative emotions. It is also said that "emotions are known to be contagious among people in direct contact" (Mercola, 2014, April 3). This means that people tend to feed emotions off of their peers. If one person is unhappy at a party, the overall sense of mood will be more negative than if everyone were to be happy. This notion can be found on social media. Researchers of the article Happiness is viral, thanks to social media (MNT, 2014)[23] seems to think that social networks are an important factor in terms of improving mental and physical health because individuals are being affected by others emotional expressions.

Conclusion In conclusion, there are various ways in which happiness can affect your health. For the most part, being happy influences your health in a positive manner, in terms of hormone regulation, disease and illness prevention, social and physiological engagement, psychological stability and more. Happiness is also shown to be genetic and part of your personality but it does not mean that if you do not have the ideal components for such (such as being an extrovert) it does not mean that you will not be happy. What is important is that you find something you enjoy, incorporate it in a portion of every day and in the long run the psychological, social and even spiritual benefits will be incredible. Even smiling tricks your mind into feeling happy, so do it.

Test your knowledge

Point added for a correct answer:    Points for an incorrect answer: Ignore the questions' coefficients: 1 What was the name of the director of the Laboratory of Neurobiology of Personality and Emotion at Cornell University that contributed to dopamine levels and extraversion? Ron Breazele Robert Dupue Raina Shawn Rick Dean 2 Which of the following is not a theory of emotion mentioned in this chapter? Emotional Set Point Inverted-U Theory Extraversion and Happiness Happiness and a longer, healthier life 3 Which of the following is a type of health? Psychological Social Cultural a and b 4 What hormone is not involved in the regulation of emotion? Estrogen Serotonin Oxytocin Endorphins

See also

• Dopamine and emotion
• Serotonin and emotion
• Cortisol - Stress and emotional health
• Oxytocin and emotion
• [[[Wikipedia:Salutogenesis||Salutogenesis - another theory to consider]]]

References

Balconi, M., Falbo, L., & Conte, V. (2011). BIS and BAS correlates with psychophysiological and cortical response systems during aversive and appetitive emotional stimuli processing. Motivation and Emotion,36(2), 218-231. Retrieved October 15, 2014, from http://link.springer.com/article/10.1007/s11031-011-9244-7#page-1

Boehm, J. K., & Kubzansky, L. D. (2012). The Heart's Content: The Association Between Positive Psychological Well-Being and Cardiovascular Health. Psychological Bulletin, 138(4), 655-691. doi:10.1037/a0027448

Breazeale, R. (2013, February 19) The Role of the Brain in Happiness. Retrieved October 15,2014, from http://www.psychologytoday.com/blog/in-the-face-adversity/201302/the-role-the-brain-in-happiness

Depue, R., Luciana, M., Arbisi, P., Collins, P., & Leon, P. (1994). Dopamine and the Structure of Personality : Relation of Agonist-Induced Dopamine Activity to positive emotionality.Journal of Personality and Social Psychology, 67(3), 485-498. Retrieved from http://www-psych.stanford.edu/~knutson/fop/depue94.pdf

Diener, E. (2011). Happy People Live Longer: Subjective Well-Being Contributes to Health and Longevity. Applied Psychology : Health and Well-Being, 3(1), 1-43. Retrieved from http://internal.psychology.illinois.edu/~ediener/Documents/Diener-Chan_2011.pdf

Dweck, C. (2008). Can Personality Be Changed? The Role Of Beliefs In Personality And Change. Current Directions in Psychological Science, 17(6), 391-394. Retrieved October 15, 2014 from https://web.stanford.edu/dept/psychology/cgi-bin/drupalm/system/files/cdweckpersonalitychanged.pdf

Ghosh, S. (2010), Physiology of Emotion [Slideshare]. Retrieved from http://www.slideshare.net/shaan_47/physiology-of-emotion-5651975

Grohol, J. M. (2013, January 30). All About Mood Swings. Retrieved from http://psychcentral.com/lib/all-about-mood-swings/000920

Health and Wellness for families. (n.d.). Social Health. Retrieved from http://www.healthandwellnessforfamilies.com/health-wellness/social-health/

HealthKeepers Magazine. (2012, April). Serotonin: The Happiness Hormone. Retrieved from http://www.healthkeepersmagazine.com/article.php?id=47

Kemsley, T. (2013, July 30). Human Body Distinguishes Between 'Hedonic' and 'Eudaimonic' Happiness on Molecular Level. Retrieved from http://www.natureworldnews.com/articles/3242/20130730/human-body-distinguishes-between-hedonic-eudaimonic-happiness-molecular-level.htm

Klein, S. (2006). The science of happiness: How our brains make us happy--and what we can do to get happier. New York: Marlowe. Retrieved from http://books.google.com.au/books?id=UFuvGJ9_LT8C&printsec=frontcover&source=gbs_ViewAPI&redir_esc=y#v=onepage&q&f=false

Lang, S. (1996). Dopamine linked to a personality trait and happiness. Retrieved from http://www.news.cornell.edu/stories/1996/10/dopamine-linked-personality-trait-and-happiness

Lucas, R., Clark, A., Georgellis, Y., & Diener, E. (2003). Reexamining adaptation and the set point model of happiness: Reactions to changes in marital status. Journal of Personality & Social Psychology, 84(3), 527-539. Retrieved from http://www.apa.org/pubs/journals/releases/psp-843527.pdf

Lyubomirsky, S; Sheldon, K M; & Schkade, D. (2005). Pursuing happiness: The architecture of sustainable change. Review of General Psychology, 9(2), 111 - 131. UC Riverside: Retrieved from: http://escholarship.org/uc/item/4v03h9gv

Mercola. (2014, April 3). Happiness May Influence Your Immune Function and More. Retrieved from http://articles.mercola.com/sites/articles/archive/2014/04/03/happiness-improves-health.aspx

Moment of Science. (2007, January 22). High on Dopamine. Retrieved October 15, 2014, from http://indianapublicmedia.org/amomentofscience/high-on-dopamine/

MNT. (2014). Happiness is viral, thanks to social media. Retrieved from http://www.medicalnewstoday.com/articles/274017.php

My Fitness Pal. (2012, November 3). What do YOU consider healthy? Retrieved from http://www.myfitnesspal.com/topics/show/787371-what-do-you-consider-healthy

Reeve, J. (2009). Nature of Emotion : Five Perennial Questions. In Understanding motivation and emotion (5th ed., pp. 322-327). Danvers, MA: John Wiley & Sons.

The Meanings of Health and its Promotion. (2006). Retrieved from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2080455/

The Science Channel. (2011). What are some of the physical effects of happiness? - Curiosity. Retrieved from http://curiosity.discovery.com/question/physical-effects-happiness

University of Western Australia. (2014, October 1). Psychological health : Safety, Health and Wellbeing : The University of Western Australia. Retrieved from http://www.safety.uwa.edu.au/health-wellbeing/health/psychological

Watson, D. (n.d.). The Effects of Happiness on Hormone Levels. Retrieved from http://www.ehow.com/list_7508621_effects-happiness-hormone-levels.html

World Health Organization. (2003). WHO definition of Health. Retrieved from http://www.who.int/about/definition/en/print.html

External links

• Functional polymorphism (5-HTTLPR) in the serotonin transporter gene is associated with subjective well-being: evidence from a US nationally representative sample
• The Science of Happiness: How Our Brains Make Us Happy--and What We Can Do To Get Happier