Which factors influence happiness?

Being happy is one of the most fundamental goals in life. But, how to achieve happiness? Research has shown that changing life circumstances (for instance marital status, career, and income) is not the most successful path to greater happiness. Instead, simple cognitive and behavioral strategies that one can employ in daily life, have been found to improve happiness reliably. The fulfillment of basic psychological needs (autonomy, competence, and relatedness) appear to be much better predictors of happiness. A large share of happiness may be under people's own control through the activities they choose and how they respond to situations in their life.

Is happiness genetically determined?

Although prior research from twin studies suggested that happiness levels are strongly influenced by genetics, more recent research shows that genetic influences on happiness are far weaker than originally thought. Instead, environmental influences appear to explain a large share of individual differences in happiness. In addition, genetics and environment seem to act in a dynamic process, so even genetic predispositions are not deterministic.

How can differences over time in happiness levels be explained?

While individual differences and environmental influences combined explain a (large) share of the happiness puzzle, there remains a gap in the explained variance. In particular, people's happiness levels have been found to change over time. Yet, research has shown that even substantial changes in people's life circumstances (for instance marriage, divorce, a new job) do not lead to such sustained shifts in happiness. In this book chapter, the authors argue that these observed changes can be explained partly by the deliberate ways people choose to think and behave in their daily lives.

How can well-being be increased?

One way to increase the level of happiness is by means of positive activity interventions (PAIs). PAIs involve simple, self-administered cognitive behavioral strategies. These strategies are developed to mirror the thoughts and behaviors of naturally happy people, and subsequently, improve the happiness of the person performing them. Examples are: writing letters of gratitude, counting one's blessings, practicing optimism, performing acts of kindness, using one's strengths in a new way, affirming one's most important values, and mediating on positive feelings towards self and others. These activities are similar in the sense that they all are relatively brief, self-administered, and non-stigmatizing exercises that promotive positive feelings, thoughts and/or behaviors, rather that directly aiming to fix negative feelings, thoughts, and/or behaviors.

An increasing body of research is showing that happiness-increasing strategies simulate increases in well-being. A popular cited meta-analysis of 51 PAIs showed that positive interventions significantly increase well being (overall mean r = .29) and decrease depressive symptoms (overall mean r = .31).

Now that is has been established that PAIs can increase well-being, current and future research should focus on questions that involve understanding the mechanisms underlying the success of happiness-increasing interventions. In other words, by now we know that they work, but we also would like to know how they work. How, why, what, when, and who is the success of PAIs? Or, in more formal terms, what are the moderators and mediators underlying the efficacy of happiness-boosting strategies? Fortunately, a great body of research has already looked into these underlying mechanisms. In this chapter, an overview is provided of what has already been found, as well as what remains to be examined.

What are the underlying mechanisms of positivity activity interventions (PAIs)?

Mediators of PAIs

According to Lyobomirsky and Layous (in press), prompting people to perform positive activities leads them to have: (1) more positive emotions; (2) positive thoughts; (3) positive behaviors; and (4) greater satisfaction of basic psychological needs. This, in turn, may lead to increased well-being. These four mediators are summarized in a model called the positive activity model. Recent studies provide preliminary evidence for each of the four proposed mediators. Yet, more research is needed to test this model and to further examine the role of these four mediators.

Intervention characteristics

Next, the effectiveness of PAIS is influenced by several features of the intervention, such as their timing, dosage, and variety. Preliminary research has suggested that timing and dosage matter in PAIS, just as they do in for example medication. The length of the intervention may also influence the effectiveness: the longer the intervention, the greater the increase to well-being. The authors predict, in this case, a curvilinear relationship between increases in well-being and the length of the intervention. If the same activity is performed without any variation, people may become bored as some points, and experience less of the initial boost in happiness as they once experienced. Indeed, research has shown that variety in thoughts and behaviors is inherently motivating and rewarding. Hence, variety in positive activity interventions is needed to increase the success of the intervention.

Personal and cultural characteristics

The mediators and moderators that are discussed above, all have shown positive overall effects on increasing well-being. However, there is also research that looked beyond these simple averages, and revealed that PAIS work better for some individuals than others. Two important components of the individual success of PAIs are: the participant's motivation to engage in the target activity, and the participants belief that the activity could work to enhance well-being. A third influential personal characteristic, related to motivation and belief, is effort: people who are willing to put more effort in a positive activity, are more successful that peers who are putting less effort in. A fourth factor is social support (the perceived or actual support one receives from at least one other individual). Social support has been found to have a direct effect on well-being as well as a buffering effect on stress. Fifth, culture matters. The values that are relevant to the culture with which one identifies are likely to influence how the individual performs positive activities and how effective these activities may be. Different cultures conceive happiness in different ways. Yet, few studies have considered culture. Therefore, more research is needed to examine the role of culture on the efficacy of positive activities. Sixth, age matters. It appears that certain age groups benefit more from PAIs that other age groups do. For instance, a meta-analysis has shown that older participants (36-59 years old) benefit more from these positive activities that younger participants (18-35 years old) do. However, there were few studies at the ends of the age range. Recent evidence is emerging that shows that positive activities can benefit youth populations, yet more research into the effectiveness of PAIs for (even younger) children is needed.

Further, research suggests that a certain baseline level of well-being is needed before one is able to benefit from the positive activities. To date, research on how PAIs affect depressed individuals is limited and the results are mixed.  

Lastly, although this has not been widely studied yet, recent studies stress the importance of person-activity fit. This is denoted by the French phrase "à chacun son goût" which means "to each his own taste". In other words, certain positive activities may work better for certain types of people. For instance, highly extraverted people may benefit more from activities that encourage them to interact with other people. Whereas religious individuals may benefit more from activities with a spiritual component. Yet, a recent study has also shown that the most fitting activity employed by users of an iPhone application was not necessarily the most effective one. This suggests that person-activity fit may not be the sole criterion of effectiveness.

How long does the effect of a PAI last?

A six-week PAI is not expected to fuel endless amounts of happiness. But, how long does the effect last? There is no decisive answer to this question. Yet, the authors predict that positive activities, ideally, trigger people to experience an upward spiral of positive emotions, thoughts, and behaviors, which can serve as a catalyst for lasting positive change. This upward trajectory may not be activated right away, and requires sustained practice.

Can one be too happy?

Some studies have shown that a too high degree of happiness (including (hypo)mania), may have maladaptive outcomes. Yet, the authors of this book chapter do not believe that the goal of PAIs is to galvanize an upward trajectory of happiness without limit.