The better connected are one’s friends and family, the more likely one will attain happiness in the future
The emotional state of a person’s social relationships is more important to one’s own emotional state than the total number of those relationships
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Figure 1 also suggests a relation between network centrality and happiness: people at the core of their local networks seem more likely to be happy, while those on the periphery seem more likely to be unhappy. ? We tested this by computing eigenvector centrality measures for each subject. Generalised estimating equation regressions show that ego centrality is significantly associated with improved future happiness: a 2 SD increase in centrality (from low to medium or medium to high) increases the probability of being happy at the next examination by 14% (1% to 29%, P=0.03). Moreover, the relation between centrality and future happiness remained significant even when we controlled for age, education, and the total number of family and non-family alters. Thus, it is not only the number of direct ties (at one degree of separation) but also the number of indirect ties (at higher degrees of separation) that influence future happiness. Conversely, happiness itself does not increase a person’s centrality at subsequent time points (see appendix on bmj). That is, network centrality leads to happiness rather than the other way around.
Figure 3 ? shows the positive association between the total number of happy alters and ego’s future probability of being happy in the raw data. To test the relation more rigorously, we specified generalised estimating equation regression models of ego happiness with the number of happy and unhappy alters in the previous exam as key predictors. The relation is highly significant, with each happy alter increasing the probability the ego is happy by about 9% (P=0.001), and each unhappy alter decreasing it by 7% (P=0.004). Hence, on average, having additional social contacts is helpful to ego’s happiness only if the extra social contacts are happy themselves. We also evaluated the simultaneous effect of total number of alters (whether happy or unhappy) and the fraction of alters who are happy. These models show that happy alters consistently influence ego happiness more than unhappy alters, and only the total number of happy alters remains significant in all specifications (see appendix on bmj). In other words, the number of happy friends seems to have a more reliable effect on ego happiness than the number of unhappy friends. Thus, the social network effect of happiness is multiplicative https://hookupdate.net/it/parship-review/ and asymmetric. Each additional happy alter increases the likelihood of happiness, but each additional unhappy alter has little or no effect.
Fig 3 Happy alters in Framingham social network. Mean probabilities observed in raw data with standard errors. Ego happiness in exams 6 and 7 (dichotomised between those who are maximally happy and everyone else) is positively associated with number of happy alters in previous exam. Generalised estimating equation regression models in appendix (see bmj) confirm relation is strongly significant, even with numerous controls
The emotional state of a person’s social relationships is more important to one’s own emotional state than the total number of those relationships
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We examined the direct ties and individual level determinants of ego happiness in more detail. The principal determinant of a person’s happiness was their previous happiness; individuals who were happy at one wave were roughly three times more likely than unhappy people to be happy at the subsequent observation.
Age, sex, and education had effects consistent with previous research, with women being less happy then men and educated people being slightly happier (see appendix on bmj)
Our main interest was the impact on an ego of the happiness of others. Figure 4 shows the results of generalised estimating equation models that distinguish effects for friends, spouses, siblings, coworkers, and neighbours. ? We can use these results to estimate what would happen to the happiness of the ego if the alter were “switched” from being unhappy to being happy-that is, if the alters “become” happy. “Nearby” friends (who live within a mile (1.6 km)) and who become happy increase the probability ego is happy by 25% (1% to 57%). “Distant” friends (who live more than a mile away) have no significant effect on ego. Among friends, we can distinguish additional possibilities; as each person was asked to name a friend, and not all of these nominations were reciprocated, we have ego perceived friends (denoted “friends”), “alter perceived friends” (alter named ego as a friend, but not vice versa) and “mutual friends” (ego and alter nominated each other). Nearby mutual friends have a stronger effect than nearby ego perceived friends; when they become happy it increases the probability ego will be happy by 63% (12% to 148%). In contrast, the influence of nearby alter perceived friends is much weaker and not significant (12%, ?13% to 47%). If the associations in the social network were merely caused by confounding, these effect sizes for different types of friendships should be more similar. That is, if some third factor were explaining both ego and alter happiness, it should not respect the directionality of the tie.
