Middle-aged not miserable, just too busy to answer surveys

I have read several times that there is evidence of a U-curve in happiness over an individual’s life. People are happy in their youth, and happy again after retirement, but suffer from a serious malaise in between as they grapple with their finances, careers and family life. Seeing as how I’m about to embark on this part of my life, that isn’t a particularly appealing idea! Today I was glad to find some evidence that the U-curve is just a statistical illusion. Australian economists Paul Frijters and Tony Beatton have analysed large panel data sets from Australia (n>10,000), the UK (n>25,000) and Germany (n>20,000) and produced the following trajectory for happiness as people age:

Happiness is nearly flat from 20 through 50. Frijter’s explanation for the disagreement with the existing literature is that,

previous studies severely underestimated the degree to which miserable people in middle-age were over-represented in these datasets: happy people in middle age are busy and don’t have time to participate in lengthy questionnaires, leading previous studies to erroneously think there was a huge degree of unhappiness in middle-age. When you actually follow people over time, no such ‘middle-age blues pattern’ can be found, at least not in Australia or the UK and only to a mild degree in Germany. … we found that there were severe data problems in Germany, with only quite miserable people in middle-age prepared to partake in the sample and respondents becoming markedly more honest (and miserable) as they answered the happiness questions year after year.

Those of us with active lives need not fear! There are familiar selection problems later in life as well. Unhappy people do not live as long, and may become less able or willing to answer surveys than their healthy and cheerful counterparts. By tracking the same participants for 10 years or more, Frijters claims to have “dealt with both issues,” presumably suing their initial responses to by forecast their missing responses later in life. Some day I should choose carefully where I decide to retire and perhaps return to my homeland: “life in old age is clearly relatively better in Australia than the UK, perchance because of the better weather, more generous public pensions, and more space.”

Another, more depressing, paper on happiness recently caught my attention. Probably due to its early use of twins to investigate the causes of happiness it has landed over 900 citations, despite a limited sample of separated twins. It finds a remarkably high correlation between the happiness of twins who share all of their genes, but very little correlation for twins who share half of their genes:

Happiness or subjective wellbeing was measured on a birth-record based sample of several thousand middle-aged twins using the Well Being (WB) scale of the Multidimensional Personality Questionnaire (MPQ). Neither socioeconomic status (SES), educational attainment, family income, marital status, nor an indicant of religious commitment could account for more than about 3% of the variance in WB. From 44% to 53% of the variance in WB, however, is associated with genetic variation. Based on the retest of smaller samples of twins after intervals of 4.5 and 10 years, we estimate that the heritability of the stable component of subjective wellbeing approaches 80%.

…

For the 48 DZ [fraternal] pairs, this cross-twin, cross-time correlation for WB was essentially zero (.07) while, for the 79 MZ [identical] pairs, it equaled .40, or 80% of the retest correlation of .50. The MZ data suggest that the stable component of wellbeing (i.e., trait-happiness) is largely determined genetically. The negligible DZ correlation suggests that this stable and heritable component of happiness is an emergenic trait (Lykken, 1982; Lykken, Bouchard, McGue, & Tellegen, 1992), that is, a trait that is determined by a configural rather than an additive function of components. Emergenic traits, although determined in part genetically, do not tend to run in families as do traits that are polygenic-additive.

A similar result was reported in an earlier study of 217 MZ and 114 DZ pairs of middle-aged Minnesota Registry twins, plus 44 MZ and 27 DZ pairs who were separated in infancy and reared apart (Tellegen, et al., 1988). The best estimate of the heritability of WB in that study was .48 (± .08) and, as was true here, a model involving only additive genetic effects did not fit the data.

…

Myers and Diener suggested that people who enjoy close personal relationships, who become absorbed in their work, and who set themselves achievable goals and move toward them with determination are happier on the whole than people who do not. We agree, but we question the direction of the causal arrow. We know that when people with bipolar mood disored are depressed, they tend to avoid intimate encounters or new experiences and tend to brood upon depressing thoughts rather than concetrating on their work. Then, when their moods swings toward elation, these same people tend to do the things that happy people do. This is undoubtedly a James-Lange feedback effect: Dysfunctional behavior exacerbates depression, whereas the things happy people do enhance their happiness. We argue, however, that the impetus is greater from mood to behavior than in the reverse direction. It may be that trying to be happier is as futile as trying to be taller and therefore is counterproductive. (HT Jim Savage)

My impression – which I would be happy to have corrected – is that later research finds a smaller, but still significant impact of genetics on happiness.

That result brought to mind something John Stuart Mill wrote in his autobiography: “I am now convinced that no great improvements in the lot of mankind are possible until a great change takes place in the fundamental constitution of their modes of thought.” I imagine Mill had education and cultural shifts in mind, and the consistent difference in reported subjective wellbeing between South America and Eastern Europe show culture makes a difference. But if genetics plays such a large and limiting role, the only way to drastically alter our ‘modes of thought’ will require that we learn how to tinker with our minds directly.