Friday, 10 June 2016

Alcohol, momentary happiness, and life satisfaction

Last month, Honor Whiteman reported in Medical News Today on this study (sorry I don't see an ungated version anywhere, but it looks like the article is open access anyway) by Ben Baumberg Geiger (University of Kent) and George MacKerron (University of Sussex), published in Social Science & Medicine. Whiteman writes:
Study leader Dr. Ben Bamburg [sic] Geiger, from the University of Kent in the United Kingdom, found that while drinking alcohol makes us momentarily happy, it fails to offer long-term life satisfaction and well-being.
This sounded like an interesting study, so I sought it out. The authors analysed two U.K. data sources to investigate the relationship between wellbeing and alcohol consumption. I'll start with their second analysis, which used data on momentary happiness ('Mappiness' - see here). The authors describe the data as follows:
Rather than the traditional method of recruiting a sample and providing them with a diary or computer, Mappiness uses a sample of existing iPhone users who chose to download the Mappiness app. Users are then beeped at regular but random moments (the default is twice/day between 08:00-22:00), giving them a brief questionnaire about how happy they are, who they are with, and what they were doing just prior to their response...
After excluding non-UK responses, the total sample here contains 2 million individual responses, collected from 31,302 individual users across 2010-2013... Given the self-selection into the sample and the restriction to iPhone users, it is unsurprising that the sample is unrepresentative of the UK population: participants are more likely to be young (two-thirds are under 35) and wealthy (median income is £48,000, almost twice the UK median)...
The last point is important, but we won't worry about that for now. Importantly, the dataset is large and contains multiple measurements for each person, both when they are drinking and when they are not. The longitudinal nature of the data allows them to use fixed effects models, which essentially strip out the effects of anything specific to the individuals that doesn't change over time.

They find that momentary happiness is greater when individuals are drinking, by about 3.6 points (on a 0-100 scale). It's hard to evaluate whether that is a large effect because they don't tell us the descriptive statistics (mean, standard deviation, etc.) for the happiness scale, either in the text or in the online appendix, but we know it is statistically significant (and probably small). They are largely able to rule out reverse causation (people drink when they feel happier), because even when controlling for happiness earlier in the same day, drinking is associated with 3.3 points higher happiness. So, within this sample (noting its' unrepresentativeness), drinking is associated with higher happiness in the moment.

The first analysis took a more long-term view. They used longitudinal data from the British Cohort Study 1970 (BCS70), which included 17,000 babies born in the same week in 1970 in the U.K. The authors used data from the 1999/2000, 2004, and 2012 waves of the study, when the study participants were aged 30, 34, and 42 respectively. They essentially looked at the effect of alcohol consumption on life satisfaction (measured on a 0-10 scale). They found (emphasis is theirs):
In the unadjusted FE model, increases in drinking beyond 1 unit/wk are associated with reduced life satisfaction... In the final models that control for both unobserved time-invariant (via fixed effects) and observed time-varying factors (via controls), we see a similar pattern, but this is weaker and not statistically significant...
In other words, alcohol consumption is not associated with life satisfaction (and they also found that problem drinking (measured by CAGE) was associated with lower life satisfaction). So, this study is telling us that while alcohol consumption might be associated with increased happiness in the moment, it doesn't increase longer-term life satisfaction (and reduces life satisfaction for problem drinkers).

It's hard to say what to take away from this study. The two samples, while both from the U.K., are not directly comparable. The Mappiness sample is both younger and richer than the BCS70 sample. So the Mappiness results don't tell us whether poorer people experience the same gains in momentary happiness (and I don't have a prior as to the likelihood of the effects being the same or different). The difference in age between the samples may be important too. The authors found in supplementary analyses that the effects on momentary happiness were largest among the youngest respondents. Maybe the positive momentary happiness effects spill over into life satisfaction, but because the increases in momentary happiness only occur for young people, we don't see any positive impact on the BCS70 sample only because they are too old to experience the positive gains. It's hard to say - there's definitely room for more research like this.

And before we rush out proclaiming that all is well with alcohol because it increases momentary happiness, we need to remember that promoting people's momentary happiness may not be consistent with promoting people's long-term wellbeing. I'm sure we can all think of things we have done that made us happy in the moment, but which we later regretted. It's also worth noting that there is not necessarily any expectation that momentary happiness and longer-term life satisfaction be closely correlated (see for example Daniel Kahneman on the difference between experienced happiness and life satisfaction).

Overall, understanding the impacts of alcohol use on wellbeing is important, and under-studied. The authors note in their conclusion:
Policymakers currently have a choice between overestimating the wellbeing gains of alcohol policies (by valuing alcohol's negative wellbeing impacts and ignoring positive impacts), underestimating them (by using implausibly naive versions of the consumer surplus approach), or ignoring them altogether. Yet policymakers and the public are often concerned about the wellbeing impacts of alcohol policies - and in the absence of any considered debate from academic researchers, they will be left clutching at the naive approaches used by those outside of academia.
Which is why rubbish research like this gains a disproportionate share of attention. We can do better.

[HT: Marginal Revolution]

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