Fit For Happiness

Read a book (and be an introvert).

Posted Apr 30, 2016

J. Krueger
Source: J. Krueger

Wine is constant proof that God loves us and loves to see us happy. ~ Ben Franklin

If you always do what interests you, at least one person is pleased. ~ Katherine Hepburn

A most interesting branch of happiness research is that which involves tips for us to make ourselves happier. Scientific self-help as it were. One important question is whether the way we spend our discretionary income can lift our happiness in the moment or perhaps even our general life satisfaction. There is now good evidence for the idea that, overall, we are happier when spending money to buy experiences instead of things, when buying for others instead of ourselves, and when making many small expenditures instead of a few large ones.

Once general effects of this kind are well established, more fine-grained questions can be asked. Might our purchases be most uplifting, for example, when they reflect our own personality? The short answer would have to be: yes! Inasmuch as personality involves a profile of personal preferences, and inasmuch as preferences (wants) are linked to needs (gratification), then it would have to be so. And if so, the personality-fit hypothesis of happiness should not be hard to confirm. It appears, actually, to be somewhat tautologically true.

Enter Matz et al. (2016) who report their findings from one big-data study and one experiment in Psychological Science. They looked at material purchases for the self, thereby making it harder to find anything because we already know that such investments only affect happiness only mildly (contrary to my suggested tautological truth in the previous paragraph). Matz's methods are impressive, though, making it likely that they would find something if there was something to be found. Study 1 involved data from 625 individuals and a total of 76,863 purchase transactions. These data came from a survey logged through a British bank and they, the data, are big indeed. The authors then categorized the purchases (e.g., sports, supermarkets, travel) and had each category’s personality rated by an independent sample of judges along the “Big 5” trait dimensions of Extraversion, Agreeableness, Conscientiousness, Neuroticism, and Openness to new experiences. The 625 buyers also rated their own personalities, enabling the researchers to compute a fit score (a Euclidian distance) between person and purchase, and then to correlate this fit score with a measure of life satisfaction.

The first finding is that people spend to fit. Extraverts spend more on sports, travel, and take-out food than others do, and conscientious individuals spend more on stationery and subscriptions (again, why wouldn't they?). For the other three traits, the data are less clear. Overall, personality predicts purchases, but the effect is small (more on this in a minute). The second finding is that the person-purchase fit predicts life satisfaction. Now, if the fit effect is small to begin with, it can't be a strong predictor of the outcome of interest (happiness). And it isn’t. The authors report regression weights, the confidence intervals of these weights, test statistics (t) of significance, and the probabilities of these statistics under the null hypothesis, that is, under the assumption that there is no effect. They do not report, however, an easily interpretable effect size measure. So I computed a correlation coefficient that would be associated with a t value of 2.07 and 600 degrees of freedom. The result is r = .04. This is a very small correlation. It might be ‘real’ in the sense of being replicable, but it gives only very modest support to the categorical claim that spending to fit your personality will make you happy (as claimed by the title of the paper).

J. Krueger
My friend Billy with beer and book: Nietzsche's 'Beyond good and evil.'
Source: J. Krueger

The authors then did what careful researchers do; they sought to capture the phenomenon of interest in a controlled experiment. The method was  elegant. They gave vouchers to extraverts and introverts to either buy a drink or a book. Along the way, participants repeatedly completed a measure of positive and negative mood so that the researchers could study deviations from the mood baseline. The results showed that introverts who had bought books enjoyed mood lifts. The three other conditions (introverts buying a drink or extraverts buying anything) did not differ from baseline. The authors focus on the statistical interaction between personality (intro vs. extro) and purchase (book vs. drink). When the mood baseline is considered as well, however (as it should be if we are interested in changes in happiness), we are left with one significant effect (and we don’t have the p value for that one) out of four. This is weak medicine, but it may be enough, at least for us introverts. Let’s read that book, or better yet, give it to someone else. -- or: go to a bar and read a book there, drink in hand.My friend Billy (see photo) is a card-carrying extravert who also enjoys a quality book, so I fixed him up with both. That made him happy and me even happier because I purchased for a

friend. 

J. Krueger
Source: J. Krueger

Post-blog: The authors (Matz and colleagues) cautiously suggest that the personality-purchase fit effect on happiness is a win-win-win in a world of online advertising and shopping. Sellers learn your preferences and nudge you to buy more of what you already have. This may seem like a good idea, but let us acknowledge that it is highly conservative and ultimately constraining. Gradually, your fit will turn into a corset and ultimately a straightjacket. Remember that the other secret to happiness is not fit but unfit. New experiences want to be had. And novelty requires (by definition) new and different purchases. As well, you probably know that person-tailored online advertising can be quite stupid. I recently bought an "e-bag," and now I am being bombarded by e-bag ads. How many bags do they think I need?

J. Krueger
Source: J. Krueger

Traumazon: The situation is a little different when Amazon invades my Facebook stream telling me that they "hand-picked a few items" for me. Indeed, I looked at that book on decision-making and I decided not to buy it, which Amazon knows. They seem to think that they can change my mind by hand-picking an already discarded item. The use of the phrase "hand-picked" is so humanizing. They really care! How can I resist? The decision is made.

Matz, S. C., Gladstone, J. J., & Stillwell, D. (2016). Money buys happiness when spending fits your personality. Psychological Science. Online first, April 7.