Smarter people are happier, says new analysis involving 80,000 participants, but only a bit

By Christian Jarrett

“happiness in intelligent people is the rarest thing I know” Ernest Hemingway

A lot of us would like to be smarter and happier, but does one lead to the other? Folk wisdom suggests not: old sayings tell us that “ignorance is bliss” and that “only a fool can be happy”. What does the psychology literature say? A new meta-analysis in the Journal of Vocational Behaviour has combined the results from dozens of previous studies involving many tens of thousands of participants and, contrary to the received wisdom, it concludes that higher intelligence actually does correlate with greater happiness (or “life satisfaction”) and job satisfaction, but only weakly.

Erik Gonzalez-Mulé at Indiana University and his colleagues sifted the literature, identifying relevant papers, published and unpublished, going back to 1980. Combining the results from 33 papers involving nearly 50,000 participants, they found that intelligence (or what they called “general mental ability”) had a weak but statistically non-significant positive correlation with life satisfaction, and a modest, statistically significant positive correlation with job satisfaction.

They found further evidence for the apparent benefits of higher intelligence for life satisfaction by factoring in the influence of “job complexity” (greater complexity meaning a job with more variety, skill demands and autonomy) and job income, two factors that are themselves correlated with greater happiness. This showed that higher intelligence has indirect links with greater happiness because more intelligent people tend to earn more, but especially because they tend to have more complex jobs, which presumably are more rewarding.

According to 38 studies involving nearly 30,000 participants, higher intelligence also had indirect links with job satisfaction by virtue of the fact that it correlated with job complexity and income. But this is psychology, so of course there’s a twist that somewhat supports the folk wisdom about intelligent people rarely being happy. When the researchers held job complexity and income constant in their analysis, they found that higher intelligence actually correlated with less job satisfaction. Put differently, if you imagine a range of people at a given level of job complexity and income, those with higher intelligence will tend to be less happy with their jobs. This makes intuitive sense if you consider that smarter people will be more likely than others to experience boredom and frustration at jobs that are not challenging enough.

The great strength of meta-analyses like this one is in the huge amounts of data that they can draw on. But the new study also has some obvious limitations: some of the data is decades-old and may not be relevant to today’s world. Also, this is cross-sectional data which can’t convincingly address whether intelligence is causing changes in life and job satisfaction, nor how such processes may unfold over time.

Are smarter people happier? Meta-analyses of the relationships between general mental ability and job and life satisfaction

Image by Orren Jack Turner, via Wikipedia

Christian Jarrett (@Psych_Writer) is Editor of BPS Research Digest

Toilet psychology: Why do men wash their hands less than women?

The spread of super-resistant bacteria means the science of hand-washing behaviour has become a serious business. Psychologists have stepped up to the plate. Bowl, I should say. By hiding in toilet cubicles for a new study, they’ve observed how long people spend using the loo, and how long they wash their hands for afterwards. That men usually wash their hands less conscientiously than women is a well-established finding. Thomas Berry and his colleagues wanted to find out more about the reasons for this gender difference.

For one day, between 10am and 4pm, a male researcher secreted himself inside one of three cubicles in a gents toilet facility at a US University. For optimal observational purposes he chose the cubicle adjacent to a row of three urinals. Nearby, in a similarly designed female toilet facility, a single female researcher positioned herself in one of the three cubicles available. Don’t worry, both researchers were provided with a “customised wooden bench” for comfort.

They were also equipped with stopwatches. The researchers used an “unobtrusive sight procedure” – that is, they spied on other visitors to the lavatories using the gaps beneath and by the side of the cubicle doors (for some reason, US toilet cubicles always have a gap of about a centimetre either side of the door). The researchers also used an “acoustic procedure”. That is, they listened to the visitors’ actions. The study authors explained:

“… research assistants recorded the facility [urinal or cubicle], and then started a stopwatch when the patron’s feet stood relatively still. For the men, the research assistants also recorded the orientation of the feet to gauge the patron’s use of the commode (i.e. as a commode or a urinal). When research assistants heard the flushing of the patron’s commode or urinal the stopwatch was turned off … and the duration of the restroom event was recorded.”

Similar procedures were followed for recording each visitor’s “hand washing event” if there was one. A clever twist was that for part of the study, the researchers put “out-of-order” signs over the men’s urinals. This was to see how much they’d hand wash if they were forced to urinate in a cubicle, rather than at a urinal.

The psychologists managed to observe the toilet behaviour of 34 women using cubicles; 32 men who used a cubicle to defecate; 40 men who had no choice but to use the cubicles for urinating (because of the out-of-order signs); and 64 men who used a urinal. The bare statistics show that the hand-washing rates for these four groups were 91 per cent, 87.5 per cent, 75 per cent and 59.4 per cent, respectively.

The difference in hand washing rates between women using a cubicle and men using a cubicle (for defecating) was not statistically significant. In contrast, both women using a cubicle, and men using a cubicle (for defecating), showed significantly higher hand-washing rates than men who used a urinal.

The data are somewhat compromised because, as the researchers delicately put it – the women’s “facility use is a constant (i.e., commode) and their behaviour (urination, defecation, or menstrual care) is confounded within the one environment.” However, taken together, the results suggest that the reason men wash their hands less than women overall, is not because of gender norms (i.e. men are less bothered about being clean), but because of the differences in the toilet environment and toilet behaviour for men and women. In fact, after using a toilet cubicle to defecate, men tended to wash their hands for longer than women (but remember we don’t know what the women had been doing).

This raises a question: do men wash their hands more thoroughly after using a toilet cubicle because of what they’ve been doing in there (i.e. defecating), or because cubicles are perceived to be more dirty? This is where the “out of order” signs on the urinals came into play. The researchers wanted to see what percentage of men would wash their hands after using a cubicle to urinate. Unfortunately the results were inconclusive – the hand-wash rate of 75 per cent after using cubicle for urinating did not differ significantly from the rates after using a cubicle for defecating, or from the rates after using a urinal.

However, another useful comparison was how long men washed their hands for after using a cubicle for defecating; after urinating in a cubicle; or after urinating in a urinal. This revealed that men’s duration of hand washing was more closely related to what they’d been doing, than to where they’d been doing it. This suggests public health notices need to use signage and other means to encourage men to wash their hands thoroughly regardless of what they’ve been doing.

In fact, based on this study, members of both genders need more encouragement to wash their hands more diligently. Looking at the median hand washing durations (17.5 seconds for men using cubicles for defecating; less than 10 seconds for women, and for men using urinals), both genders were well short of the Centers for Disease Control and Prevention recommendation that we should wash our hands for a minimum of 20 seconds to have any meaningful chance of removing harmful germs.

You might be wondering if it’s ethical for psychologists to lurk about in public loos observing people’s lavatorial habits. Berry’s team argue that it is, given the seriousness of the health issues involved, and so long as patron anonymity is protected, and that their “public-private life was not threatened or intruded upon”.


Thomas D. Berry, Daniel R. Mitteer, and Angela K. Fournier (2014). Examining Hand-Washing Rates and Durations in Public Restrooms: A Study of Gender Differences Via Personal, Environmental, and Behavioral Determinants. DOI: 10.1177/0013916514527590

Further reading
For The Psychologist magazine, Nick Haslam argues that psychologists should stop averting their eyes from the bathroom.

Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.

Working memory training does not live up to the hype

According to CogMed, one of the larger providers of computerised working memory training, the benefits of such training is “comprehensive” and includes “being able to stay focused, resist distractions, plan activities, complete tasks, and follow and contribute to complex discussions.” Similar claims are made by other providers such as Jungle Memory and Cognifit, which is endorsed by neuroscientist Susan Greenfield.

Working memory describes our ability to hold relevant information in mind for use in mental tasks, while ignoring irrelevant information. If it were possible to improve our working memory capacity and discipline through training, it makes sense that this would have widespread benefits. But that’s a big if.

A new meta-analysis by Monica Melby-Lervåg and Charles Hulme has just been published in the February issue of the respected APA journal Developmental Psychology, which combined the results from 23 studies of working memory training completed up to 2011 (PDF is freely available). To be included, studies had to compare outcomes for a working memory training treatment group against outcomes in a control group. Most of the studies available are on healthy adults or children, with just a few involving children with developmental conditions such as ADHD.

The results were absolutely clear. Working memory training leads to short-term gains on working memory performance on tests that are the same as, or similar to, those used in the training. “However,” Melby-Lervåg and Hulme write, “there is no evidence that working memory training produces generalisable gains to the other skills that have been investigated (verbal ability, word decoding, arithmetic), even when assessments take place immediately after training.”

There was a modest, short-term benefit of the training on non-verbal intelligence but this disappeared when only considering the studies with a robust design (i.e. those that randomised participants across conditions and which enrolled control participants in some kind of activity). Similarly, there was a modest benefit of the training on a test of attentional control, but this disappeared at follow-up.

All of this suggests that working memory training isn’t increasing people’s working memory capacity in such a way that they benefit whenever they engage in any kind of task that leans on working memory. Rather, people who complete the training simply seem to have improved at the specific kinds of exercises used in the training, or possibly even just at computer tasks – effects which, anyway, wear off over time.

Overall, Melby-Lervåg and Hulme note that the studies that have looked at the benefits of working memory training have been poor in design. In particular, they tend not to bother enrolling the control group in any kind of intervention, which means any observed benefits of the working memory training could be related simply to the fun and expectations of being in a training programme, never mind the specifics of what that entails. Related to that, some dubious studies reported far-reaching benefits of the working memory training, without finding any improvements in working memory, thus supporting the notion that these benefits had to do with participant expectations and motivation.

A problem with all meta-analyses, this one included, is that they tend to rely on published studies, which means any unpublished results stuck in a filing cabinet get neglected. But of course, it’s usually negative results that get left in the drawer, so if anything, the current meta-analysis presents an overly rosy view of the benefits of working memory training.

Melby-Lervåg and Hulme’s ultimate conclusion was stark: “there is no evidence that these programmes are suitable as methods of treatment for children with developmental cognitive disorders or as ways of effecting general improvements in adults’ or children’s cognitive skills or scholastic achievements.”


Melby-Lervåg M, and Hulme C (2013). Is working memory training effective? A meta-analytic review. Developmental psychology, 49 (2), 270-91 PMID: 22612437 Free, full PDF of the study.

This meta-analysis only took in reviews published up to 2011. If you know of any quality studies into the effects of working memory training published since that time, please do share the relevant links via comments. 

–Further reading–
Brain training games don’t work.

Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.