16 Scientific Studies Linked to Happiness

What, according to science, makes people happy? We’ve summarised a collection of popular and/or interesting studies below. Apart from where any finding has been repeatedly replicated by other scientists, happiness research in general should be treated with generous scepticism. This point should go without saying when dealing with any new study that is reported in the general media, however the frequency with which scientific papers are misunderstood and misrepresented suggests that more vigilance is required on the part of audiences and educators alike. If you haven’t seen it already, John Oliver has a hilarious segment on how scientific research has a history of being distorted by pop journalism, particularly morning talk shows.

Happiness research is one of the most notoriously slippery areas of science. For any surprising finding, it’s often possible to find contradictory evidence from another source. Sometimes this has to do with different starting definitions of happiness. A more significant issue has to do with the methods of analysis and experimental design. Factors like sample size, sample composition, study length, location, number of researchers, the journal of publication, and who funded the study can all have important implications. For example, according to one study North Korea is the 2nd happiest country on the planet, while the US ranks 203rd. Incidentally, the study was conducted by North Korea. Failure to properly communicate the construction elements that underpin a particular study’s conclusions carries a certain degree of risk. However, failure to put scientific discoveries in terms the layperson can understand and enjoy is to obstruct the cause of science, and to risk irrelevance.

The following list can be viewed as a launching pad for further investigation. (Links to articles or original papers are provided.) We acknowledge that presenting information in this way may risk oversimplifying complex studies, and may serve as a basis to justify previously held opinions. In all things journalism, proceed with caution.

01. High Quality Relationships are the Best Predictor of Health & Happiness. The Grant Study is a famous 75-year-long study tracking the physical and mental health of over 200 Harvard students that began in 1938. The current director of the study, Robert Waldinger, reveals some of the secrets to happiness in his 2015 TED Talk. The most important finding is that good quality relationships keep us healthy and happy. Source.

02. Money Can Buy Happiness (Up to a Point). A 2010 Princeton University study that was widely reported in the media found US$75,000 is the magic number for happiness (in terms of overall life satisfaction but not day-to-day contentment). Lower than this point decreases satisfaction, and higher than this point doesn’t increase satisfaction. The researchers used data from Gallup surveys of 450,000 Americans. Source. 

03. Money Can Buy Happiness (If You Align Spending With Your Personality). A Cambridge University study involving 625 people examined the link between purchase happiness and personality traits using the Big Five model (extraversion, openness, agreeableness, conscientiousness, neuroticism). The results reported were that purchases aligned with personality traits tended to lead to increased happiness. For example, someone high in agreeableness who spent his or her money on charity was more likely to be happy with the decision than someone with a different dominant personality trait. Source. 

04. Spending Money on Experiences Rather Than Things Makes People Happier. A 2009 study of 154 people living in San Francisco looked at their retrospective satisfaction with purchases made in the last 3 months — either material (e.g., a watch) or experiential (e.g., travel). Most reported general satisfaction with their purchases, however those who spent their money on experiences tended to show higher satisfaction. Source. 

05. Lottery Winners Aren’t Any Happier Than Paraplegics (After a Year). This famous 1978 study contrasted a group of 22 major lottery winners with 29 recent paraplegics, and the two groups measured roughly the same level of happiness a year after the occurrence of these two respectively life-changing events. This study is often connected to the concept known as “Hedonic Adaptation”—humans eventually return to a stable level of happiness after major positive or negative events. Source.

06. Autonomy is More Important than Money for Happiness. Results of a major meta-analysis involving 420,599 people from 63 countries spanning nearly 40 years published by the American Psychological Association reported “freedom and personal autonomy are more important to people’s well-being than money.” Interestingly, the authors observed “a very consistent and robust finding that societal values of individualism were the best predictors of well-being.” However, the study authors also note that extreme levels of autonomy may not be beneficial. Source. 

07. People Are Happiest Between the Ages of 65 and 79. A 2016 UK government report analysed well-being data for around 300,000 adults, finding that “those aged 65 to 79 tended to report the highest average levels of personal well-being.” The lowest levels of happiness were reported between the ages of 45 to 59. Source. 

08. “Happiness Shocks” Make You More Productive. A 2015 British study involving 700 people found a link between “happiness shocks” and productivity. Researchers showed participants either a 10-minute comedy clip or gave them drinks and snacks. Happiness was then rated to ensure it had increased. Next, the participants were given a series of tasks and assessed their levels of productivity. Those who received the happiness shocks were, on average, 12% more productive (20% at the top end), as compared with the control group. Source. 

09. Volunteering Can Make You Happier. As reported in the Huffington Post in 2013, researchers at the University of Exeter Medical School, UK, “reviewed 40 studies from the past 20 years on the link between volunteering and health.” The research revealed that volunteering is correlated with increased well-being, decreased depression, and a 22% reduction in the risk of dying. Source. 

10. A Daily Gratitude Journal Can Make You Happier. A 2005 study followed participants who wrote down 3 things they were grateful for at the end of each day for 1 week, finding that participants tended to feel happier and less depressed. The daily gratitude practice is considered to be one of the most practical and effective activities for increasing happiness, which is described in more detail on Berkeley’s Greater Good website. Source

11. Sugary & Processed Foods May Increase Risk of Depression. Research published in The British Journal of Psychiatry involving 3486 people looked at the link between diet and depression. One group was given a "whole food" diet loaded with vegetables, fruits, and fish, while the other was given a "processed foods" diet loaded with sweetened desserts, fried foods, processed meats, refined grains, and high-fat dairy. After 5 years, the whole food group had a 26% reduced risk of depression, while the processed foods group had a 58% increased risk. Source. 

12. Probiotics May Protect Against Anxiety & Depression. A gastroenterology researcher and his colleagues at a Canadian University drew attention when they found anxiety and depressive behaviour could be induced in calm mice simply by transplanting gut microbes from anxious mice. They reported that two probiotic strains—lactobacillus and bifidobacterium—reduce anxiety-like behaviour in mice. The research on probiotics in connection with human health is extremely limited at the present time, however in 2015 TIME magazine reported on the first ever study involving a randomised controlled trial of 40 people given a probiotic versus a placebo for four weeks and found that “people who took the probiotic reported significantly less reactivity to sad mood than the control group.” Source. 

13. Two to Eight Daily Portions of Fruit and Veg Could Significantly Increase Happiness. A study reported by Reuters examined the link between fruit and vegetable intake and well-being in 12,000 adults over several years. Those who switched from zero portions of fruit and veg per day to eight saw their scores in life satisfaction increase significantly or “about equivalent to going from unemployment to a job.” This effect is produced within about two years, however the researchers say that adding even two portions a day would still result in “a large gain in happiness.” The reason: One of the study authors told VICE magazine that, in his opinion, it is most linked to the “folate, carotene, and the micro-organisms that make up our gastrointestinal tract" which can have a major impact on mood. Source. 

14. Quitting Facebook May Make You Happier. Copenhagen’s Happiness Research Institute found that a "treatment group" who couldn’t use Facebook for one week reported significantly higher levels of life satisfaction than those who used it everyday. There were 1,095 participants in the study. Source. 

15. Excessive Cell Phone Use May Decrease Happiness. A 2014 study conducted by Kent University followed the cell phone habits of 500 American college students. The researchers found that “high frequency cell phone users tended to have lower GPAs, higher anxiety, and lower satisfaction with life (happiness) relative to their peers who used their cell phones less often.” The study, which was the first major investigation of its kind, was published in the journal Computers in Human Behaviour. Source. 

16. Less than 30 Minutes of Social Media Time May Be Optimal for Happiness. The 2015 Australian Wellbeing Index looked at a variety of happiness indicators for around 60,000 participants. One of the findings reported was those who used social media for no more than 30 minutes a day were the only group to report happiness above the normal range. Source.