(p. D1) A study published in February  in the British Journal of Psychology looked at 15,000 respondents and found that people who had more social interactions with close friends reported being happier–unless they were highly intelligent. People with higher I.Q.s were less content when they spent more time with friends. Psychologists theorize that these folks keep themselves intellectually stimulated without a lot of social interaction, and often have a long-term goal they are pursuing.
For the full story, see:
ELIZABETH BERNSTEIN. “Why Making New Friends Is Harder for Grown-Ups.” The Wall Street Journal (Tues., April 19, 2016): D1 & D4.
(Note: the bracketed year was added.)
(Note: the online version of the story has the date April 18, 2016, and has the title “The Science of Making Friends.”)
The academic psychology paper mentioned above (with title ellipsis in original), is:
Li, Norman, and Satoshi Kanazawa. “Country Roads, Take Me Home… to My Friends: How Intelligence, Population Density, and Friendship Affect Modern Happiness.” British Journal of Psychology (epublished on Feb. 1, 2016) DOI: 10.1111/bjop.12181.