Group survival, argues anthropologist Robin Dunbar, necessitates strong social ties and frequent sharing of information among individuals. “In a nutshell,” he wrote in 1996, “I am suggesting that language evolved to allow us to gossip.”

• Millions of years ago, African apes begin to de­vote time that could have been spent for­aging to mu­tual groom­ing. The prac­tice strength­ens al­li­ances and hi­er­ar­chies, al­low­ing pop­u­la­tions to band to­gether to ward off pred­a­tors more successfully.
• Though Homo erectus, which appears around two mil­llion years ago, lacks a fully de­vel­oped hu­man vo­cal ap­pa­ra­tus, “vo­cal groom­ing” in the form of mean­ing­less chat­ter sup­ple­ments phys­i­cal groom­ing, re­sult­ing in lar­ger communities.
• Homo ne­an­der­thal­ensis, which co­ex­ists with an­a­tom­i­cally mo­dern hu­mans in Eur­asia for mil­lennia, seems ne­ver to have de­vel­oped lan­guage—an evo­lu­tionary dis­ad­van­tage for a spe­cies com­pet­ing for re­sources with the lin­guis­tically de­vel­oped Homo sapiens.
• Sometime after the emer­gence of Homo sa­piens around 250,000 years ago, the spe­cies de­vel­ops speech, which en­ables in­di­vid­uals to quickly ex­change re­ports about others, in­clud­ing who might be free­load­ing. This more ef­fi­cient means of ma­nag­ing a group per­mits larger, more com­plex populations.
• Extending Dunbar’s theory into the di­gital age, so­ci­ol­o­gist Zey­nep Tu­fekci has found that ac­tive so­cial me­dia users are sig­nif­i­cantly more likely than their peers to ex­press cu­ri­osity about other peo­ple’s lives and keep in touch with friends. Whether this con­fers evo­lu­tion­ary ad­van­tages re­mains to be seen.