Why do people talk so much? Diamond gives several reasons: 1) They can't write things down and go back to the records, so talking and repeating verbally can help them remember stuff. 2) They have no modern diversions like books, movies, TV, the Internet. 3) Incessant gossip is critical for their safety.
The last part is critical because information can mean life and death --- Someone spotted fruits for foraging some distance southwest of the camp; someone spotted lion tracks nearby; someone got killed by a fallen tree in the woods yesterday; someone has fallen ill with suspected witchcraft; etc. Now it's become apparent that we moderns are no different. The exchange of information is critical too for our survival. The difference is that we don't have to get most of the useful information from talking to others all the time and try to remember by constantly repeating it. We can learn from books, newspapers, TV, YouTube, and the all-mighty Google. We can write things down and look them up later.
This is an astounding realization, for I just never realized how much humans survive on sharing information.
I have been wondering for quite a while lately about why we seem to have the tendency to be "addicted" to the Internet and uncontrollably reach for our Smart Phones every idle moment, despite the sense of stress and anxiety and being overwhelmed. No doubt, we are naturally predisposed to collect and share information, and the predisposition --- be it genetic, epigenetic, or some yet unknown mechanism that is vaguely known as "instinct" --- is too simple to distinguish useful information (eg, how to make fire and track animals) and useless information (eg, what shit came out of Donald Trump's mouth today). We are the species that gossip.
This realization brings up the question of the Jungian concept of "collective unconscious." I used to dismiss it and things like "ancient memory" that passes down generations as pseudoscience, but now I'm not sure. These instincts --- whatever the biological mechanism --- are real, such as the instinct to gossip, the fear of snakes or spiders, and the irresistible charm of fireplace. Where did they come from and how did they transmit over time? I don't know, and I find a genetic basis to be very unlikely.