SciCheer book reviewer Joanne Manaster tells us what she thinks about the soft-on-science-but-heavy-on-social-etiquette book, I See Rude People. If I get this book as a gift, I’ll know why (hint: texting while talking to others. I know! I know!). One cool reminder Joanne pulls from the book deals with the brain’s limited capacity to communicate with large numbers of people. How many people do you interact with on a given day (factor in the folks at the supermarket, school, online friends, etc)? More than 150? If so, your brain’s probably being compromised. Back when we ran with traditional tribes, our brains nimbly handled communications among 150 *or fewer* other tribesmen (the average size of a tribe was 150). Fast-forward to today, and it turns out our brains haven’t evolved all that much in this regard: the ability to communicate well begins to break down after our circle extends past 150 people.