Last week my editor at the New York Times asked me to write an article about the evolution of crying, to accompany an article by Sandra Blakeslee on colic. Both articles (mine and Blakeslee’s) are coming out tomorrow. As I’ve written here before, human babies are by no means the only young animals that cry, and there’s evidence that natural selection has shaped their signals, whether they have feathers or hair. Among animals, there’s a lot of evidence that infants can benefit from manipulating their signals to get more from their parents. On the other hand, evolution may sometimes favor "honest advertisements" that prevent offspring from deceiving their parents. Human crying may be the product of the same