Dogs are Evolved from Wolves Through Artificial Selection

Take the domestic dog (Canis lupus familiaris), a single species that comes in all shapes, sizes, colors, and temperaments. Every single one, purebred or mutt, descends from a single ancestral species—most likely the Eurasian gray wolf—that humans began to select about 10,000 years ago. The American Kennel Club recognizes 150 different breeds, and you’ve seen many of them: the tiny, nervous Chihuahua, perhaps bred as a food animal by the Toltec of Mexico; the robust Saint Bernard, thick...

 Challenging Inhibited Behavior in Children

But with the right balance, parents can modify even the most difficult side of their children's temperaments. As an example, consider those 15 percent or so of toddlers who are very inhibited—kids like Andrew, whose right frontal lobe explodes with anxiety whenever he's confronted by new people or a new environment. While many of these children don't change, about 40 percent do lose their extreme timidity by kindergarten. Researchers have observed that these are the youngsters whose parents...