Wolves, Dogs and Neoteny
Dogs are much more playful than wolves, and this can probably be understood as retention of juvenile behavior (called “neoteny”). Retaining existing juvenile behavior is accomplished far more easily than evolving a behavior from scratch. Many of the ways in which dogs interact with humans can be understood as a new application of behavioral adaptations designed for a pack — the owner takes on the role of the leader of the pack.
from "The 10,000 Year Explosion: How Civilization Accelerated Human Evolution"
Quoted on Sat Aug 29th, 2009