Pinker’s Chapter 8 supplement — early aggression is common; development is largely inhibition
Pinker summarizes Richard Tremblay’s developmental research by reversing the usual question. Physical aggression does not first appear when an older child discovers violent media or bad peers: kicking, biting, hitting, and fighting are common in toddlerhood, with the average rate peaking around age two and then declining. The more revealing question is therefore how children learn not to use aggression—through language, self-control, empathy, predictable consequences, social norms, and safer ways to get needs met.
This is a population-level pattern reported in a 2011 synthesis, not a claim that every two-year-old is violent, that early aggression is harmless, or that later serious aggression is inevitable. Individual development, caregiving, neurodevelopment, trauma, peers, and context still matter. Chapter 8 synthesis · The hydraulic model and early aggression, PDF pp. 668–669 (file not included in this release) · Tremblay’s developmental reframing, PDF p. 669 (file not included in this release)
From the notebook