If a toddler is hitting does that make them aggressive? How do you teach a child not to hit? And how long will it take? And why do some children never struggle with this behavior? 1. No. Though it doesn't change that it hurts the receiver. Hitting in toddlers is a sign of lack of impulse control and can be triggered by anger, exhaustion, an unmet need, or even excitement and happiness (slap 😊 happy!). The more understanding you have about the "why" the easier it will be to help them work toward