Object Permanence: The concept that an object exists even when you can't see it. He doesn't have object permanence because he can't find his mom.
"I'm just taking a shower! I'm still here!"
"Where'd you go?"
Critical Periods: Windows when your brain is more susceptible to learning or damage. She developed perfect pitch because she has been playing music since she was young, (during her Critical Period).
"That's an F Sharp!"
Maturation: The action or process of learning; predetermined behavioral patterns. She is taking her first steps on her first birthday. She has matured enough to walk because she's devolved the essential skills to.