A child has learnt to deal with a younger sibling by using physical intimidation. If the child uses the same tactics on a peer, this indicates

Applying an already-learned tactic to a new person fits the new experience into an existing schema, which Piaget called assimilation.

Social learning is Bandura's idea of acquiring behaviour by observing and imitating others, but here the child reuses a self-formed strategy.

Equilibrium is the balance between assimilation and accommodation, not the act of reusing a schema.

Accommodation is modifying an existing schema when it fails, the opposite of applying it unchanged.

Assimilation interprets the world through what one already knows.

Piaget paired assimilation and accommodation as the twin processes of adaptation in cognitive development.