Note that this bidirectional relational responding (mutual entailment) is being reinforced in a particular context. Certain features of the context remain the same, regardless of the animals being compared. For example, the father always points to an animal and says, “This is bigger.” And then he always asks, “Which is smaller?” and “Which is bigger?” These are contextual cues that let the boy know that making a particular type of relational response will be reinforced.