According to Jean Piaget, this is the second substage of sensorimotor thought. This substage is apparent in children between about 1 month to 4 months of age. Two primary schemes are apparent. First, the infant repeats an action that was once associated with a reflex, but is now completely separated from its eliciting stimulus (e.g., sucking when no bottle or nipples are present). Second, after accidentally causing an interesting event with one's own body (e.g., kicking feet), the infant repeats the action many times.