Six-month-old liliana has been exclusively breast-fed since birth and thus has never had milk from a bottle. the first time liliana is offered a bottle, she tries to suck on it the way she is used to sucking. however, her sucking behavior is not successful with the bottle. she thus has to adapt her sucking in order to get sufficient milk from the bottle. liliana's new understanding of how to suck on the bottle is an indication that she has engaged in the process of