The ability to design tailored messages for specific listeners is an important aspect of human communication. The present study investigates whether a mere belief about an addressee's identity influences the generation and production of a communicative message in a novel, non-verbal communication task. Participants were made to believe they were playing a game with a child or an adult partner, while a confederate acted as both child and adult partners with matched performance and response times. The participants' belief influenced their behavior, spending longer when interacting with the presumed child addressee, but only during communicative portions of the game, i.e. using time as a tool to place emphasis on target information. This communicative adaptation attenuated with experience, and it was related to personality traits, namely Empathy and Need for Cognition measures. Overall, these findings indicate that novel nonverbal communicative interactions are selected according to a socio-centric perspective, and they are strongly influenced by participants' traits.