During interpersonal interactions, humans naturally mimic one another's behavior. Mimicry can be a measure of rapport or connectedness. Researchers have found that people will mimic robots, virtual avatars, and computers in social situations similar to those in which they mimic people. In this work, we explored how people's perceptions of a robot during a social interaction influenced their expressivity and social behavior. Specifically, we examined whether the presentation or framing of a robot as a social agent versus as a machine could influence people's behavior and responses, independent of any changes in the robot itself. Participants engaged in a ten-minute interaction with a social robot. For half the participants, the experimenter introduced the robot in a social way; for the other half, the robot was introduced as a machine. Our results showed that framing did have an effect: people who perceived the robot more socially spoke significantly more and were more vocally expressive than participants who perceived the robot as a machine. This study provides insight into how the context of a human-robot interaction can influence people's reactions independent of the robot itself.