In an effort to guide the development of a computer agent (CA)-based adviser system that presents patient-centered language to older adults (e.g., medication instructions in portal environments or smartphone apps), we evaluated 360 older and younger adults' responses to medication information delivered by a set of CAs. We assessed patient memory for medication information, their affective responses to the information, their perception of the CA's teaching effectiveness and expressiveness, and their perceived level of similarity with each CA. Each participant saw CAs varying in appearance and levels of realism (Photo-realistic vs Cartoon vs Emoji, as control condition). To investigate the impact of affective cues on patients, we varied CA message framing, with effects described either as gains of taking or losses of not taking the medication. Our results corroborate the idea that CAs can produce a significant effect on older adults' learning in part by engendering social responses.