Women's under-representation in fields such as engineering may result in part from female students' negative beliefs regarding these fields and their low self-efficacy for these fields. Empirical evidence indicates that computer-generated interface agents are effective in influencing students' interest, motivation, attitudes, and self-efficacy. Hence, in this experimental study, we investigated the potential of interface agents to serve as effective social models for changing attitudes regarding the utility of math and the hard sciences and self-efficacy for these fields. 113 middle-school students interacted with either a female or a male computer-generated interface agent or they did not interact with an interface agent. The findings from this study indicate that interface agents may be used effectively as social models for influencing middle school students' attitudes and beliefs about mathematics and the hard sciences and their mathematical ability. Nevertheless, the efficacy of the agent depended on the characteristics of the agent with the female agent tending to be the most effective regardless of the subject gender.