Eagly has worked on various topics in psychology including prejudice, sex differences, leadership styles, attitudes, and feminism. She discusses not only gender differences and stereotypes but also the underlying idea of prejudice, which can apply to not only gender but also other disadvantaged groups. Eagly uses much of her research to show that discrimination happens when the individual steps outside of the given stereotype ascribed to their group. This is a basis for much of her research on gender discrimination and stereotypes. One of her most important contributions to the field of psychology is her theory on role congruity, the belief that prejudice arises when one social groups' stereotype mismatches their valued success in other social roles. That is, society views one social groups role to be exclusive to that group in particular, and that venturing outside this could not be a successful endeavor, thus creating prejudicial attitudes. Eagly explores this idea in her research to show that the attributes ascribed to the group are not necessarily negative, but just different from that which is assumed of the group. This theory has been most noteworthy in her research regarding sex differences and leadership among women in the workplace and in the home. Much of her research focuses on feminist ideas and upward mobility in both the workforce and in traditional gender roles for women. Her contributions in these areas of psychology have illuminated issues concerning gender stereotypes in modern American society. Madeline Heilman and Eagly research what they call a "lack of fit" in workplace employment, which is based on the same idea as the role incongruity. This idea emphasizes how there is the assumption that the stereotypical attributes of the group are not ideal or fit for the task or job position in question. Eagly has contributed several notable studies to the body of research on sex differences. For example, her work in the area of mate-preferences showed that men and women who held more traditional gender ideologies preferred more gender stereotypical qualities in a partner. Women with more traditional attitudes looked for older mates while more traditional men sought younger mates compared to males and females who reported less traditional gender ideologies. In an additional study, Eagly found that participant's mate-preferences could be shifted by asking them to see themselves in different marital roles. When instructed to envision oneself in the provider role, participants placed a greater emphasis on a mate's homemaker skills and the preferred age for the mate decreased. She also found, however, that changing one's expected marital role could not completely eliminate gender differences in preference for earning potential; women consistently looked for a greater earning potential in a mate compared to men. Other research that Eagly participated in looks at women who were highly educated and their anticipated marital roles. This study shows that these women anticipated inequality in areas such as employment hours, salary, housework and childcare in comparison to the amount of work that they expected their husbands to do. Further research in this study also shows that women who anticipated greater employment opportunity showed a general decrease in gender role assumptions, but also felt that they felt their relationships with their family and emotional well-being would be affected adversely. Eagly developed the social role theory which attributes current sex differences to the labor division between men and women. This theory emphasizes the social component of sex differences. It operates around the idea of correspondence inference, which is the tendency to ascribe a person's behavior to her or his disposition or personality and to underestimate the extent to which situational factors elicited the behavior. Eagly suggests that men and women were constrained to certain roles in the work force and then assumed to embody the psychological characteristics of those roles without exception.
