I recently proposed a socio-relational framework that suggests that phenotypic variation in the expression of discrete affect behaviors (e.g., expressed anger vs. sadness) may reflect two basic dimensions of behavioral response. The first dimension is the motivation to selectively attract or avoid interactions with different people. The second dimension is the behavioral display of either personal capacity or trustworthiness cues, often through the expression of dominant and submissive behaviors, respectively (Vigil, in press). Sex differences in affect behaviors (e.g., externalizing vs. internalizing displays) may reflect developmental sensitivities to advertise capacity and trustworthiness cues somewhat differently, due to the unique social dynamics and relational constraints under which males and females evolved. In this study, I use a series of self-report questionnaires to examine two basic assumptions of the framework. The first assumption is that sex differences in nonverbal affect behaviors (aggression vs. crying) reflect the desire for, and are effective for causing other people to either avoid or comfort the individual, respectively. I hypothesized that males would report a greater likelihood of responding to various distress moods with aggressive, rather than crying behaviors, and that males would desire, and believe male peers similarly desire distancing responses from others when feeling these moods. Instead, females were hypothesized to report more crying behaviors, and to desire, and believe female peers desire more comforting responses from others. The second assumption is that people are more accurate at inferring the desired social responses (i.e., to be left alone or comforted when experiencing distress) of same-sex, rather than oppositesex peers. I hypothesized that people's beliefs of same-sex peers are more similar to the self-reported desires of the male and female participants, themselves, than their beliefs of opposite-sex peers. The results are consistent with the first assumption, but show that only men were more accurate at inferring same-sex, rather than opposite-sex desires. In general, the findings are consistent with the socio-relational framework that suggests that humans may have evolved specialized expressive behaviors and interpersonal styles for communicating and interacting with same-sex affiliates.