A study investigated the relationship between levels of communication apprehension (high or low) and eight heterosocial (between sexes) communicative behavior variables--conditioned anxiety, heterosocial skills, heterosocial apprehension, activity, proximity, heterosocial expectations, physical attractiveness, and heterosocial importance. In addition, the study evaluated the validity of the Relational Practices Instrument (RPI), which had been developed to measure the eight variables. Subjects were 200 undergraduate college students who completed the RPI and the Personal Report of Communication Apprehension, which was used to classify students as high or low apprehensive. The results showed that low apprehensive students reported greater degrees of heterosocial skills and perceived self-physical attractiveness, and lower degrees of conditioned anxiety and heterosocial apprehension than did high apprehensive students. The findings revealed no significant differences between the two groups on heterosocial expectations, importance, activity, or proximity. The findings provide some support for construct validity of the RPI. (FL)