The 1st study examined the hypothesis that feeling lonely is related to a self-perceived lack of self-disclosure to significant others. 37 male and 38 female undergraduates rated themselves on the UCLA Loneliness Scale and the Jourard Self-Disclosure Questionnaire. Analyses showed that for males and females, loneliness was significantly and linearly related to a self-perceived lack of intimate disclosure to opposite-sex friends. For females, loneliness was also associated with a perceived lack of self-disclosure to same-sex friends. The 2nd study investigated the relationship between loneliness and actual disclosure behavior. 24 lonely and 23 nonlonely Ss were paired with nonlonely partners in a structured acquaintanceship exercise. Both opposite-sex and same-sex pairs were included in the design. Postexercise ratings by partners indicated that lonely Ss were less effective than nonlonely Ss in making themselves known. Analysis of the intimacy level in the conversations showed that lonely Ss had significantly different patterns of disclosure than nonlonely Ss. The authors suggest that the self-disclosure style of the lonely person impairs the normal development of social relationships. (37 ref) (PsycINFO Database Record (c) 2006 APA, all rights reserved).