Deficits in sociability in adult male BTBR T+tf/J (BTBR) and repetitive self-grooming in BTBR and LP/J as compared to C57BL/6J (B6). Sociability in the automated three-chambered apparatus is defined as spending significantly more time in the side chamber containing a novel mouse than in the side chamber containing a non-social novel object. (A) Repeated Measure ANOVA revealed significant sociability in B6 (F1,9 =63.01, p<.0001) and LP/J (F1,17 =18.83, p<.001), but not in BTBR(F1,11=3.26, NS); (B) Time spent sniffing the novel mouse versus the novel object provides a complementary measure of sociability. Repeated Measure ANOVA revealed that B6 (F1,9 =86.63 p<.0001) and LP/J (F1,17=28.44 p<.0001) spent more time sniffing the novel mouse than the novel object, while BTBR (F1,11=3.26, NS) did not; (C) Total entries into the side chambers showed a significant main group effect (One Way ANOVA, F2,37 =4.85, p<.01). Scheffe tests revealed that BTBR made more entries than LP/J (p<.05); (D) Repetitive self-grooming was simultaneously measured during the social approach test. One Way ANOVA indicated that LP/J and BTBR spent more time engaged in self-grooming as compared to B6 (p<.0001 for each comparison). B6 N=10, LP/J N=18, BTBR N=12. Panels A and B, *p<.01 comparison between novel mouse and novel object sides; Panel C: #, p<.05 BTBR versus LP/J; Panel D, * p<.0001 versus B6.