(A) The B6 control strain displayed normal sociability after saline vehicle treatment. In Cohort 4, B6 treated with AMPH spent more time in the novel mouse chamber compared to the time spent in the novel object chamber. (B) BTBR exhibited its characteristic lack of sociability after both saline and AMPH. (C) B6 displayed sociability on the more sensitive parameter, time spent sniffing the novel mouse as compared to time spent sniffing the novel object, after both saline and AMPH. (D) BTBR exhibited its characteristic lack of sociability on the sniff parameter following saline vehicle administration. BTBR treated with AMPH exhibited significant sociability on the sensitive sniff time parameter. *p < 0.05, novel mouse versus novel object. (E) B6 and (F) BTBR displayed more entries into the side chambers after AMPH, indicating a general increase in exploratory activity during the social approach task. *p < 0.05 AMPH 2.0 mg/kg i.p. versus SAL. N = 8–10 per dose for each strain in Cohort 4.