Reduced social behaviors in Shank3 heterozygous and wild-type littermate mice. (A) Adult male-female social interactions. Left: Total duration of social interactions, scored as cumulative seconds spent by the male subject in sniffing the nose, anogenital and other body regions of an unfamiliar adult estrus B6 female mouse during a 5-min test session in a clean, empty mouse cage. *P = 0.02. Right: Number of ultrasonic vocalizations emitted during the social interaction test session (*P = 0.003) (n = 12 for wild-type (WT) and n = 14 for heterozygous (Het) mice). (B) Olfactory habitutation and dishabituation to nonsocial and social odors, measured as cumulative time spent sniffing a sequence of identical and novel odors delivered on cotton swabs inserted into a clean cage (n = 8 mice/genotype).