δ-catenin KO induces social dysfunction in mice. Total interaction time and the discrimination index of (A) sociability and (B) social novelty in female and male WT and KO mice in the three-chamber test (n = number of animals, WT female = 16, KO female = 14, WT male = 20, and KO male = 15, *P < 0.05, **P < 0.01, ***P < 0.001, and ****P < 0.0001, For total interaction time, Two-way ANOVA with Tukey test was used. For the discrimination index, the unpaired two-tailed Student’s t test was used. n.s. indicates no significant difference). Mean ± SD. Total interaction time and the discrimination index of (A) sociability and (B) social novelty in female and male WT and KO mice in the three-chamber test (n = number of animals, WT female = 16, KO female = 14, WT male = 20, and KO male = 15, *P < 0.05, **P < 0.01, ***P < 0.001, and ****P < 0.0001, For total interaction time, Two-way ANOVA with Tukey test was used. For the discrimination index, the unpaired two-tailed Student’s t test was used. n.s. indicates no significant difference). Mean ± SD.