(D) 3-chamber test (WT n=11 mice, crmp2-/- n=13 mice). In sociability phase, WT mice spent significantly more time with a social partner (stranger 1), unlike knockouts. (WT - stranger 1: 0.14±0.01, object: 0.07±0.007 (p=0.0001); crmp2-/- - stranger 1: 0.07±0.01, object: 0.04±0.006 (p=0.07)). In social novelty phase, when an object was substituted with a second social partner (stranger 2), both WTs and knockouts preferred novel mice to known mice. (WT - stranger 1: 0.03±0.006, stranger 2: 0.09±0.008 (p<0.0001); crmp2-/- - stranger 1: 0.02±0.004, stranger 2: 0.05±0.01 (p=0.02)). Mean ± SEM, *p<0.05, ***p<0.001, t-test. 