Previous investigations in Fmr1 male KOs often show decreased sociability in both social partition and the three‐chambered social task (Liu & Smith, 2009; Moy et al., 2009; Pietropaolo, Guilleminot, Martin, D'Amato, & Crusio, 2011), which is consistent with ASD and FXS symptomologies. This evidence concerns the gene FMR1 and fragile X syndrome.