Fig. 3.

Approach behaviour in the group-housed-only and socially isolated-only housing conditions. a, b Number of approaches for group-housed (GH) and socially isolated (SI) mice in the novel environment (Day 1) (a) and the familiar environment (Days 2–4) (b). Data are shown as mean ± SE for each approach direction (group-housed mouse to group-housed mouse (GHtoGH) or socially isolated mouse to socially isolated mouse (SItoSI)). Each mouse could approach three other mice, for 36 possible approaches by the 12 mice in each condition (n = 36 for each approach direction). Thus, the means are the sum of all approaches for a given direction divided by 36. p = 0.22 in the novel environment (two-way repeated measures ANOVA) and *p < 0.05 in the familiar environment (three-way repeated measures ANOVA followed by simple effects analysis). c, d Duration of social interaction per approach for group-housed and socially isolated mice in the novel (c) and familiar (d) environments. Data are shown as mean ± SE (the average duration of each social interaction, n = 36 possible interaction pairs). Analysed by two-way repeated measures ANOVA in the novel environment and by three-way repeated measures ANOVA followed by simple effects analysis in the familiar environment