“…Several of the behaviors in our categories of social behavior ( Figure 1) have already been shown to exhibit repeatable individual differences where some individuals exhibit more of the given social behavior than others regardless of circumstances or context. Proactivity has been shown to be repeatable over time (reviewed by Réale et al, 2007) and there are consistent individual differences in parental behavior (Budaev, Zworykin, & Mochek, 1999;Fairbanks, 1996;Maestripieri, 1993;Schwagmeyer & Mock, 2003), affiliative behavior (Seyfarth, Silk, & Cheney, 2012;Webb, Franks, Romero, Higgins, & de Waal, 2014), and alloparental behavior in cooperative breeders (Carter, English, & Clutton-Brock, 2014;English, Nakagawa, & Clutton-Brock, 2010). Furthermore, individual differences in measures of HPA-axis activity exist (Baugh, van Oers, Dingemanse, & Hau, 2014;Ellis, Jackson, & Boyce, 2006;Fletcher, Dantzer, & Boonstra, 2015) and has been observed to co-vary with different behavioral types (Carere et al, 2010;Cockrem, 2007;Koolhaas et al, 1999;Korte, Koolhaas, Wingfield, & McEwen, 2005).…”