“…Infants as young as 5 months (Hamlin et al, 2007, 2010, 2011; Hamlin and Wynn, 2011, 2012) and older infants and toddlers (Geraci and Surian, 2011; Buon et al, 2014; Scola et al, 2015; Woo et al, 2017; Chae and Song, 2018) seem capable of socially evaluating the behavior of others and appear to show a preference for prosocial others (for reviews, see Martin and Olson, 2015; Holvoet et al, 2016; Van de Vondervoort and Hamlin, 2018) as well as those who are similar to themselves along some dimension (e.g., Hamlin and Wynn, 2012; Mahajan and Wynn, 2012; Hamlin et al, 2013; Burns and Sommerville, 2014; Gerson et al, 2017). These findings have led researchers to hypothesize that we may be born with something akin to an innate moral core (Cook, 2013; Hamlin, 2013) or early strong tendencies (Martin and Olson, 2015; Holvoet et al, 2016; Hare, 2017), which include a preference for similar others (Hamlin and Wynn, 2012; Mahajan and Wynn, 2012; Hamlin et al, 2013) and that these tendencies observed during infancy may predict social and behavioral adjustment at 4 years of age (Tan et al, 2018).…”