“…In the course of early development, the tendency to act altruistically shows a marked increase (Knafo & Plomin, ; Svetlova et al., ). Given the widespread interest, different theoretical approaches have attempted to account for these phenomena (for discussions, see Carpendale, Hammond, & Atwood, ; Cortes Barragan & Dweck, ; Dahl, Campos, & Witherington, ; Dunfield, ; Hammond, ; Hay, ; Martin & Olson, ; Paulus, ).…”