“…As van Geert explained, an example of this notion is Siegler's () overlapping waves approach. Consistently with Siegler's approach, moral motivational strategies can be differentiated in a developmental hierarchy, while being used in multiplicity simultaneously (Kaplan et al, ; Kaplan & Tivnan, , , ). That is, strategies can be complementary, but they vary qualitatively along a dimension of developmental distance (van Geert, , p. 661).…”