From the French for ‘time lag’, the Piagetian idea that cognitive abilities develop at different rates in the same individual. For example, children solve conservation of number tasks before they solve conservation of mass tasks and the latter before they can conserve weight, a phenomenon termed horizontal décalage (i.e., the inability of a child to transfer one conservation ability to another type). There is also vertical décalage: the partial operation of a cognitive structure at an earlier stage before it is fully developed. At the level of society, one may also talk about an historical décalage: a society (e.g., via the media) may contend that its new generations are either behind or ahead of what was expected of others previously (cf. Flynn effect).
See Cognitive structures, Conservation, Flynn effect, Scheme, Stage, Structure d’ensemble