Although Piaget's research has been incredibly influential in the field of cognitive development, it has fallen out of favor in the past twenty to thirty years, in part because of advances in technique that have illustrated a different set of abilities in children than that observed by Piaget and in part because of several principled criticisms of his theory. Some of the features of the theory that have been criticized are 1) the lack of evidence for qualitatively different stages, 2) Piaget's focus on the physical environment to the exclusion of the social environment, and 3) the theory's vagueness about the mechanisms of developmental change. Two approaches that attempt to integrate new evidence and provide models that are not vulnerable to those criticisms--the information-processing approach and Vygotsky's social learning approach-- are described below.

Whereas Piaget's account of development postulates distinct stages, information-processing accounts almost uniformly postulate incremental advances in cognitive abilities over the course of development. Working memory, for instance, has been shown to increase gradually over the course of childhood: over the short term, a four-year-old can remember about four letters, an eleven-year-old can remember about six, and an adult can remember seven or eight. These increases in basic cognitive resources may be the driving force behind many of the advances that Piaget though were due to the dual processes of assimilation and accommodation. With increased working memory, the child's ability to hold images, words, and operations in mind increases. This increase may, in combination with various skills and acquired knowledge, be enough to account for development.

Although the information-processing account avoids the pitfalls of an overly stage-based theory, it does not rectify Piaget's failure to account for the effect of the child's social environment on cognitive development. Lev Vygotsky, a Russian psychologist who wrote on development in the 1920s and 1930s, offered a sociocultural perspective on development that continues to influence research today. Vygotsky argued that the most important environment for a child was not, as Piaget had suggested, the child's physical surroundings, but rather the social context within which the child developed. Within every human society, older siblings, peers, or parents act as models for the child. The child jointly participates in a variety of activities, at first playing only an observational role but taking on greater and greater responsibility as the child's experience grows. Vygotsky's theory explicitly takes into account the effect of culture and society on development.