Stages of Development

Transfers

Piaget described cognitive development as proceeding through four major stages: sensorimotor (birth to ~2 years), preoperational (~2 to ~7), concrete operational (~7 to ~11), and formal operational (~11 onward). The “stage” metaphor is so naturalized in developmental psychology that its metaphorical structure is often invisible, but it imports a specific set of assumptions from the source domain of journeys and theatrical performance.

• Invariant sequence — a journey proceeds through waypoints in order. You do not skip from the first town to the fourth. Piaget’s stages work the same way: every child passes through the same sequence, regardless of culture, education, or intelligence. The speed may vary, but the order does not. This is a strong empirical claim that the journey metaphor makes seem natural — of course you cannot skip stages on a journey. But cognitive development need not work this way, and the metaphor’s apparent obviousness obscures the need for evidence.

• Qualitative distinctness — the “stage” in theatrical usage is a distinct performance space. Each act is not just “more” of the previous one; it is a different scene with different dynamics. Piaget maps this onto cognition: a preoperational child does not merely know less than a concrete-operational child; the child thinks differently. Conservation of quantity is not a piece of information the preoperational child lacks but a structural capacity the child’s cognitive apparatus cannot yet perform. The stage metaphor makes this radical claim — that there are qualitative discontinuities in thought — seem intuitive.

• Stages as platforms — each stage provides a stable platform from which the next stage is constructed. The journey metaphor includes this: each town provides the provisions for the next leg. Piaget’s stages work analogously: sensorimotor intelligence (action-based knowing) provides the raw material that preoperational intelligence (symbolic representation) reorganizes at a higher level. Each stage both transcends and includes the previous one. The metaphor of staged ascent — staircase, ladder, journey upward — runs through all of Piaget’s writing.

• Universal path, individual pace — the journey metaphor allows for travelers who move at different speeds but follow the same route. Piaget maps this onto his claim that while the ages associated with each stage vary across individuals and cultures, the sequence is universal. This universalist claim was central to Piaget’s project of grounding epistemology in biology rather than culture.

Limits

• Development is not domain-general — the journey metaphor places the whole child at one stage. Empirical research since the 1970s has consistently shown that children can be at different “stages” in different cognitive domains simultaneously. A child might demonstrate conservation of number before conservation of volume. Neo-Piagetian theories (Case, Fischer) replaced the single-path journey with multiple parallel developmental pathways, each with its own trajectory.

• Transitions are not clean — a journey passes through towns; you are either in one town or the next. Piaget acknowledged transitional periods, but the stage metaphor constantly pulls toward sharp boundaries. In reality, children oscillate between stage-characteristic behaviors, sometimes showing formal-operational reasoning in one context and concrete-operational reasoning in another within the same testing session. The stage metaphor erases this variability.

• The endpoint is culturally loaded — journeys have destinations, and Piaget’s journey ends at formal operational thought: abstract, hypothetico-deductive reasoning. This positions Western academic cognition as the developmental telos. Cross-cultural research has shown that many adults in non-Western societies do not demonstrate formal operational thinking on Piaget’s tests — not because they are “developmentally delayed” but because the tests measure a culturally specific form of reasoning that the stage metaphor frames as the universal endpoint.

• The staircase discourages regression — stages go up. The metaphor implies that development is monotonically increasing: once you reach a stage, you do not go back. But cognitive regression is well-documented — under stress, fatigue, or in unfamiliar domains, adults routinely exhibit “earlier” forms of reasoning. The stage metaphor has no room for this because you cannot un-travel a journey. This limitation has practical consequences in education, where teachers may assume that a demonstrated competence is permanent.

Expressions

• “What stage are they at?” — diagnostic question in education, importing the journey metaphor’s assumption of ordered waypoints
• “Age-appropriate” — assumes developmental stages aligned with age ranges, a direct descendant of Piaget’s stage theory
• “They’re not ready for that yet” — stage-based reasoning about instructional sequencing
• “Stages of grief” (Kubler-Ross) — transferred the stage metaphor from cognitive development to emotional processing
• “Stages of team development” (Tuckman) — forming, storming, norming, performing: the stage metaphor applied to group dynamics
• “At that stage of their career” — professional development borrowing the developmental-journey framing

Origin Story

Piaget’s stage theory developed gradually through decades of meticulous observation, beginning with his own three children in the 1920s and extending through thousands of clinical interviews at the University of Geneva. The four-stage model crystallized in The Psychology of the Child (1966, with Barbel Inhelder) and became the dominant framework in developmental psychology through the 1970s. The stage metaphor proved irresistibly generative: Kohlberg applied it to moral development, Erikson to psychosocial development, Fowler to faith development, and Tuckman to group dynamics. By the 1980s, the stage metaphor had become so pervasive that critics began questioning whether “stage” was describing a real feature of development or imposing a structure on continuous change. The neo-Piagetian movement (Case, Fischer, Halford) retained Piaget’s constructivism while abandoning the strict stage architecture.

References

• Piaget, J. and Inhelder, B. The Psychology of the Child (1966/1969)
• Piaget, J. The Origins of Intelligence in Children (1936/1952)
• Case, R. The Mind’s Staircase (1992) — neo-Piagetian stage theory
• Fischer, K. “A Theory of Cognitive Development: The Control and Construction of Hierarchies of Skills” in Psychological Review (1980)
• Lourenco, O. and Machado, A. “In Defense of Piaget’s Theory” in Psychological Review (1996)