Piaget's stages of cognitive development
Four stages of reasoning: sensorimotor (infancy), preoperational (early childhood, egocentric and intuitive), concrete operational (logical about tangible things) and formal operational (abstract, hypothetical, systematic).
What drives it
Useful for identification in adults because formal reasoning is neither universal nor stable: many adults reason concretely in unfamiliar domains, and under stress most people slide back towards concrete, egocentric thinking.
How it shows
Work
Concrete reasoners want examples and struggle with "what if" scenarios and abstract strategy; formal reasoners hold hypotheses, test them, think in systems. Under anxiety a sophisticated thinker turns egocentric ("they did this to me") and literal. Adult egocentrism shows in presentations pitched only from the speaker's point of view.
Relationships
Under emotional stress: magical thinking ("If I'd called, he wouldn't have been in the accident"), egocentrism and black-and-white judgements.
Self
Notice when your reasoning narrows under pressure: you lose the ability to hold a hypothetical or see the situation from the other side.
What tells it apart
Erikson's psychosocial stages: Erikson tracks the emotional and social question a person is working on; Piaget tracks logical capacity. Someone can reason abstractly and still be stuck on trust.
Ego development (Loevinger): Ego development tracks the complexity of understanding self and others; a strong formal reasoner can still hold a simple, self-protective view of people.
A test
Pose a hypothetical ("Suppose our biggest client left; what would we do first?") and watch whether the person works the hypothesis or drifts back to the concrete present.
Questions to carry
- Given a hypothetical, how long does the person stay with it before drifting back to the present?
- Under pressure, where does my thinking shrink to the concrete and to me?
How strong the research is
moderate. The broad sequence holds, but children show abilities earlier than Piaget thought, development is less stage-like, and formal operations are neither universal nor consistent across domains.
Where it comes from
Jean Piaget, 1920s to 1950s; with Bärbel Inhelder, 1950s
On the family tree: Jean Piaget