Tuesday, February 04, 2020

Piaget (1896-1980) – Bad scientist… mostly wrong…

Jean Piaget, the Swiss psychologist, claimed that cognitive development proceeds in four genetically determined stages, and that they always follow the same order. This theory of child development, he called ‘genetic epistemology’, and it saw the minds of children as very different from those of adults. Importantly, this perception must be taken into account in teaching and learning. Big problem – he got it mostly wrong.

Four ‘ages and stages’

1. Sensorimotor (0-2) Intelligence takes form of motor actions.
2. Preoperational (3-7) Intelligence intuitive in nature.
3. Concrete operations (8-11) Intelligence logical but needs concrete referents.
4. Formal operations (12-15) Thinking involves abstractions.
Each of these stages had a more granular structure, which Piaget explored in some detail. His emphasis on mathematical and analytic task experimentation has been criticized as being a little narrow. However, this, he saw as a good indicator of general cognitive development.

Famous four-stages demolished

His famous four stage developmental model  has been fairly well demolished.
First, the Sensimotor Stage with the infamous ‘hide a toy under a cloth and the child thinks it’s no longer there’ study, which turned out to be an exercise in distraction, and when repeated by Bower and Wishart in the absence of an adult, with a teddy, most children had no difficulty in understanding that the toy is still under the cloth. In general, Piaget simply focused too much on motor actions when the real development is perceptual. Kagan also attributes object permanence to a simple increase in memory capacity.
Second, the Pre-operational Stage study, where a child fails to recognise a doll’s point of view from photographs of three mountains, was shown to be too complex for the children to understand. A simpler experiment by Hughes, using dolls of two policemen, showed that many children can understand non-egocentric perspectives.
Third, the Concrete Operation Stage was refuted by Rose and Blank, when it was found that Piaget had been verbally correcting the children towards his wanted conclusions, invalidating the data. The ‘naughty teddy’ experiment also wiped out his famous three rows of sweets trial supposedly showing that kids couldn’t get constancy in number. Overall he ignored hereditary, educational and cultural effects, thereby standardising theory, when, in fact, there are large differences in the speed and nature of development due to these and other factors
Fourthly, the Formal Operative Stage focused too much on formal logic, ignoring many other mature cognitive skills. It’s as if we were all little mathematicians, not ‘little scientists’. In fact kids develop, not in a predictable, linear fashion, but in fits and starts, and in many different ways.
All in all, his four stages were abandoned as subsequent research showed that development takes place much earlier than he had posited, is more of a continuum, with more variation in ages and more plasticity than was previously thought.

Poor scientist

How did he get it so wrong? Well, like Freud, he was no scientist. First, he used his own three children (or others from wealthy, professional families) and not objective or multiple observers to eliminate observational bias. Secondly, he often repeated a statement if the child’s answer did not conform to his experimental expectation. Thirdly, the data and analysis lacked rigour, making most of his supposed studies next to useless. So, he led children towards the answers he wanted, didn’t isolate the tested variables, used his own children, and was extremely vague on his concepts.


Is there much, or anything, that is useful in Piaget to a teacher? His four-stage theory of child development has been so completely negated by subsequent studies, that it’s merely an exercise in the history of science. Piaget was the dominant force in child psychology but many of his claims are now subject to a critique from Bruner, Vygotsky, other constructivists and other developmental psychologists, who see a more malleable developmental picture. What is worrying is the fact that this Piagean view of child development, based on 'ages and stages' is still widely believed, despite being quite wrong. This leads to misguided teaching methods. Education and training is still soaked in this dated theory. However, on the whole, his sensitivity to age and cognitive development did lead to a more measured and appropriate use of educational techniques that matched the true cognitive capabilities of children.


Piaget, J. (1929). The Child's Conception of the World. NY: Harcourt, Brace Jovanovich.
Piaget, J. (1932). The Moral Judgement of the Child. NY: Harcourt, Brace Jovanovich.
Piaget, J. (1969). The Mechanisms of Perception. London: Rutledge & Kegan Paul.
Paiget, J. (1970). The Science of Education and the Psychology of the Child. NY: Grossman.
Piaget, J. & Inhelder, B. (1969). The Psychology of the Child. NY: Basic Books.
Piaget, J. & Inhelder, B. (1973). Memory and intelligence. NY: Basic Books.
Bybee, R.W. & Sund, R.B. (1982). Piaget for Educators (2nd Ed). Columbus, OH: Charles Merrill.
Jean Piaget Society

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