Jean Piaget (August 9, 1896 – September 16, 1980) was a Swiss philosopher, natural scientist and developmental theorist, well known for his work studying children, his theory of cognitive development and for his epistemological view called "genetic epistemology."
The very great importance he attached to the education of children made him declare in 1934 in his role as Director of the International Bureau of Education that ‘only education is capable of saving our societies from possible collapse, whether violent, or gradual’.
In 1955 he created the International Centre for Genetic Epistemology in Geneva and directed it until 1980. According to Ernst von Glasersfeld, Jean Piaget is "the great pioneer of the constructivist theory of knowing.
Piaget was born in 1896 in Neuchâtel in the French-speaking part of Switzerland. His father, Arthur Piaget, was a professor of medieval literature
at the University of Neuchâtel. Piaget was a precocious child who developed an interest in biology and the natural world, particularly molluscs
, and even published a number of papers before he graduated from high school. In fact, his long career of scientific research began when he was just eleven, with the 1907 publication of a short paper on the albino sparrow
. Over the course of his career, Piaget wrote more than sixty books and several hundred articles.
Piaget received a Ph.D
. in natural science from the University of Neuchâtel
, and also studied briefly at the University of Zürich
. During this time, he published two philosophical papers which showed the direction of his thinking at the time, but which he later dismissed as adolescent work. His interest in psychoanalysis
, a strain of psychological thought burgeoning at that time, can also be dated to this period.
He then moved from Switzerland to Paris, France, where he taught at the Grange-Aux-Belles street school for boys run by Alfred Binet, the developer of the Binet intelligence test. It was while he was helping to mark some instances of these intelligence tests that Piaget noticed that young children consistently gave wrong answers to certain questions. Piaget did not focus so much on the fact of the children's answers being wrong, but that young children kept making the same pattern of mistakes that older children and adults did not. This led him to the theory that young children's thought or cognitive processes are inherently different from those of adults. (Ultimately, he was to propose a global theory of developmental stages stating that individuals exhibit certain distinctive common patterns of cognition in each period in their development.) In 1921, Piaget returned to Switzerland as director of the Rousseau Institute in Geneva.
In 1923, he married Valentine Châtenay, one of his students; together, the couple had three children, whom Piaget studied from infancy. In 1929, Jean Piaget accepted the post of Director of the International Bureau of Education and remained the head of this international organization until 1968. Every year, he drafted his “Director's Speeches” for the IBE Council and for the International Conference on Public Education in which he explicitly expressed his educational credo.
The stages of cognitive development
Also the 'Four levels of development', these are (1) infancy, (2) preschool, (3) childhood, and (4) adolescence. Each stage is characterized by a general cognitive structure that affects all of the child's thinking (a structuralist
view influenced by philosopher Immanuel Kant
). Each stage represents the child's understanding of reality during that period, and each but the last is an inadequate approximation of reality. Development from one stage to the next is thus caused by the accumulation of errors in the child's understanding of the environment; this accumulation eventually causes such a degree of cognitive disequilibrium that thought structures require reorganizing.
The four development stages are described in Piaget's theory as:
- Sensorimotor stage: from birth to age 2. Children experience the world through movement and senses (use five senses to explore the world). During the sensorimotor stage children are extremely egocentric, meaning they cannot perceive the world from others viewpoints and explore using senses. The sensorimotor stage is divided into six substages: "(1) simple reflexes; (2) first habits and primary circular reactions; (3) secondary circular reactions; (4) coordination of secondary circular reactions; (5) tertiary circular reactions, novelty, and curiosity; and (6) internalization of schemes."
Simple reflexes is from birth to 1 month old. At this time infants use reflexes such as rooting and sucking.
First habits and primary circular reactions is from 1 month to 4 months old. During this time infants learn to coordinate sensation and two types of scheme (habit and circular reactions). A primary circular reaction is when the infant tries to reproduce an event that happened by accident (ex: sucking thumb).
The third stage, secondary circular reactions, occurs when the infant is 4 to 8 months old. At this time they become aware of things beyond their own body; they are more object oriented. At this time they might accidentally shake a rattle and continue to do it for sake of satisfaction.
Coordination of secondary circular reactions is from 8 months to 12 months old. During this stage they can do things intentionally. They can now combine and recombine schemes and try to reach a goal (ex: use a stick to reach something). They also understand object permanence during this stage. That is, they understand that objects continue to exist even when they can't see them.
The fifth stage occurs from 12 months old to 18 months old. During this stage infants explore new possibilities of objects; they try different things to get different results.
During the last stage they are 18 to 24 months old. During this stage they shift to symbolic thinking. During the sensorimotor stage children are extremely egocentric, meaning they cannot perceive the world from others viewpoints and explore using senses.
- Preoperational stage: from ages 2 to 7 (magical thinking predominates. Acquisition of motor skills) Egocentricism begins strongly and then weakens. Children cannot conserve or use logical thinking.
- Concrete operational stage: from ages 7 to 11 (children begin to think logically but are very concrete in their thinking) Children can now conserve and think logically but only with practical aids. They are no longer egocentric.
- Formal operational stage: after age 11 (development of abstract reasoning). Children develop abstract thought and can easily conserve and think logically in their mind.
The developmental process
Piaget provided no concise description of the development process as a whole. Broadly speaking it consisted of a cycle:
- The child performs an action which has an effect on or organizes objects, and the child is able to note the characteristics of the action and its effects.
- Through repeated actions, perhaps with variations or in different contexts or on different kinds of objects, the child is able to differentiate and integrate its elements and effects. This is the process of reflecting abstraction (described in detail in Piaget 2001).
- At the same time, the child is able to identify the properties of objects by the way different kinds of action affect them. This is the process of empirical abstraction.
- By repeating this process across a wide range of objects and actions, the child establishes a new level of knowledge and insight. This is the process of forming a new cognitive stage. This dual process allows the child to construct new ways of dealing with objects and new knowledge about objects themselves.
- However, once the child has constructed these new kinds of knowledge, he or she starts to use them to create still more complex objects and to carry out still more complex actions. As a result, the child starts to recognize still more complex patterns and to construct still more complex objects. Thus a new stage begins, which will only be completed when all the child's activity and experience have been re-organized on this still higher level.
This process is not wholly gradual, however. Once a new level of organization, knowledge and insight proves to be effective, it will quickly be generalized to other areas. As a result, transitions between stages tend to be rapid and radical, and the bulk of the time spent in a new stage consists of refining this new cognitive level. When the knowledge that has been gained at one stage of study and experience leads rapidly and radically to a new higher stage of insight, a "gestalt" is said to have occurred.
It is because this process takes this dialectical form, in which each new stage is created through the further differentiation, integration, and synthesis of new structures out of the old, that the sequence of cognitive stages are logically necessary rather than simply empirically correct. Each new stage emerges only because the child can take for granted the achievements of its predecessors, and yet there are still more sophisticated forms of knowledge and action that are capable of being developed.
Because it covers both how we gain knowledge about objects and our reflections on our own actions, Piaget's model of development explains a number of features of human knowledge that had never previously been accounted for. For example, by showing how children progressively enrich their understanding of things by acting on and reflecting on the effects of their own previous knowledge, they are able to organize their knowledge in increasingly complex structures. Thus, once a young child can consistently and accurately recognize different kinds of animals, he or she then acquires the ability to organize the different kinds into higher groupings such as ‘birds’, ‘fish’, and so on. This is significant because they are now able to know things about a new animal simply on the basis of the fact that it is a bird – for example, that it will lay eggs.
At the same time, by reflecting on their own actions, the child develops an increasingly sophisticated awareness of the ‘rules’ that govern in various ways. For example, it is by this route that Piaget explains this child's growing awareness of notions such as ‘right’, ‘valid’, ‘necessary’, ‘proper’, and so on. In other words, it is through the process of objectification, reflection and abstraction that the child constructs the principles on which action is not only effective or correct but also justified.
One of Piaget's most famous studies focused purely on the discriminative abilities of children between the ages of two and a half years old, and four and a half years old. He began the study by taking children of different ages and placing two lines of M&M's, one with the M&M's in a line spread further apart, and one with the same number of M&M's in a line placed more closely together. He found that, “Children between 2 years, 6 months old and 3 years, 2 months old correctly discriminate the relative number of objects in two rows; between 3 years, 2 months and 4 years, 6 months they indicate a longer row with fewer objects to have "more"; after 4 years, 6 months they again discriminate correctly” (Cognitive Capacity of Very Young Children, p. 141). Initially younger children were not studied, because if at four years old a child couldn’t conserve quantity, how could a child that is younger? The results show however that children that are younger than three years and two months have quantity conservation, but as they get older they lose this quality, and don’t recover it until four and a half years old. This attribute may be lost due to a temporary inability to solve because of an overdependence on perceptual strategies, which correlates more candy with a longer line of candy, or due to the inability for a four year old to reverse situations.
By the end of this experiment several results were found. First, younger children have a discriminative ability that shows the logical capacity for cognitive operations exists earlier than acknowledged. This study also reveals that young children can be equipped with certain qualities for cognitive operations, depending on how logical the structure of the task is. Research also shows that children develop explicit understanding at age 5 and as a result, the child will count the M&M's to decide which has more. Finally the study found that overall quantity conservation is not a basic characteristic of man's native inheritance.
Piaget's theory, however vital in understanding child psychology, did not go without scrutiny. A main figure in the ratification of Piaget's ideas was the Russian psychologist Lev Vygotsky
. Vygotsky stressed the importance of a child's cultural background as an effect to the stages of development. Because different cultures stress different social interactions, this challenged Piaget's theory that the hierarchy of learning development had to develop in succession. Vygotsky introduced the term zone of proximal development
as an over all task a child would have to develop that would be too difficult to develop alone.
According to Jean Piaget, genetic epistemology
"attempts to explain knowledge, and in particular scientific knowledge, on the basis of its history, its sociogenesis, and especially the psychological origins of the notions and operations upon which it is based.
Jean Piaget has become a reference for epistemology, and particularly for constructivist epistemology.
Recently, Jonathan Tsou argued that Piaget's later epistemological works could serve as a remedy for the flaws in Thomas Kuhn's theory of scientific revolutions. However, this criticism missed some of the history between them, as well as the existence of a "lost manuscript" by Kuhn (currently held at the University of Chicago) that was to address his critics' concerns. It is noted, however, that the implications of his later work remain largely unexamined.
Despite ceasing to be a fashionable psychologist
, the magnitude of Piaget's continuing influence can be measured by the global scale and activity of the Jean Piaget Society
, which holds annual conferences and attracts very large numbers of participants. His theory of cognitive development
has proved influential in many different areas:
Piaget is without doubt one of the most influential developmental psychologists, influencing not only the work of Lev Vygotsky
and of Lawrence Kohlberg
but whole generations of eminent academics. Although subjecting his ideas to massive scrutiny led to innumerable improvements and qualifications of his original model and the emergence of a plethora of neo-Piagetian and post-Piagetian variants, Piaget's original model has proved to be remarkably robust (Lourenço and Machado 1996).
Education and development of morality
During the 1970s and 1980s, Piaget's works also inspired the transformation of European and American education
, including both theory and practice, leading to a more ‘child-centred’ approach. In Conversations with Jean Piaget,
he says: "Education, for most people, means trying to lead the child to resemble the typical adult of his society . . . but for me and no one else, education means making creators. . . . You have to make inventors, innovators—not conformists" (Bringuier, 1980, p.132).
Mainly, Piaget influenced two parts of education: early education and moral education.
In early education, teachers use his theory of cognitive development as a tool in the classroom. According to Piaget, children developed best in a classroom with interaction. Using this idea, teachers in elementary schools or pre-school can make use of classroom time better using peer interaction.
In moral education, Piaget believed in two basic principles. The first one is the fact that children develop moral ideas in stages. The other is that children make their idea of the world: "The child is someone who constructs his own moral world view, who forms ideas about right and wrong, and fair and unfair, that are not the direct product of adult teaching and that are often maintained in the face of adult wishes to the contrary" (Gallagher, 1978, p.26). The idea is that children observe the world, and then decide what is morally correct. So in today's education, we have started to bring moral education into education, such as talking about cheating and what is morally correct in today's society, dealing with crime and morals in politics.
Piaget's theory of morality was radical in 1932 when his book, The Moral Judgment of the Child, was published, due to his use of philosophical criteria to define morality (as universalizable, generalizable, and obligatory), and his rejection of equating cultural norms and moral norms. Piaget, drawing on Kantian theory, proposed that morality developed out of peer interaction, and that it was autonomous from authority mandates. Peers, not parents, were a key source of moral concepts, such as equality, reciprocity, and justice.
In his account of the development of moral judgment Piaget (1932) introduced a fundamental distinction between different types of social relationship, or more specifically he attributed different types of psychosocial processes to different forms of social relationship. Where there is constraint because one participant holds more power than the other the relationship is asymmetrical, and, importantly, the knowledge that can be acquired by the dominated participant takes on a fixed and inflexible form. Piaget refers to this process as one of social transmission, and he refers to the way in which the elders of a tribe initiate younger members into the patterns of beliefs and practices of the group. Similarly where adults exercise a dominating influence over the growing child, it is through social transmission that children can acquire knowledge. By contrast, in cooperative relations, power is more evenly distributed between participants so that a more symmetrical relationship emerges. Under these conditions authentic forms of intellectual exchange become possible, since each partner has the freedom to project his or her own thoughts, consider the positions of others, and defend his or her own point of view. In such circumstances, where children’s thinking is not limited by a dominant influence, the conditions exist for the emergence of constructive solutions to problems, or what Piaget refers to as the reconstruction of knowledge rather than social transmission. Here the knowledge that emerges is open, flexible and regulated by the logic of argument rather than being determined by an external authority. In short, cooperative relations provide the arena for the emergence of operations, which for Piaget requires the absence of any constraining influence, and is most often illustrated by the relations that form between peers (for more on the importance of this distinction see Duveen & Psaltis, in press; Psaltis & Duveen, 2006,2007).
Historical studies of thought and cognition
Historical changes of thought have been modeled in Piagetian terms. Broadly speaking these models have mapped changes in morality, intellectual life and cognitive levels against historical changes (typically in the complexity of social systems).
Notable examples include:
Neo-Piagetian stages have been applied to the maximum stage attained by various animals. For example spiders attain the circular sensory motor stage, coordinating actions and perceptions. Pigeons attain the sensory motor stage, forming concepts.
The origins of human intelligence have also been studied in Piagetian terms. Wynn (1979, 1981) analysed Acheulian and Oldowan tools in terms of the insight into spatial relationships required to create each kind. On a more general level, Robinson's Birth of Reason (2005) suggests a large-scale model for the emergence of a Piagetian intelligence.
Piaget's models of cognition have also been applied outside the human sphere, and some primatologists assess the development and abilities of primates in terms of Piaget's model.
Some have taken account of Piaget's work. For example, the philosopher
and social theorist Jürgen Habermas
has incorporated Piaget into his work, most notably in The Theory of Communicative Action.
The philosopher Thomas Kuhn
credited Piaget's work in helping him understand the transition between modes of thought which characterized his theory of paradigm shifts
. Shortly before his death (October 1975), Piaget was involved in a debate about the relationships between innate and acquired features of language, at the Centre Royaumont pour une Science de l'Homme, where he discussed his point of view with the linguist Noam Chomsky
as well as Hilary Putnam
and Stephen Toulmin
Piaget also had a considerable effect in the field of computer science
and artificial intelligence
. Seymour Papert
used Piaget's work while developing the Logo programming language
. Alan Kay
used Piaget's theories as the basis for the Dynabook
programming system concept, which was first discussed within the confines of the Xerox Palo Alto Research Center, or Xerox PARC
. These discussions led to the development of the Alto
prototype, which explored for the first time all the elements of the graphical user interface
(GUI), and influenced the creation of user interfaces in the 1980s and beyond.
Major works and achievements
- Piaget, J. (1950). Introduction à l’Épistémologie Génétique. Paris: Presses Universitaires de France.
- Piaget, J. (1961). La psychologie de l'intelligence. Paris: Armand Colin (1961, 1967, 1991). Online version
- Piaget, J. (1967). Logique et Connaissance scientifique, Encyclopédie de la Pléiade.
- Inhelder, B. and J. Piaget (1958). The Growth of Logical Thinking from Childhood to Adolescence. New York: Basic Books.
- Inhelder, B. and Piaget, J. (1964). The Early Growth of Logic in the Child: Classification and Seriation. London: Routledge and Kegan Paul.
- Piaget, J. (1928). The Child's Conception of the World. London: Routledge and Kegan Paul.
- Piaget, J. (1932). The Moral Judgment of the Child. London: Kegan Paul, Trench, Trubner and Co.
- Piaget, J. (1952). The Child's Conception of Number. London: Routledge and Kegan Paul.
- Piaget, J. (1953). The Origins of Intelligence in Children. London: Routledge and Kegan Paul.
- Piaget, J. (1955). The Child's Construction of Reality. London: Routledge and Kegan Paul.
- Piaget, J. (1971). Biology and Knowledge. Chicago: University of Chicago Press.
- Piaget, J. (1995). Sociological Studies. London: Routledge.
- Piaget, J. (2001). Studies in Reflecting Abstraction. Hove, UK: Psychology Press.
- Beth, E.W., and Piaget, J. (1966). Mathematical Epistemology and Psychology. Dordrecht: D. Reidel.
- Piaget, J. (1942). Les trois structures fondamentales de la vie psychique: rythme, régulation et groupement. Rev. Suisse de Psychologie Appliquée, 1/2 9–21.
- Piaget, J. (1948). Où va l’éducation? UNESCO.
- Piaget, J. (1951). Psychology of Intelligence. London: Routledge and Kegan Paul
- Piaget, J. (1953). Logic and Psychology. Manchester: Manchester University Press.
- Piaget, J. (1962). Play, Dreams and Imitation in Childhood. New York: Norton.
- Piaget, J. (1966). Nécessité et signification des recherches comparatives en psychologie génétique. Journal International de Psychologie, 1 (1): 3-13.
- Piaget, J. (1970). Structuralism. New York: Harper & Row.
- Piaget, J. (1972). Psychology and Epistemology: Towards a Theory of Knowledge. Harmondsworth: Penguin.
- Piaget, J. (1972). Insights and Illusions of Philosophy. London: Routledge and Kegan Paul.
- Piaget, J. (1974). Experiments in Contradiction. Chicago: University of Chicago Press.
- Piaget, J. (1974). The Place of the Sciences of Man in the System of Sciences. New York: Harper and Row, Publishers.
- Piaget, J. (1975). The Origin of the Idea of Chance in Children. London: Routledge and Kegan Paul.
- Piaget, J. (1977). The Grasp of Consciousness. London: Routledge and Kegan Paul.
- Piaget, J. (1978). Success and Understanding. London: Routledge and Kegan Paul.
- Piaget, J. (1979). Behaviour and Evolution. London: Routledge and Kegan Paul.
- Piaget, J. (1980). Adaptation and Intelligence. London: University of Chicago Press.
- Piaget, J. (1980). Les Formes Élémentaires de la Dialectique. Paris, Editions Gallimard.
- Piaget, J. (1981). Intelligence and Affectivity. Their Relationship during Child Development. Palo Alto: Annual Reviews.
- Piaget, J. (1983). Piaget's theory. In P. Mussen (ed.). Handbook of Child Psychology. 4th edition. Vol. 1. New York: Wiley.
- Piaget, J. (1985). The Equilibration of Cognitive Structures: The Central Problem of Intellectual Development. Chicago: University of Chicago Press.
- Piaget, J. (1987). Possibility and Necessity. 2 vols. Minneapolis: University of Minnesota Press.
- Piaget, J. (2000). Commentary on Vygotsky. New Ideas in Psychology, 18, 241-59.
- Piaget, J., and Garcia, R. (1989). Psychogenesis and the History of Science. New York: Columbia University Press.
- Piaget, J., and Garcia, R. (1991). Towards a Logic of Meanings. Hillsdale, N.J.: Lawrence Erlbaum Associates.
- Piaget, J., and Inhelder, B. (1962). The Psychology of the Child. New York:Basic Books
- Piaget, J., and Inhelder, B. (1967). The Child's Conception of Space. New York: W.W. Norton.
- 1921-25 Research Director, Institut Jean-Jacques Rousseau, Geneva
- 1925-29 Professor of Psychology, Sociology and the Philosophy of Science, University of Neuchatel
- 1929-39 Professor of the History of Scientific Thought, University of Geneva
- 1929-67 Director, International Bureau of Education, Geneva
- 1932-71 Director, Institute of Educational Sciences, University of Geneva
- 1938-51 Professor of Experimental Psychology and Sociology, University of Lausanne
- 1939-51 Professor of Sociology, University of Geneva
- 1940-71 Professor of Experimental Psychology, University of Geneva
- 1952-64 Professor of Genetic Psychology, Sorbonne, Paris
- 1955-80 Director, International Centre for Genetic Epistemology, Geneva
- 1971-80 Emeritus Professor, University of Geneva
Piagetian and post-Piagetian stage theories
- "Intelligence is what you use when you don't know what to do."
- "Intelligence organizes the world by organizing itself.
- The principle goal of education in the schools should be creating men and women who are capable of doing new things, not simply repeating what other generations have done.
- Aqueci, F. (2003). Ordine e trasformazione: morale, mente, discorso in Piaget. Acireale-Roma: Bonanno. ISBN 8877961481.
- Amann-Gainotti, M., & Ducret, J.-J. (1992). Jean Piaget, disciple of Pierre Janet: Influence of behavior psychology and relations with psychoanalysis. Information Psychiatrique, 68, 598-606.
- Beilin, H. (1992). Piaget's enduring contribution to developmental psychology. Developmental Psychology, 28, 191-204.
- Bringuier, J.-C. (1980). Conversations with Jean Piaget (B.M. Gulati, Trans.). Chicago: University of Chicago Press. (Original work published 1977) ISBN 0226075036.
- Chapman, M. (1988). Constructive evolution: Origins and development of Piaget's thought. Cambridge: Cambridge University Press. ISBN 0521367123.
- Commons, M. L., Goodheart, E. A., Pekker, A., Dawson, T.L., Draney, K., & Adams, K. M. (2008). Using Rasch Scaled Stage Scores To Validate Orders of Hierarchical Complexity of Balance Beam Task Sequences. Journal of Applied Measurement, 9(2),
- Duveen, G. & Psaltis, C. (in press). The constructive role of asymmetries in social interaction. In U. Mueller, J. I. M. Carpendale, N. Budwig & B. Sokol (Eds.), Social life and social knowledge: Toward a process account of development. Mahwah, NJ: Lawrence Erlbaum.
- Flavell, J. (1967). The developmental psychology of Jean Piaget. New York: D. Van Nostrand Company. ISBN 0442024134.
- Fowler, J. W. (1981). Stages of faith: The psychology of human development and the quest for meaning. San Francisco: Harper & Row. ISBN 0-06-062866-9.
- Gattico, E. (2001). Jean Piaget. Milano: Bruno Mondadori. ISBN 884249741X.
- Hallpike, C.R. (1979). The foundations of primitive thought. Oxford: Oxford University Press. ISBN 0198231962.
- Ivey, A. (1986). Developmental therapy. San Francisco: Jossey-Bass. ISBN 1555420222.
- Kamii, C. (1985). Young children reinvent arithmetic: Implications of Piaget's theory. New York: Teachers College Press.
- Kesselring, T. (1999). Jean Piaget. München: Beck. ISBN 3406445128.
- Kassotakis, M. & Flouris, G. (2006) Μάθηση & Διδασκαλία, Αthens.
- Kitchener, R. (1986). Piaget's theory of knowledge: Genetic epistemology & scientific reason. New Haven: Yale University Press. ISBN 0300035799.
- Lourenço, O. and Machado, A. (1996). In defense of Piaget's theory: A reply to ten common criticisms. Psychological Review, 103, 143–164.
- Messerly, J.G. (1992). Piaget's conception of evolution: Beyond Darwin and Lamarck. Lanham, MD: Rowman & Littlefield. ISBN 0847682439.
- Psaltis, C., & Duveen, G. (2006). Social relations and cognitive development: The influence of conversation type and representations of gender. European Journal of Social Psychology, 36, 407-430.
- Psaltis, C. & Duveen, G. (2007). Conversation types and conservation: Forms of recognition and cognitive development. British Journal of Developmental Psychology, 25, 79-102.
- Robinson, R.J. (2005). The birth of reason. Prometheus Research Group. (Available online at http://www.prometheus.org.uk)
- Smith, L. (Ed.) (1992). Jean Piaget: Critical assessments (4 Vols.). London: Routledge. ISBN 0415044081.
- Smith, L. (1993). Necessary knowledge: Piagetian perspectives on constructivism. Hove, UK: Lawrence Erlbaum. ISBN 0863772706.
- Smith, L. (Ed.) (1996). Critical readings on Piaget. London: Routledge. ISBN 0415133173.
- Smith, L. (2001). Jean Piaget. In J. A. Palmer (Ed.), 50 modern thinkers on education: From Piaget to the present. London: Routledge.
- Vidal, F. (1994). Piaget before Piaget. Cambridge, MA: Harvard University Press. ISBN 0674667166.
- Vonèche, J.J. (1985). Genetic epistemology: Piaget's theory. In T. Husén & T.N. Postlethwaite (Eds.-in-chief), International encyclopedia of education (Vol. 4). Oxford: Pergamon.
- Wynn, T. (1979). The intelligence of later Acheulean hominids. Man (ns), 14, 371–391.
- Wynn, T. (1981). The intelligence of Oldowan hominids. Journal of Human Evolution, 10, 529–541.