Kohlberg and Piaget: Differences and Similarities

Iordanis Kavathatzopoulos. Journal of Moral Education. Volume 20, Issue 1. 1991.

Kohlberg’s cognitive-stage-developmental theory is often described as a further development of Piaget’s moral theory. In discussing the two theories, it is shown that Kohlberg attempts to describe the features of moral thought and not the formation of the independent moral function. Nevertheless, Kohlberg’s later research, as well as research done by his disciples, approaches Piaget. In trying to study the issue of moral education in ‘just communities, they reintroduce the Piagetian concept of cooperation in equality among the members of the group, and they use a collaborator or leader. However, their main interest remains in the description of the characteristics of the stages of individual moral reasoning and valuing of norms and community, and not the study of the process of acceleration towards the autonomous moral phase.


Kohlberg’s theory is said to be not only influenced by Piaget’s theory of moral autonomy, but it is often described as a further development of that theory. However, there are some doubts about the relationship of the two theories. First, there are differences in major theoretical issues, for example their constructivistic nature, as well as in the methods used. These, in turn, have serious implications for empirical issues such as the universality hypothesis, the thought-action problem and for moral education.

Theoretical Aspects

Kohlberg (1981, 1984) describes moral development as a sequence of six, or at least, five stages (since he could not find empirical support for the existence of Stage Six). The development is understood as a movement to higher more abstract and universal moral principles which regulate the moral thinking and action of the individual. This development unfolds in an invariant manner and the stages, which are structured wholes, are hierarchically related to each other. The philosophical basis for this stage sequence is Platonic. The individual tends towards an ideal form of moral thinking: the discovery of the principle of ‘justice’.

If we compare this to Piaget (1932, 1976, 1978, 1980), we find an interesting difference. Piaget’s theory is first and foremost a constructivistic theory. That means that each individual’s moral structures are constructed by him while he is acting upon the social world he lives in. It is unlikely that this process can lead to universal reasoning, i.e. the same moral content or principles to follow, because as the social conditions and relations vary in different cultures, so do action and thinking. Thus, if Kohlberg insists on being a constructivist, the achievement of Kohlbergian universality is unlikely, in contrast to Piagetian universality. The latter does not imply the discovery of specific moral content or principle. Instead, Piagetian universality, which is in essence Spinozian, is constructed through logical and scientific processes, the adoption of which is necessary in order to serve the true nature of man (Spinoza, 1983). Kohlberg asserts that the development of moral thinking unfolds through a universal sequence which leads to the discovery of universal moral principles. If so, it is very difficult to see how such a theory can be compatible with constructivism.

This problem has its origin in Kohlberg’s (1981) attempt to derive ‘Ought’ from ‘Is’. In order to do that he was forced to reject relativity and claim that the sequence of moral development is universal and independent of culture. But, in addition to the accusation that he is influenced by the values of his own society (Emler, 1983), he is described as an ethical realist (Vine, 1983).

Of course, it is not necessary to become an ethical realist in order to avoid ethical relativism. But for Kohlberg it is impossible to do this, since his theory is not immune to relativism. If we substitute the principle of justice with some other principle, i.e. change the content of the principle, other things being equal, we may still be able to find the same formal features in the actual stage. Hence only a recourse to realism can protect Kohlberg from absolute relativism.

On the other hand, Piaget, thanks to the Spinozian nature of his constructivistic theory, does not encounter this problem. Piaget needs neither realism or relativism, since in his effort to adapt to the social world the individual has to take into consideration both his nature and the reality of the world. That implies that it is impossible for different individuals living in different societies to construct an unlimited variety of moral concepts and principles, since the nature of man is supposed to remain the same both geographically and historically. Human cultures and societies also share many common structural and functional features. Of course, this does not imply ethical realism. The individual constructs moral concepts driven by his nature and social factors, many of which are common to different cultures. He is not discovering pre-existing principles, as Kohlberg claims.

This has certain implications for the autonomy issue. Piaget understands moral development as a construction process, i.e. the interplay of action and thought builds moral concepts. Kohlberg on the other hand, describes development as a process of discovering universal moral principles. In the first case autonomy means allowing this process to unfold independently. But it is hard to ascertain what autonomy means to Kohlberg. Probably it means independence from other principles or content of moral reasoning. Piaget’s moral theory as well as his cognitive theory describe processes of operations which produce knowledge. In contrast, Kohlbergian moral reasoning at each stage does not produce any new knowledge. The individual has only to follow an imperative, which, of course, is different at each stage. The focus of Kohlberg’s research is on the description of the different forms thought takes in appealing to these imperatives of moral principles.

These theoretical differences have some implications for the methods used by the two theories. The Piagetian theory studies the process of the formation of moral concepts and actions. That process is necessary for the individual in order to adapt to the social world. Piaget does not differentiate between action and thinking. Both are part of the same process. Therefore the method used takes into consideration both action and thinking, e.g. the marble game. The Piagetian stories are also related to action, since they focus on instrumental social concepts such as ‘intention’ and ‘equality’. Kohlberg, on the other hand, is interested in the description of the characteristics of moral development towards the discovery of universal principles. Thus, only hypothetical stories are used, which are sufficient to cause cognitive conflict in the subject’s mind. The subjects’ motivations for their answers to this conflict are the ground on which the Kohlbergian theory rests. The relationship of the stories to the subject’s life, or to his actions, are not taken into consideration. That is the origin of the thought-action problem.

The Thought-Action Problem

The thought-action problem has been discussed widely. Kurtines & Greif (1974) criticised Kohlberg’s theory in that there is low predictive validity of moral action from moral thought, but their review regarded the theory as a psychometric model (Broughton, 1978). Blasi’s (1980) review supported Kohlberg but it revealed some problems in the relationship between moral reasoning and moral action, and as a solution he proposed the adoption of the hypothesis of responsibility. Furthermore, the rationalistic and ethical realistic theory of Kohlberg does not take into consideration the role of action for the formation of thought, which it should do if it were a constructivistic theory (Emler, 1983; Locke, 1983a,b; Wright, 1983). However, Kohlberg attempted to solve this problem without studying the thought-action dimension.

Kohlberg proposed first the notion of ego-strength (Kohlberg, 1969) and later the theory that higher-stage subjects are more consistent in their actions, by making a distinction between deontic and responsibility judgements. Following Blasi’s (1980) and Gilligan’s (1977) criticisms he introduced the division of the stages into two sub-stages: Type A and Type B (Kohlberg & Candee, 1984; Kohlberg et al., 1984). In doing that Kohlberg attempted to find out the typology of Piaget’s two phases of moral development. Although Piaget did not define these phases as Kohlberg does, Kohlberg identifies Type A with heteronomy and Type B with autonomy. By reviewing some classical studies he showed that the actions of Type B individuals were more consistent with their moral reasoning than the actions of Type A individuals. Kohlberg defines the differences between these two types as a difference in formal features, such as universalisability, prescriptivity, reversibility and generality, and in the presence or not of the feeling of responsibility. Type B individuals often feel more responsible for carrying out their deontic judgements. Even so, this theory has been criticised in that it does not differentiate between judgemental and motivational choices (Straughan, 1985).

Thus, in attempting to solve the thought-action problem, Kohlberg attempts a new approach to Piaget. He perceives the value of Piaget’s two phases of moral functioning, although this hypothesis is very different from the nature of his own theory. Of course this does not mean that Kohlberg changes his theory. It means only that the thought-action problem compels him to start seeking for a solution in the theory of Piaget.

The Issue of Moral Education

However, the most interesting development in Kohlberg’s theory towards Piaget has taken place in the area of moral education. Previously Kohlberg studied the hierarchical movement from stage to stage by using the classical method of dilemmas (Rest, Turiel & Kohlberg, 1969; Turiel, 1966; Turiel & Rothman, 1972). The same method was used in classroom discussions where the teacher presented and clarified one-stage-above moral reasoning to the students (Blatt & Kohlberg, 1975).

In that early approach to moral education various ways to influence development were studied. But that influence was supposed to affect only the transition from a lower to a higher stage on Kohlberg’s stage scale, and on the developmental process from concrete to abstract thinking. That developmental dimension denotes the theory’s rationalism in contrast to Piagetian constructivism. The disequilibrium was not caused by the individual’s interaction with reality but purely through a cognitive conflict. Therefore, the developmental process was not supposed to have any functional dimension. The distinction between content and structure was understood as a certain stage’s content and structure, and it was adopted in order to explain the isolated cognitive conflict. Structure did not mean the underlying organisation or hierarchy of the cognitive knowledge producing processes, but rather a kind of content which was more general, more stable, and deeper: the Kohlbergian scheme, i.e. the structure of the content. Moral cognitive function was understood as the production of thoughts patterned after the underlying structure, which may be called internal heteronomy. Even the notion of responsibility, adopted later as an answer to the thought-action problem, emphasises the theory’s focus on the ways of following moral principles than the production processes of moral knowledge.

According to Kohlberg, moral cognitive function was not a way (automatic or scientific) of producing cognitive content and its structure. Structural changes occurred by shifting from stage to stage, but this mode of change, besides being rational (not caused by a confrontation with reality), seems to be an automatic process that neither demands man’s consciousness and logical reason, nor his activity, in order for that change to occur. Dialogue alone with another person does not imply any confrontation with reality since this dialogue is about hypothetical stories. On the other hand, in a Piagetian setting, the dialogue among peers is taking place in a real situation and it is about problems which, besides being real, are of great importance for the members of the group. That earlier theory of Kohlberg did not allow the study of autonomous, logical and scientific thinking, versus automatic and heteronomous thinking, in a social setting meaningful for the individual.

Later, Kohlberg approached the issue of moral education in a different way. He studied the influence of moral atmosphere upon the formation and following of new rules. Indeed, he found significant differences between democratic and traditional schools. The results showed that the students in the democratic schools rated higher than the traditional high school students in their judgements concerning hypothetical as well as practical dilemmas; they showed a higher frequency of responsibility judgements and pro-social choice for themselves and others. Furthermore, the students in the democratic schools possessed a higher degree of the collectiveness of norms and of community valuing, such as a higher phase of the collective norm (Higgins et al., 1984; Kohlberg, 1985; Power et al., 1989).

What is interesting about the democratic school is not only the acquisition of these characteristics, but also the formulation of new rules in that ‘just community’. The moral atmosphere of the group is very important for the establishment of equality and cooperation among the individual members. Even so, the understanding of the spirit and the aims of the community, as well as the intervention by an instructor are necessary for the formation of new, more functional rules.

… my role in community meetings, and the role which I strove to teach the staff, was to speak not for myself but as representing the spirit, traditions and future of the community. In this spirit I would (1) advocate making a rule or developing a collective norm important to the school and (2) attempt to tie this norm to the welfare and spirit of community of the group. (Kohlberg, 1985,p.46)

That spirit is understood as the nucleus of a special community, the deeper cause of the construction of this community, and the aim of its existence. Thus the main problems that a community or a social group encounters are related to that spirit. Consequently the understanding of this relationship by the members of the group or community is necessary in order to find the most functional solutions to these problems by the formulation and acceptance of appropriate rules.

It is obvious then that this later Kohlbergian mode of theorising approaches Piaget. First and foremost, the introduction of the problematic of the formulation of new rules, but also the significance of moral atmosphere, i.e. equality and cooperation, and the role played by a ‘collaborator’, are sufficient to show this new Kohlbergian tendency.

Indeed, the most important aspect of this change is the theory that the creation of disequilibrium, which is necessary for the formulation of new moral rules by cooperating individuals in a democratic/egalitarian community, is possible, through pointing to the spirit of that same community by a collaborator/instructor, and the subsequent understanding or internalisation of that by the members of the community.

Kohlberg and Piaget

However, this tardy approach to the essential Piaget does not imply any rejection of the Kohlbergian theory accepted up to that time. Kohlberg and his followers are still interested in the stage advancement of morality. Their research is focused on the characteristics of this stage development and on the stages of the individual moral reasoning and valuing of norms and community. The Kohlbergians are interested primarily in the features of community where the formulation of new rules is taking place, and not on the thought formation process itself, i.e. the action-thought direction. It seems that this rule formulation process is used only as a mean for the understanding and explanation of the stage characteristics of moral thinking and community valuing. Piaget, on the contrary, is primarily interested in the thought formation process itself, while the characteristics of this process have a secondary value.

Even Piaget’s theory of development towards moral autonomy allows instruction to play a positive role. Based on Vygotsky’s (1962, 1978) criticism of Piaget’s theory of cognitive development, the conclusion is reached that instruction can accelerate development towards the phase of moral autonomy. Indeed, two empirical studies of the concepts of ‘intention’ and ‘equality’ showed that simple instructions stimulated a significant shift to the higher phase of moral judgement (Kavathatzopoulos, 1988).

Still, there is a difference between Kohlberg and Piaget regarding the goal of moral education. Although Kohlberg mentions the spirit of the community as a very important factor for the formulation of new moral rules, the stage development which he presents does not lead to a principle of justice (representing the spirit of community) as Piaget (1932) understands it, i.e. as equality and independence, but to the high, abstract, universal and rational Kohlbergian ‘justice’.


Kohlberg’s later research on moral education approaches Piaget. Then Kohlberg adopted the problematic of the formulation of new moral rules by the adapted and functional moral thinking processes of cooperating individuals. He even accepted the positive influence of a collaborator. Nevertheless, Kohlbergians did not abandon their theory, which continues to focus research on the description of the features of the stage development of moral thinking towards the discovery of the principle of justice.