Lawrence Kohlberg's stages of moral development constitute an adaptation of a psychological theory originally conceived of by the Swiss psychologist Jean Piaget. Kohlberg began work on this topic while a psychology postgraduate student at the University of Chicago^[1] in 1958, and expanded and developed this theory throughout his life.
The theory holds that moral reasoning, the basis for ethical behavior, has six identifiable developmental stages, each more adequate at responding to moral dilemmas than its predecessor.^[2] Kohlberg followed the development of moral judgment far beyond the ages studied earlier by Piaget,^[3] who also claimed that logic and morality develop through constructive stages.^[2] Expanding on Piaget's work, Kohlberg determined that the process of moral development was principally concerned with justice, and that it continued throughout the individual's lifetime,^[4] a notion that spawned dialogue on the philosophical implications of such research.^[5][6]
For his studies, Kohlberg relied on stories such as the Heinz dilemma, and was interested in how individuals would justify their actions if placed in similar moral dilemmas. He then analyzed the form of moral reasoning displayed, rather than its conclusion,^[6] and classified it as belonging to one of six distinct stages.^[7][8][9]
There have been critiques of the theory from several perspectives. Arguments include that it emphasizes justice to the exclusion of other moral values, such as caring;^[10] that there is such an overlap between stages that they should more properly be regarded as separate domains; or that evaluations of the reasons for moral choices are mostly post hoc rationalizations (by both decision makers and psychologists studying them) of essentially intuitive decisions.^[11]
Nevertheless, an entirely new field within psychology was created as a direct result of Kohlberg's theory, and according to Haggbloom et al.'s study of the most eminent psychologists of the 20th century, Kohlberg was the 16th most frequently cited psychologist in introductory psychology textbooks throughout the century, as well as the 30th most eminent overall.^[12]
Kohlberg's scale is about how people justify behaviors and his stages are not a method of ranking how moral someone's behavior is. There should however be a correlation between how someone scores on the scale and how they behave, and the general hypothesis is that moral behaviour is more responsible, consistent and predictable from people at higher levels.^[13]

Contents 1 Stages 1.1 Pre-conventional 1.2 Conventional 1.3 Post-Conventional 1.4 Further stages 2 Theoretical assumptions (philosophy) 2.1 Formal elements 3 Examples of applied moral dilemmas 3.1 Heinz dilemma 4 Criticisms 5 Continued relevance 6 See also 7 References 8 Further reading The pre-conventional level of moral reasoning is especially common in children, although adults can also exhibit this level of reasoning. Reasoners at this level judge the morality of an action by its direct consequences. The pre-conventional level consists of the first and second stages of moral development, and is solely concerned with the self in an egocentric manner. A child with preconventional morality has not yet adopted or internalized society's conventions regarding what is right or wrong, but instead focuses largely on external consequences that certain actions may bring.[7][8][9] In Stage one (obedience and punishment driven), individuals focus on the direct consequences of their actions on themselves. For example, an action is perceived as morally wrong because the perpetrator is punished. "The last time I did that I got spanked so I will not do it again." The worse the punishment for the act is, the more "bad" the act is perceived to be.[16] This can give rise to an inference that even innocent victims are guilty in proportion to their suffering. It is "egocentric", lacking recognition that others' points of view are different from one's own.[17] There is "deference to superior power or prestige".[17] Stage two (self-interest driven) espouses the "what's in it for me" position, in which right behavior is defined by whatever is in the individual's best interest. Stage two reasoning shows a limited interest in the needs of others, but only to a point where it might further the individual's own interests. As a result, concern for others is not based on loyalty or intrinsic respect, but rather a "You scratch my back, and I'll scratch yours." mentality.[2] The lack of a societal perspective in the pre-conventional level is quite different from the social contract (stage five), as all actions have the purpose of serving the individual's own needs or interests. For the stage two theorist, the world's perspective is often seen as morally relative. Conventional The conventional level of moral reasoning is typical of adolescents and adults. Those who reason in a conventional way judge the morality of actions by comparing them to society's views and expectations. The conventional level consists of the third and fourth stages of moral development. Conventional morality is characterized by an acceptance of society's conventions concerning right and wrong. At this level an individual obeys rules and follows society's norms even when there are no consequences for obedience or disobedience. Adherence to rules and conventions is somewhat rigid, however, and a rule's appropriateness or fairness is seldom questioned.[7][8][9] In Stage three (interpersonal accord and conformity driven), the self enters society by filling social roles. Individuals are receptive to approval or disapproval from others as it reflects society's accordance with the perceived role. They try to be a "good boy" or "good girl" to live up to these expectations,[2] having learned that there is inherent value in doing so. Stage three reasoning may judge the morality of an action by evaluating its consequences in terms of a person's relationships, which now begin to include things like respect, gratitude and the "golden rule". "I want to be liked and thought well of; apparently, not being naughty makes people like me." Desire to maintain rules and authority exists only to further support these social roles. The intentions of actors play a more significant role in reasoning at this stage; "they mean well ...".[2] In Stage four (authority and social order obedience driven), it is important to obey laws, dictums and social conventions because of their importance in maintaining a functioning society. Moral reasoning in stage four is thus beyond the need for individual approval exhibited in stage three. A central ideal or ideals often prescribe what is right and wrong, such as in the case of fundamentalism. If one person violates a law, perhaps everyone would—thus there is an obligation and a duty to uphold laws and rules. When someone does violate a law, it is morally wrong; culpability is thus a significant factor in this stage as it separates the bad domains from the good ones. Most active members of society remain at stage four, where morality is still predominantly dictated by an outside force.[2] Post-Conventional