Are Lawrence Kohlberg's stages of moral development supported by empirical evidence? I've just come across a (very basic) description of Kohlberg's stages of moral development, and I found the section on the Pre-conventional level of moral reasoning rather suprising.
In particular, stage one, obedience and punishment orientation:

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.
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. &quot;The last time I did that I got spanked so I will not do it again.&quot; The worse the punishment for the act is, the more &quot;bad&quot; the act is perceived to be. This can give rise to an inference that even innocent victims are guilty in proportion to their suffering. It is &quot;egocentric&quot;, lacking recognition that others' points of view are different from one's own.There is &quot;deference to superior power or prestige&quot;

What surprised me is the example of moral perception in relation to degree of punishment.
While there does seem to be support for the idea (please feel free to chime in on that question with more authoritative answers!) that spanking can be an effective means of eliminating undesireable behavior, there is a significant amount of evidence citing the general levels of negative impact corporal punishment can have.
Anecdotally, lower levels of punishment seem to have no correlation with Kohlberg's Stage One model.  My son does not seem to equate punishment as indication that an action is 'morally wrong'.  He does understand that if he repeats the behavior, he will likely have to repeat the punishment, but given the experimentations with defiance and self-assertion common to three year olds, he does tend to repeat the behavior at least a few times, in an attempt to push boundaries and see what he can get away with.
Additionally, the one time my son has been exposed to corporal punishment (another child's grandmother decided to spank her son in daycare, right in front of my son, much to my anger and frustration), my son showed no indication that he felt that the boy had done anything wrong, but rather was obsessively concerned as to whether he was okay, and why she would do that to him.
This seems counter to the idea that the punishment instills the idea that the actions which precipitate the punishments are &quot;morally wrong&quot;, as Kohlberg seems to be asserting.
Am I misunderstanding Kohlberg's Stage One?  Is his theory generally considered reputable?  Most importantly, is there observational data upon which his theory is based, which supports the conclusions he draws?
Kohlberg constucted his stages of moral development using a sample consisting of 72 boys from Chicago. The sample consisted of three age groups: 10, 13 and 16 years. This was also the start for a 30-year long lasting longitudinal study to test his theory (Colby, Kohlberg, Gibbs &amp; Lieberman, 1983). The results generally support the theory. Younger children are classified as belonging to the lower stages, older children as belonging to the higher stages of moral development. Differences between stages become smaller as one goes up the hierarchy. Also, age differences between stages become smaller with higher stages.

But there also appears to be some criticism. First, there were only few subjects in some of the age groups of the study. Second, apparently Kohlberg has quite often revised his theory and reformulated the descriptions for the stages, and it is not always clear which version was used for testing. Some critics have therefore argued that Kohlberg has "immunized" his theory against falsification. This point also has to do with criticism regarding the assesment of the moral stage, which was done using the Standard Issue Moral Judgement Test, an interview developed by Kohlberg. 

Everything I have said so far is taken from Heidbrink (1991), who has tested the theory using a different test, the Morals Judgment Test by Lind. His study supports Kohlbergs's stages. Among over 1000 subjects between ages 14-29, only two showed a pattern that is not consistent with the theory.

In a re-analysis of a study from 1913 – 45 years before Kohlberg's first relevant publication and thus free of the suspicion of having jumped on the "Kohlberg bandwagon" –, Heidbrink (1989) finds that the results conform to those of Colby &amp; Kohlberg's longitudinal study (1987). He concludes that the fact that American adolescents of the 1950s and 60s show the same moral development as pupils from Berlin before the First World War supports Kohlberg's hypothesis of the universal validity of his stages of moral development.

If you want to go further, the Wikipedia article on Kohlberg's stages has a long list of references that you can look at. Probably some of those review the relevant research. Also try to input Kohlberg's own articles or books into Google Scholar and click the "Cited by" link to see which other articles deal with this theory, there will be empirical studies among those.

After collecting all the information to answer your question, I have to say that I am also a bit surprised about the example chosen to describe stage one. The example caters to very young children, while youngest boys in Kohlberg's study were 10 years old. Maybe we shouldn't focus too much on this example. Right off the bat I don't have a better example, but I could imagine there is one. 

References: 

I used German publications. If someone has English references, please help me out here.


Colby, A., Kohlberg, L., Gibbs, J., &amp; Lieberman, M. (1983). A longitudinal study of moral judgment. Monographs of the Society for Research in Child Development, 48 (Serial No. 200), 1-124. University of Chicago Press.
Heidbrink, H. (1989). Moralpsychologie: Die Reanalyse einer Untersuchung von 1913. Geschichte der Psychologie, 6, 4-9. Available online at http://journals.zpid.de/index.php/GdP/article/view/424/459
Heidbrink, H., &amp; Lück, H. E. (1991). Stufen der Moral: Zur Gültigkeit der kognitiven Entwicklungstheorie Lawrence Kohlbergs. Quintessenz-Verl.