There were challenges that moral maturity as measured by Kohlbergian instruments is reflecting personal preference rather than conceptual capacity. In the present study, junior high school students were asked to fake high (or fake low) in the Defining Issues Test (DIT) of moral development by pretending as someone with high.(or low) principles of justice. Results showed that faking high was impossible, which lends further credence to Kohlberg's cognitive view of moral development. It was also pointed out that the analyses of both the ranking and rating scores might help to clarify the test-taking or response-set behavior in the use of the DIT.