To gauge a child’s developmental level, it is important that the method of gauging doesn’t rely on the child’s verbal abilities - this biases in favor of older children. One’s verbal skill may grow at a different pace from the skill you are measuring.
Turiel designed a study where the students merely had to answer “Yes” or “No”. This avoids the verbal ability bias.
He posed various scenarios to the the students, like:
Johnny wears regular clothes to a school that has a uniform policy.
- Did he do wrong? Yes
- What if the teacher said his behavior was OK? Not wrong.
- What if he went to a school with no uniform policy? Also not wrong.
Jill wants to play on a swing in school. Currently a boy is on the swing. She pushes him off to play with it.
- Did she do wrong? Yes
- What if the teacher said her behavior is OK? Still wrong.
- What if the school has no rules about this? Still wrong.
The difference between the two scenarios: The kids recognize one as a social convention and the other as an issue of morality. This distinction was found in all cultures that were studied.
The basic rule seemed to be: Harm is wrong. If harm is involved, it is a moral issue, not a mere convention.
By 1987, Kohlberg and Turiel had defined the field of moral psychology.