Whose study described the differences in the way that boys and girls view morality?

Carl Gilligan.

Explanation:

Carl Gilligan is an American developmental psychologist who contributed to the field of ethical community and relationships and also an originator of ethics of care.

In her book "In a Different Voice: Psychological Theory and Women's Development" she spoke about the gender differences criticizing the work of Kohlberg's moral development. Her book reveals the differences in the ways boys and girls view morality.

So, the correct answer is Carl Gilligan.