Meagan's economics professor argues that people are optimal decision makers. her psychology professor argues that people are often irrational decision makers. her economics professor believes in a model of human decision making; her psychology professor believes in a model.

I believe the answer is: normative; descriptive
The normative model of human decision making would assume that every decision would be based on the principle of right or wrong.
Descriptive model of human decision making on the other hand would be based on the options that would be the most applicable under that specific situation.