Thaddeus Is a Graduate Student in a Health Psychology Program

Thaddeus is a graduate student in a health psychology program. He decides that for his dissertation project he is going to replicate one of his advisor's studies but extend the original hypothesis. Instead of just investigating the role of exercise as a risk factor in the development of heart disease, he wants to examine how much exercise is optimally beneficial for longevity of life. To do so, he examines both the quantity and intensity of the exercise for each participant. Which of the following strategies is Thaddeus using to develop a good hypothesis?

A) finding the exception to the rule
B) thinking about variables in a matter of degree
C) utilizing introspection
D) changing the directionality