What tells you more about a persons motivations: what they say they believe or how they behave?

A lot of people say they believe one thing, but they don’t behave as if that belief motivates their actions. So what is going on? What is the relationship between beliefs and actions, in your view of personality?

Do you think that what a person says they believe is a good guide to their behavior? Or do you think beliefs are not all that relevant in understanding a person’s motivations?

Please give examples if possible and explain why you think what you think.