Student or Learner
What is "act out" here"? "make performance like in a play" or "show or express your emotion"? Is it a common expression?
ex)Role theory takes the view that consumer behavior resembles actions in a play. As people act out different roles, they sometimes alter their consumption decisions depending on the "play" they are in. The criteria that they use to evaluate products and services in one of their roles may be quite different from those used in another role. In many cases, the purchaser and the user of a product might....
The second definition that you've given refers to behavior that is not in accordance with accepted norms, such as a teenager standing on a seat on a bus or an employee berating his supervisor in public.