From a response contingent viewpoint, which of the following tells a person or an animal that a response was "right" and worth repeating?

Neuroleptics work primarily by inhibiting the activity of which neurotransmitter?

a) serotonin b) dopamine c) epinephrine d) norepinephrine

The following is true of Hull's laws:

a. They only involved relationships of certainty. b. He referred to them as postulates. c. Each law could easily be tested for validity. d. Hull's system did not contain laws.