There is some evidence that the ________ system in the brain may be the source of unconscious motivations, in support of Freud's theory

Emily suffers from insomnia. When she went to see a doctor, she was told that her sleeplessness was caused by the deficiency of a particular hormone. The doctor then gave her sleeping pills containing the deficient hormone. Emily has _____ deficiency

A) melatonin B) thyroxin C) vasopressin D) oxytocin

Instrumental conditioning is another name for:

a. operant conditioning b. classical conditioning c. second-order conditioning d. higher-order conditioning