Pam has a history of taking an antidepressant, Zoloft, to decrease negative thoughts and increase her mood and affect. The Zoloft was prescribed to her by her psychiatrist. Zoloft pills contain sertraline, which is the drug that automatically results in fewer depressive symptoms. One week, her psychiatrist decides to change Pam's medication, but doesn't tell Pam. The psychiatrist decides to replace her antidepressants with a placebo - a pill that looks exactly like her typical antidepressants, but only has sugar inside of it (i.e., there is no drug / sertraline in the pill). Despite receiving a placebo, Pam still experiences decreased negative thoughts and still has an increased mood and affect. Is this an example of classical / Pavlovian or higher-order conditioning?

1. Higher-order conditioning
2. Classical conditionaing
3. Pavlovian conditioning