Which of the following is an example of external (subjective) factor which affect attention?

Classical conditioning (Pavlov): Neutral stimulus paired with unconditioned stimulus to produce conditioned response (involuntary).
Operant conditioning (Skinner): Voluntary behavior shaped by consequences (reinforcement/punishment).

Typical options include:
a. Child gets dessert for cleaning room (operant: positive reinforcement).
b. Dog salivates to bell after food pairing (classical: conditioned response).
c. Rat presses lever for food (operant: positive reinforcement).
d. Gold star for homework (operant: positive reinforcement).

Only option b demonstrates stimulus-stimulus association leading to involuntary response, without voluntary action required.

** b **