* This is termed “Pavlovian conditioning” in a nod to Ivan Pavlov; it’s the same process by which Pavlov’s dogs learned to associate the conditioned stimulus of a bell with the unconditioned stimulus of food, so that the former eventually was able to provoke salivation. Less reliable are “operant conditioning” approaches, in which the degree to which something is scary is assessed by how much an individual will work to avoid being exposed to it.
