So it is far from a simple mechanical reaction. That huge brain wasn't added to your spinal cord for nothing. Perhaps, if the subjects had been told and shown that it was impossible for the drug to be administered again, the fear response to the light would have declined rapidly. Also, if the light had been presented many times before the drug was administered, the reaction to the light may have been easier to extinguish. Science is just beginning to learn more about how cognitions interact with conditioning.
Cognitive methods are a new tool for expanding self-control in many areas.
Some fears are unreasonable and harmful, some are reasonable and helpful, e.g. the anorexic's totally unreasonable fear of food making her fat and the heart attack victim's reasonable and helpful fear of high fat food. In time, the anorexic can change her mind about her body and the person with a heart condition can forget to watch his diet. There are many other mysteries about fears. New conditioning theories help explain these things. Many people are afraid of snakes or mice but have never been bitten.