Higher-Order Conditioning and Blocking
Blocking in Classical Conditioning
Generalization, Discrimination, Extinction, and Spontaneous Recovery
Conversely, through discrimination the brain learns to differentiate between stimuli that do and do not signal the onset of the unconditioned stimulus. For example, a firecracker may explode only after a blue light flashes but never after a white light flashes. The blue light will elicit the startle reflex, but the white light will not because the brain has learned to distinguish between events that follow the lights.
In the extinction phase, the conditioned stimulus is presented alone repeatedly—without the unconditioned stimulus—until the conditioned stimulus loses its power to elicit the conditioned response. In other words, the conditioned stimulus returns to a neutral stimulus. If the flashing blue light (conditioned stimulus) is presented repeatedly without the firecracker, eventually it will no longer trigger a startle response.After the conditioned response has been extinguished, it sometimes spontaneously reoccurs. If a person does not see a flashing blue light for a period of time, they may flinch when they see it again. This happens because the original learned association between the light and firecracker never fully disappears.
Opponent Process Theory of Addiction
If an environment presents drug-related cues but the drug is not taken, people with addiction problems will experience withdrawal symptoms—for example, shaking, sweating, insomnia, and irritability. People can show physical signs of withdrawal years after kicking their habit when asked to perform their drug "cooking up" procedure. Watching a videotape of heroin preparation can have the same effect. Former alcoholics report intense cravings and evidence withdrawal symptoms when they enter bars. This is why it is much easier for people to overcome addiction in new environments, such as drug rehabilitation centers. The cues aren't there, so the cravings subside. But when they return to cue-rich environments, the cravings return, making relapse more likely.
Fetishes and Phobias to Neutral Stimuli
People can develop phobias if an experience causes them to associate a neutral stimulus with a fear-inducing stimulus. For example, a person may develop a phobia of eating after a choking experience. The first scientific demonstration of acquired phobias was conducted by American psychologist John B. Watson and his assistant Rita Raynor. Watson and Raynor induced a phobia to a white rat in an 11-month-old infant (nicknamed Little Albert). They did this by striking a hammer on a steel bar whenever the rat was presented to the infant. Prior to this pairing, Albert showed that he liked playing with the rat. After the pairings, Albert cried and attempted to crawl away whenever the rat was presented. Albert's fear generalized to other similar stimuli, including the family dog, a fur coat, some cotton wool, and a Santa Claus mask.
Practical Applications of Classical Conditioning
Aversion therapy has been used to target drug and alcohol abuse, overeating, smoking, gambling, and compulsive nail biting. For example, a drug called Antabuse blocks the breakdown of alcohol. If people take this drug before drinking, consuming alcohol will lead to nausea. Eventually, even just smelling or tasting alcohol will make people feel nauseous. People who want to stop biting their nails may paint a spicy or foul-tasting substance on their nails. Other aversive stimuli used have included unpleasant odors or images and even mild electrical shock. While aversion therapy has proved successful in many cases, it remains controversial. By necessity, it involves inflicting some level of physical or emotional pain during the therapeutic process.
Classical conditioning often underlies advertisements used to increase sales. Ads often display products in ways that highlight features that naturally elicit feelings of desire. For example, a fast-food ad may show close-up, vivid pictures of appetizing food (US) that trigger feelings of hunger (UR). At the same time, viewers are repeatedly shown the company's logo (CS). Over time, simply seeing the logo (now a CR) may cause people to experience hunger and desire. The result is that the viewer is more likely to purchase the product.