Extinction: This term does not refer to the fate of dinosaurs, but to the disappearance of a link between the conditioned stimulus and the conditioned response. Imagine a third variation on the conditioning “story” described above. Suppose, as I suggested above, that the child begins by associating your happy behaviors” your smiles to his being present in the classroom, so that the classroom itself becomes enough to elicit his own smiles. But now suppose there is a sad turn of events: you become sick and must therefore leave the classroom in the middle of the school year. A substitute is called in who is not Mr Horrible, but simply someone who is not very expressive, someone we can call Ms Neutral. At first the child continues to feel good (that is, to smile) whenever present in the classroom. But because the link between the classroom and your particular smile is no longer repeated or associated, the child's response gradually extinguishes, or fades until it has disappeared entirely. In a sense the child's initial learning is “unlearned”.
Extinction can also happen with negative examples of classical conditioning. If Mr Horrible leaves midyear (perhaps because no one could stand working with him any longer!), then the child's negative responses (cringing, eyes widening, heart beat racing, and so on) will also extinguish eventually. Note, though, that whether the conditioned stimulus is positive or negative, extinction does not happen suddenly or immediately, but unfolds over time. This fact can sometimes obscure the process if you are a busy teacher attending to many students.
Generalization: When Pavlov studied conditioning in dogs, he noticed that the original conditioned stimulus was not the only neutral stimulus that elicited the conditioned response. If he paired a particular bell with the sight of food, for example, so that the bell became a conditioned stimulus for salivation, then it turned out that other bells, perhaps with a different pitch or type or sound, also acquired some ability to trigger salivation though not as much as the original bell. Psychologists call this process generalization, or the tendency for similar stimuli to elicit a conditioned response. The child being conditioned to your smile, for example, might learn to associate your smile not only with being present in your classroom, but also to being present in other, similar classrooms. His conditioned smiles may be strongest where he learned them initially (that is, in your own room), but nonetheless visible to a significant extent in other teachers' classrooms. To the extent that this happens, he has generalized his learning. It is of course good news; it means that we can say that the child is beginning to learn to like school” in general, and not just your particular room. Unfortunately, the opposite can also happen: if a child learns negative associations from Mr Horrible, the child's fear, caution, and stress might generalize to other classrooms as well. The lesson for teachers is therefore clear: we have a responsibility, wherever possible, to make classrooms pleasant places to be.
Discrimination: Generalization among similar stimuli can be reduced if only one of the similar stimuli is associated consistently with the unconditioned response, while the others are not. When this happens, psychologists say that discrimination learning has occurred, meaning that the individual has learned to distinguish or respond differently to one stimulus than to another. From an educational point of view, discrimination learning can be either desirable or not, depending on the particulars of the situation. Imagine again (for the fourth time!) the child who learns to associate your classroom with your smiles, so that he eventually produces smiles of his own whenever present in your room. But now imagine yet another variation on his story: the child is old enough to attend middle school, and therefore has several teachers across the day. You with your smiles are one, but so are Mr Horrible and Ms Neutral. At first the child may generalize his classically conditioned smiles to the other teachers' classrooms. But the other teachers do not smile like you do, and this fact causes the child's smiling to extinguish somewhat in their rooms. Meanwhile, you keep smiling in your room. Eventually the child is smiling only in your room and not in the other rooms. When this happens, we say that discrimination has occurred, meaning that the conditioned associations happen only to a single version of the unconditioned stimuli in this case, only to your smiles, and not to the (rather rare) occurrences of smiles in the other classrooms. Judging by his behavior, the child is making a distinction between your room and others.
In one sense the discrimination in this story is unfortunate in that it prevents the child from acquiring a liking for school that is generalized. But notice that an opposing, more desirable process is happening at the same time: the child is also prevented from acquiring a generalized dislike of school. The fear-producing stimuli from Mr Horrible, in particular, become discriminated from the happiness-producing smiles from you, so the child's learns to confine his fearful responses to that particular classroom, and does not generalize them to other “innocent” classrooms, including your own. This is still not an ideal situation for the student, but maybe it is more desirable than disliking school altogether.
- 瀏覽次數：3763
