一。Classical Conditioning
Classical conditioning is a type of learning in which a stimulus acquires the capacity to evoke a
response that was originally evoked by another stimulus.
1.What Pavlov had demonstrated was how learned associations—which were viewed as the basic building blocks of the entire learning process—were formed by events in an organism’s environment.
2.Terminology and Procedures
熟练掌握UCR,UCS,CS,CR概念，常有选择题是关于某种现象是属于UCR,UCS,CS,CR只中的那一种的。
The unconditioned stimulus (UCS) is a stimulus that evokes an unconditioned response without previous conditioning.
The unconditioned response (UCR) is an unlearned reaction to an unconditioned stimulus that occurs without previous conditioning.
The conditioned stimulus (CS) is a previously neutral stimulus that has, through conditioning, acquired the capacity to evoke a conditioned response.
The conditioned response (CR) is a learned reaction to a conditioned stimulus that occurs because of previous conditioning.
3.A trial in classical conditioning consists of any presentation of a stimulus or pair of stimuli.
 
Research in recent decades has demonstrated that classical conditioning is involved in a wider range of human and animal behavior than previously appreciated,including some types of nonreflexive responding

Classical Conditioning in Everyday Life
一下是一些日常生活中经典条件反射的实例：
1.Conditioned Fears
  看书上例子，触类旁通，如果考试有选择题涉及类似反应，就好分析了。
2.Other Conditioned Emotional Responses
  Classical conditioning is not limited to producing unpleasant emotions such as fear. Many pleasant emotional responses are also acquired through classical conditioning.
  广告中经常用到classical conditioning，
Advertisers frequently pair their products with UCSs that elicit pleasant emotions。
3.Conditioning and Physiological Responses
  Classical conditioning affects not only overt behaviors but physiological processes as well.
 例子1：  your body’s immune functioning----classical conditioning procedures can lead to immunosuppression—a decrease in the production of antibodies.
  In a typical study, animals are injected with a drug (the UCS) that chemically causes
immunosuppression while they are simultaneously given an unusual-tasting liquid to drink (the CS).
（这个例子更多描写在书上接下来的文字，注意这里就有标注的UCS,CS等，必须学会分清给定实例中的UCR,UCS,CS,CR）
例子2：classical conditioning can also elicit allergic reactions
例子3：classical conditioning contributes to the growth of drug tolerance and the experience of withdrawal symptoms when drug use is halted。
例子4：classical conditioning can influence sexual arousal
     具体描写在本小节最后一段

前面对Classical Conditioning下了定义，又给出了一些实例，下面就要对Classical Conditioning过程具体分析：
Basic Processes in Classical Conditioning
1.Acquisition: Forming New Responses
Acquisition refers to the initial stage of learning something.

Pavlov theorized that the acquisition of a conditioned response depends on stimulus contiguity, or the occurrence of stimuli together in time and space.

contiguity alone doesn’t automatically produce conditioning。

Evidence suggests that stimuli that are novel, unusual, or especially intense have more potential
to become CSs than routine stimuli, probably because they are more likely to stand out among other
stimuli (Hearst, 1988).

2.Extinction:Weakening Conditioned Responses
The right circumstances produce extinction, the gradual weakening and disappearance of a conditioned response tendency.

What leads to extinction in classical conditioning?
The consistent presentation of the conditioned stimulus alone, without the unconditioned stimulus.

How long does it take to extinguish a conditioned response? That depends on many factors, but particularly important is the strength of the conditioned bond when extinction begins.

3.Spontaneous Recovery:Resurrecting Responses：
Spontaneous recovery is the reappearance of an extin-guished response after a period of nonexposure to the conditioned stimulus.
书上有一个巴普洛夫观察狗分泌唾液所得这一现象的实验细节描写。

extinction suppresses or interferes with a conditioned response rather than erasing a learned association (Bouton & Nelson, 1998).
Spontaneous Recovery may also help explain why people who manage to give up cigarettes, drugs, or poor eating habits for a while may experience a relapse and return to their unhealthy habits (Bouton, 2000).

4.Stimulus Generalization and the Case of Little Albert：
Stimulus generalization occurs when an organism that has learned a response to a specific stimulus responds in the same way to new stimuli that are similar to the original stimulus.
书上有对 Little Albert做的Stimulus Generalization 实验，通过white rat和大噪声配对使 Little Albert
对white rat产生恐惧，而且还发现他对许多类似的刺激也会产生恐惧，including a rabbit, a dog, a fur coat, a Santa Claus mask, and Watson’s hair.
The basic law governing generalization is this: The more similar new stimuli are to the original CS, the greater the generalization.

5.Stimulus Discrimination：
Stimulus discrimination occurs when an organism that has learned a response to a specific stimulus does not respond in the same way to new stimuli that are similar to the original stimulus.

Like generalization, discrimination is adaptive in that an animal’s survival may hinge on
its being able to distinguish friend from foe, or edible from poisonous food (Thomas, 1992).

As with generalization, a basic law governs discrimination: The less similar new stimuli are to the original CS, the greater the likelihood (and ease) of discrimination.

6.Higher-Order Conditioning：
Higher-order conditioning, in which a conditioned stimulus functions as if it were an unconditioned stimulus.

Higher-order conditioning shows that classical conditioning does not depend on the presence of a genuine, natural UCS.An already established CS can do just fine.

In higherorder conditioning, new conditioned responses are built on the foundation of already established conditioned responses.

书上举例一些Higher-Order Conditioning的例子，比如用已经建立起来的条件刺激“the tone”直接配对其它的刺激，如红灯，之后红灯也能成为狗分泌唾液的条件刺激。还有开车的司机一看见警车就焦虑的例子。