What is learning ?

A relatively permanent change in behavior brought about by experience. It is a process that must be assessed indirectly-- we can only assume that learning has occurred by observing performance, which is susceptible to such factors as fatigue and lack of effort.

How do we learn to form associations between stimuli and responses?

One major form of learning is known as classical conditioning. Studied by Ivan Pavlov, classical conditioning occurs when a neutral stimulus--one that brings about no relevant response-- is repeatedly paired with a stimulus (called an unconditioned stimulus) that brings about a natural, untrained response. For instance, a neutral stimulus may be a bell; an unconditioned stimulus may be a slice of pizza. The response pizza might bring about in a hungry person is--salivation-- is called an unconditioned response; it occurs naturally, owing to the physical makeup of the individual being trained.

The actual conditioning occurs when the neutral stimulus is repeatedly presented just before the unconditioned stimulus. After repeated pairings, the neutral stimulus begins to bring about the same response as the unconditioned stimulus. When this occurs, we can say that the neutral stimulus is now a conditioned stimulus, and the response made to it is the conditioned response. For example, after a person has learned to salivate to the sound of the bell, we say the bell is a conditioned stimulus, and the salivation is a conditioned response.

Learning is not always permanent, however. Extinction occurs when a previously learned response decreases in frequency and eventually disappears. Extinction provides the basis for systematic desensitization, a treatment designed to decrease phobia or strong irrational fear.

Stimulus generalization occurs when a conditioned response follows a stimulus that is similar to the original conditioned stimulus. The greater the similarity between the two stimuli, the greater the likelihood of stimulus generalization; the closer the new stimulus to the old one, the more similar the new response. The converse phenomenon, stimulus discrimination , occurs when an organism learns to respond to one stimulus but not to another.

Higher-order conditioning occurs when an established conditioned stimulus is paired with a neutral stimulus, and a new neutral stimulus comes to evoke the same conditioned response as the original conditioned stimulus. The neutral stimulus changes , then, into another conditioned stimulus.

What is the role of reward and punishment in learning?

A second major form of learning is operant conditioning. Moving beyond Edward Thorndike’s original work on the law of effect, which states that responses that produce satisfying results are more likely to be repeated that those that do not, B.F. Skinner carried the theory further with his precision in experimentation.

According to Skinner, the major factor underlying learning is the reinforcer-- any stimulus that increases the probability that the preceding response will occur again. We can determine whether a stimulus is a reinforcer only by observing its effects upon behavior. If behavior increases, the stimulus is by definition a reinforcer. Primary reinforcers involves rewards that are naturally effective without prior exposures because they satisfy a biological need. Secondary reinforcers, in contrast, begin to act as if they were primary reinforcers through frequent pairings with a primary reinforcer.

Positive reinforcers are stimuli that are added to the environment and lead to an increase in a preceding response. Negative reinforcers are stimuli whose removal from the environment leads to an increase in the preceding response. Negative reinforcement occurs in two major forms. In escape conditioning, an organism learns to make an response that brings about an end to an aversive situation. In avoidance conditioning, an organism responds to a signal of an impending unpleasant event in a way that permits its evasion.

Punishment is the administration of an unpleasant stimulus following a response in order to produce a decrease in the incidence of that response. Punishment can also be characterized by the removal of a positive reinforcer. In contrast to reinforcement, in which the goal is to increase the incidence of behavior, punishment is meant to decrease or suppress behavior. Although there is some benefits to the use of punishment, its disadvantages usually outweigh its positive effects.

Schedules and patterns of reinforcement affect the strength and duration of learning. Generally, partial reinforcement schedules--in which reinforcers are not delivered on every trial--produce stronger and longer lasting learning than continuous schedules. Among the major categories of reinforcement schedules are fixed and variable ratio schedules, which are based on the number of responses made, and fixed and variable interval schedules, which are based on the time interval that elapses before reinforcement is provide. Fixed ratio schedules provide reinforcement only after a certain number of responses are made; variable-ratio schedules provide reinforcement after a varying number of responses are made-- although the specific number of typically settles around some average. In contrast, fixed-interval schedules provide reinforcement after a fixed amount of time; variable-interval schedules provide reinforcement over varying amounts of time, although the times form a specific average.

Superstitious behavior results from the mistaken belief that particular ideas, objects or behavior will cause certain events to occur. It occurs as a consequence of learning that is based on the coincidental association between a stimulus and subsequent reinforcement.

Shaping is a process for teaching complex behaviors by rewarding closer and closer approximations of the desired final behavior. Shaping forms the basis for learning many everyday skills and is central to presenting complicated information in textbooks and in computerized programmed instruction.

What is the role of cognition and thought in learning?

Cognitive approaches consider learning in terms of thought processes or cognition. Phenomena such as latent learning-- in which a new behavior is learned but not performed until reinforcement is provided for its performance-- and the apparent development of cognitive maps support cognitive approaches.

Learning also occurs through observation of behavior of others, known as models. The major factor that determines whether an observed behavior will actually be performed is the nature of reinforcement or punishment a model receives. Learned helplessness, the learned belief of a person or animal that it cannot exert control over the environment, also suggests the importance of cognitive processes in learning.

What is memory?

Memory is the process by which we encode, store, and retrieve information. There are three basic kinds of memory storage: sensory memory, short-term memory, and long term memory

Are there different kinds of memory?

Sensory memory ( made up of memories corresponding to each of the sensory systems) is the first place where information about the world is saved, although the memories are very brief. For instance, iconic memory (made up of visual sensations) lasts less that a second, and echoic memory (corresponding to auditory sensations) lasts less that four seconds. Despite their brevity, sensory memories are very precise, storing almost an exact replica of each stimulus to which a person is exposed. Unless they are transferred to other types of memory, however, sensory memories appear to be lost.

Roughly seven (plus or minus two) chunks of information are capable of being transferred and held in short term memory. A chunk is a meaningful bit of information, ranging in size from a letter or a single digit to a more complicated categorizations. Information in short-term memory is held from fifteen to twenty five seconds and, if not transferred to long term memory, is lost primarily through interference, as well as through decay. Interference is the loss of material through the displacement of older material by newer information, whereas decay is the loss of information through its non-use.

Memories are transferred into long-term storage through rehearsal. The most effective type is elaborative rehearsal, in which the material to be remembered is organized and expanded. Formal techniques for organizing material are called mnemonics.

If memories are transferred into long term memory, they become relatively permanent. Long term memories are of two types: episodic and semantic. Episodic memories relate to our individual lives (such as recalling what your childhood playmate looked like); semantic memories consists of organized knowledge and facts about the world (for example, 3 x 2 =6 ).

The levels-of processing approach to memory suggests that the way in which information is initially perceived and analyzed determines the success with which the information is recalled. The deeper the initial processing, the greater the recall of the material.