Generalization Principles Of

The principle of response generalization states that an increase (or decrease) in the strength of one response through a reinforcement (or extinction) procedure is accompanied by a similar, but smaller, increase (or decrease) in the strength of other responses that have properties common with the first response. The principle of stimulus generalization is the tendency for stimuli similar to the original stimulus in a learning situation to produce the response originally acquired (cf., the unit hypothesis - the amount of generalization along a continuum decreases with the number of test stimuli that lie between the training stimulus and a given test stimulus and increases with the number that lie beyond it). Although there has been a tendency to regard stimulus generalization as a "fundamental" process, it has been noted that when it occurs, it may be viewed simply as the failure of the organism to have established a "discrimination" (i.e., the ability to perceive and respond differentially to differences between two or more stimuli) between the original stimulus and the new one(s). Stimulus generalization was first demonstrated by Ivan Pavlov in 1927 in laboratory experiments with dogs: after the dog experiences a succession of pairings between a stimulus such as a tone (e.g., 200 Hz) and food reinforcement, a stimulus similar in character (e.g., 400 Hz) and yet discriminably different from the original tone is presented without reinforcement. This procedure results in the establishment of the excitatory gradient of generalization, which shows that the intensity of the animal's response to the test stimulus is directly proportional to its similarity to the training stimulus (cf., octave effect - refers to the result that occurs when an organism is conditioned to respond to a tone, and the response generalizes more to a pitch that is an octave higher, or lower, than to one that is actually closer to the original tone). Pavlov placed great importance on stimulus generalization and saw it as biologically adaptive: animals generalize their responses to stimuli other than the original one to compensate for the instability of the environment. The early emphasis on the adaptive value of stimulus generalization led later theorists (e.g., K. W. Spence; C. L. Hull) to treat it as a fundamental and irreducible aspect of learning. The later theorists derived other, more complex psychological phenomena from the concept of gener alization. The theories of generalization began with Pavlov's physiological theory, in which he argued that generalization from the training (original) stimulus to the testing (similar) stimuli was due to a spreading wave of excitation across the cortex. Pavlov's theory may be dismissed, however, with the observation that there is no physiological evidence for cortical waves then or now. Later, Hull wrote about generalization in terms of the spread of habit strength in a way similar to Pavlov's spread of cortical excitation. The common aspect to both Pavlov's theory and Hull's theory concerning generalization is that it was seen as an innate propensity of the brain that was hypothesized to occur naturally via cortical waves or habit structures once a training stimulus came to elicit a response reliably. The theoretical development of generalization lay dormant for a number of years until the appearance of the Lashley-Wade hypothesis -named after the American neuropsychologist Karl Spencer Lashley (1890-1958) and the American psychologist Marjorie Wade (1911) - which suggested that the view of innate generalization is incorrect. Rather, generalization occurs because of failure to discriminate the training stimulus from the test stimulus. According to Lashley and Wade, the dimensions of a stimulus series are determined by comparison of two or more stimuli and do not exist for the organism until established by differential training. Thus, the Lashley-Wade hypothesis asserts that there is no generalization (or generalization gradient) without discrimination learning, and the organisms learns about the dimensions of stimuli by training to discriminate differences between them. There is both a strong and a weak interpretation of the Lashley-Wade hypothesis. The strong interpretation is that all generalization is a function of discrimination experience with no contribution from innate sources. The weak interpretation is that there may be influences from innate sources but, nevertheless, training in discriminating the values of a stimulus dimension will affect generalization. Conclusions from research concerning the strong interpretation have been negative, whereas studies focusing on the weak interpretation have shown positive evidence. In addition to discrimination training, other variables such as schedules of reinforcement and amount of training are important for amount of generalization. Generalization can be excitatory (in which the spread of responding occurs with respect to the training stimulus that has been reinforced), or it can be inhibitory (in which there is a spread of non-responding with respect to the stimulus that has not been reinforced). Recently, a cognitively oriented explanation of stimulus generalization rivals the earlier interpretations. In this approach, stimulus generalization is regarded as a special case of stimulus classification: the organism categorizes discriminably different events as equivalent and responds to them in terms of their class membership rather than to their peculiarities. In another area of research, the behavioral contrast effect/phenomenon -where a behavioral change occurs as a consequence of a transition from one condition of reinforcement to another - has attracted the interest of psychologists because it appears to be an exception to the laws of extinction and stimulus generalization. The issue as to whether behavioral contrast can be incorporated into existing laws of conditioning, or whether new laws must be formulated to account for the phenomenon, is still unresolved. Apparently, although psychologists are closer now than they once were to a comprehensive explanation of generalization, they are still lacking a fundamental theory. See also AM-SEL'S HYPOTHESIS/THEORY; ASSOCIATIVE SHIFTING, LAW OF; CAPALDI'S THEORY; DISCRIMINATION/GENERALIZATION HYPOTHESIS; DISCRIMINATION LEARNING THEORY; HULL'S LEARNING THEORY; INTERFERENCE, THEORIES OF; LASHLEY'S THEORY; PAVLOVIAN CONDITIONING PRINCIPLES/LAWS/THEORIES; SPENCE'S THEORY.

Conquering Fear In The 21th Century

Conquering Fear In The 21th Century

The Ultimate Guide To Overcoming Fear And Getting Breakthroughs. Fear is without doubt among the strongest and most influential emotional responses we have, and it may act as both a protective and destructive force depending upon the situation.

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