EQUIVALENCE CLASS: Complex behavior that consists of three
defining relations of reflexivity, symmetry, and transitivity.
Reflexivity refers to identity matching (e.g., Daddy is a specific
man, 9 is a specific numeral); symmetry refers to functional
reversibility (e.g., given a picture of a-dog, select the word dog,
and given the word dog, the picture of the dog is selected); and,
transitivity refers to the equivalence of three stimuli. 15 |
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EQUIVALENCE CLASS: A stimulus class (usually produced through
conditional discrimination in matching-to-sample) that includes all
possible emergent relations among its members. The properties of an
equivalence class are derived from the
logical relations of reflexivity, symmetry, and transitivity.
Reflexivity refers to the matching of a sample to itself, sometimes
called identity matching (AA, BB, CC, in these examples, each
letter pair represents a sample and its matching comparison
stimulus). Symmetry refers to the reversibility of a relation (if
AB, then BA). Transitivity refers to the transfer of the relation
to new combinations through shared membership (if AB and BC, then
AC). If these properties are characteristics of a matching
to-sample performance, then training AB and BC may produce AC, BA,
CA, and CB as emergent relations (reflexivity provides the three
other possible relations, AA, BB, and CC). Given AB and BC, for
example, the combination of symmetry and transitivity implies the
CA relation. The emergence of all possible stimulus relations after
only AB and BC are trained through contingencies is the criterion
for calling the three stimuli members of an equivalence class. The class can be extended by
training new stimulus relations (e.g., if CD is learned, then AD,
DA, BD, DB, and DC may be created as emergent relations). Stimuli
that are members of an equivalence
class are likely also to be functionally equivalent. It
remains to be seen whether the logical properties of these classes
are fully consistent with their behavioral ones. Cf. EQUIVALENCE
RELATION. |
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EQUIVALENCE RELATION: A term with various usages, including
functional equivalence (the relation between stimuli that have
become members of a functional class) as well as the mathematical
relations that define an equivalence class (especially the CA
relation). The terminology of equivalence
relations has often been interchanged with that of
equivalencies classes, but the class and relation terminologies
should be distinguished because functionally equivalent stimuli are
not necessarily members of an equivalence class. Cf. EQUIVALENCE
CLASS. |
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ERROR: In a simultaneous discrimination, a response
to a stimulus not correlated with reinforcement; in a successive
discrimination, a response in the presence of a stimulus correlated
with extinction. Because of its colloquial origins, the term often
assumes an evaluative as well as a descriptive function. CE
CORRECTION PROCEDURE. |
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ERRORLESS DISCRIMINATION PROCEDURE: The use of a fading procedure to establish a
discrimination, with no errors during the training. |
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ERRORLESS LEARNING: Acquiring particular discriminations by means
of instruction designed to prevent errors. Sequences of artificial
discriminative stimuli are arranged carefully and faded slowly and
systematically so that control eventually shifts to the natural
stimuli identified ultimately to evoke the response. 18 |
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ESCAPE: See negative reinforcement. |
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ESCAPE: The termination of an aversive stimulus by a
response. A reduction in the magnitude of an aversive stimulus by a
response is sometimes called partial or fractional escape. Cf. REINFORCEMENT. |
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ESCAPE: Any behavior that terminates a negative
reinforcer. |
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ESCAPE: The term escape
describes a relation between a performance and an aversive stimulus
in which the performance terminates the aversive stimulus.
Escape is to be contrasted with
avoidance, where the aversive stimulus does not occur at all as
long as the avoidance performance continues to postpone it. |
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