Facilitation of concept learning by a “simultaneous contrast” procedure

Wells, Herbert

doi:10.3758/bf03327913

Cited by 5 publications

(3 citation statements)

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“…This pattern suggests that under ordinary, nonavailability conditions, S's adopt a positive focusing strategy, basing hypotheses and inferences primarily on remembered examples of the concept. When instances of both types are retained for S, a different and possibly more efficient strategy involving simultaneous contrasts of examples and nonexamples (Wells, 1967) is workable, reducing the relative usefulness of positive instances. There actually appears to be a slight advantage to a higher proportion of negative instances, which is the more homogeneous category under both rules.…”

Section: Discussionmentioning

confidence: 99%

Concept learning as a function of the conceptual rule and the availability of positive and negative instances.

Bourne¹,

Ekstrand²,

Montgomery³

1969

Journal of Experimental Psychology

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One hundred and sixty Ss, assigned randomly to cells of a 4 (conceptual rule: conjunctive, disjunctive, conditional, and biconditional) X 4 (memory condition: feedback retained for all instances, for positive instances only, for negative instances only, for none of the instances) factorial design, solved an attribute identification problem via the selection paradigm. Rules differed in difficulty and the display of feedback for previously selected instances facilitated performance. The relative effectiveness of retained instances differed, however, with the rule; e.g., positives were more informative in conjunctive and negatives in conditional concepts. There were differences in the stimulus selection patterns of better and poorer 5"s, which also interacted with rule and memory condition.

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Section: Discussionmentioning

confidence: 99%

Concept learning as a function of the conceptual rule and the availability of positive and negative instances.

Bourne¹,

Ekstrand²,

Montgomery³

1969

Journal of Experimental Psychology

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“…EXPERIMENT 1 A two-stimulus, simultaneous discrimination procedure has been used in most investigations of frequency effects and tests of the frequency theory interpretation of verbal discrimination learning. With a few significant exceptions (e.g., Levine, 1967;Wells, 1967), this procedure is not characteristic of research on concept learning. The first experiment was executed to determine whether rule effects typically observed in concept problems could be produced with the simultaneous discrimination paradigm.…”

Section: Frequency Differentialsmentioning

confidence: 99%

Frequency analysis of attribute identification.

Bourne¹,

Ekstrand²,

Lovallo³

et al. 1976

Journal of Experimental Psychology: General

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The frequency with which values on any stimulus dimension occur within the positive (and/or negative) category of a concept is a potential cue to which dimensions are relevant. One might theorize that the development of frequency differentials among stimulus values over a series of encounters with positive and negative instances is the way people identify relevant attributes of a concept. Suggestive evidence on the importance of frequency in this process comes from our observation, made in an already published experiment (Bourne & Guy, 1968), that a series of instances which affords no large differentials is almost impossible to solve. Seven experiments, using a two-stimulus (one positive and one negative) simultaneous presentation paradigm, designed to explore frequency effects systematically are reported in this article. In the first, we show that the order of difficulty of four conceptual rules-conjunctive, disjunctive, conditional, and biconditional-in the attribute identification task is correlated with the magnitude of the frequency differentials these rules generate in a stimulus sequence. In two subsequent studies, we show that a difficult rule, the biconditional, can be made more or less difficult (indeed, quite simple) by artificially manipulating value frequencies. The frequency cue of greatest importance exists when a relevant value, a, appears more often than do all irrelevant values, a, on the same dimension within the positive category of instances. The importance of a > a is not affected by reinstating either the positive or the negative stimulus at the time of feedback, suggesting that the subject codes both stimuli at their initial presentation in each trial and augments the frequencies of values appropriately once the positive stimulus is identified by feedback. The remaining studies indicate certain qualifications on these conclusions. First, the reintroduction of an instance (positive or negative) at feedback probably adds partial increments to frequency counts serving to augment their effectiveness as cues to the relevant values. Second, differentials within the negative category can be and are used as cues to problem solution when no other cues are available. The effects observed in these studies are fully in accord with an extension of the frequency theory of discrimination learning (Ekstrand, Wallace, & Underwood, 1966). This extension accounts for a number of other results in the literature, such as the effects of intradimensional variability on attribute identification, and leads to certain expectations about stimulus sequence effects and the abstraction of prototypes representative of natural categories.

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“…Moreover, even the findings of the many studies designed to clarify the conditions most favorable for the attainment of concepts do not support unequivocally one or another cluster of theories. Some of the more important conditions are reducing the number of irrelevant attributes (e.g., Bulgarella and Archer, 1962;Keele and Archer, 1967;Kepros and Bourne, 1966); increasing the saliency of the relevant attributes (Archer, 1962;Trabasso, 1963); presenting a great number of examples of the concept, in close contiguity, (Bourne et al, 1965), most of the examples being positive instances incorporating all the relevant attributes (Haygood and Devine, 1967;Hovland and Weiss, 1953), some being negative instances which help to define the boundaries of the concept (Huttenlocher, 1962;Wells, 1967) particularly when the concept is based on a disjunctive, conditional or another principle more complex than the conjunctive (Bourne and Guy, 1968). …”

Section: Knowledgementioning

confidence: 99%