Creativity Stage Theory


CRESPI EFFECT. The American psychologist Leo P. Crespi (1916- ) is credited with the finding that in learning experiments on lower animals there is a disproportionate in-crease in a response with an increase in incentive. For example, if an animal presses a lever for one gram of food reinforcement and then is shifted suddenly to five grams of reinforcement, it will respond characteristically at a higher rate than a comparable animal that has been receiving five-gram reinforcements all along. This sudden shift in "attractiveness" of a reward is called the Crespi effect or the contrast effect [cf., contrafreeloading effect - paradoxical behavior where organisms work for reinforcement even though the identical reinforcement is available freely, as when a rat presses a lever repeatedly for food ("earned reinforcer") that is available simply to be taken with less effort from a nearby dish ("free reinforcer")]. Another example of the Crespi effect is seen in rats learning to run a maze: if a large amount of food provides the incentive, the rats run to the goal faster than if the amount of food is small. Thus, with practice, the rats in these two conditions (large reward versus small reward) show a significant difference in running speeds. Subsequently, once the levels of running are established in each condition, switching the amounts of food for the two groups has an immediate effect on maze-running performance. Rats that had received a large reward and now receive a small reward run more slowly. On the other hand, rats that had received a small reward and now receive a large reward run faster (cf., compliance effects and techniques). Additionally, the rats' performance with the changed reward often "overshoots" the mark expected from their earlier behavior. The rats switched from a large reward to a small one run more slowly than predicted, whereas those rats switched from a small reward to a large one run faster than expected. Increased performance as a result of going from small to a large reward is termed positive contrast, or an elation effect, whereas the poorer performance associated with going from a large to a small amount of reward is termed negative contrast, or a depression effect (cf., nonre-ward hypothesis - posits that an organism that expects a reward upon performing in a conditioning paradigm, but does not receive the reward, is frustrated and leads to greater efforts following subsequent stimuli). The replicability of Crespi's findings has been controversial. Although many studies support the Crespi effect and Crespi's earlier findings, a number of other researchers have not been able to obtain such effects. K. Spence (1956) failed to find positive contrast effects and suggested that the positive contrast effect obtained by Crespi was a function of the original high-reward group participants' not having reached their asymptote and that the shift-group responded to at the higher level because of the additional training trials. Spence does report, however, finding negative contrast effects. Thus, although the negative contrast effect seems to stand as a viable concept in the field, there have been questions about the validity of the positive contrast effect. Optimal explanations for the contrast effects may depend, ultimately, on whether only negative contrast effects are thought to be obtainable, or whether both positive and negative contrast effects may be considered as bona fide phenomena. If it is assumed that both types are obtainable, then a theory such as H. Helson's adaptation-level theory - as applied to conditioning and reinforcement - may be a feasible option. See also COMPLIANCE EFFECTS AND TECHNIQUES; HELSON'S ADAPTATIONLEVEL THEORY; LEARNING THEORIES/LAWS. REFERENCES

Crespi, L. (1942). Quantitative variation of incentive and performance in the white rat. American Journal of Psychology, 55, 467-517. Crespi, L. (1944). Amount of reinforcement and level of performance. Psy-chologicalReview, 51, 341-357. Spence, K. (1956). Behavior theory and conditioning. New Haven, CT: Yale University Press. Helson, H. (1964). Adaptation-level theory: An experimental and systematic approach to behavior. New York: Harper & Row.

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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