Behavioral contrast

<h2 id="history-of-contrast-effects">History of contrast effects</h2>
In 1942, Crespi measured the speed of <a href="/facts/Rat/5rn6uEKM">rats</a> running to various amounts of reward at the end of an alley. He found that the greater the magnitude of reward, the faster the rat would run to get the reward.<a class="footnote-ref" id="fnref:3" href="#fn:3">3</a> In the middle of his experiment Crespi shifted some of his animals from a large reward to a small reward. These animals now ran even more slowly than control animals that had been trained on small reward throughout the experiment. This <a href="/facts/Overshoot_(signal)/l450BHuI">overshoot</a> is an example of successive negative contrast. Likewise, other animals shifted from small to large reward ran faster than those trained on the larger reward throughout (successive positive contrast). Crespi originally called these effects depression and elation respectively, but, in 1949, Zeaman suggested changing the names to negative contrast and positive contrast.<a class="footnote-ref" id="fnref:4" href="#fn:4">4</a> The combined concept of behavioral contrast is sometimes also referred to as the <a href="/facts/Crespi_effect/jdwRUuVw">Crespi effect</a>. 
In 1981, Bower discovered that positive contrast may be reduced because the response measure hits a ceiling. Thus, if contrast is the subject of an experiment, reward sizes may need to be adjusted to keep the response below such a ceiling.<a class="footnote-ref" id="fnref:5" href="#fn:5">5</a> In 1996, Flaherty suggested that negative contrast was related to frustration; that is, the sudden shift to a low reward causes frustration for the person or the animal, and this frustration interferes with the behavior the subject is performing.<a class="footnote-ref" id="fnref:6" href="#fn:6">6</a>

<h2 id="references">References</h2>

<ol>
<li id="fn:1">Mackintosh, N. J. (1974) The Psychology of Animal Learning. New York: Academic Press <a href="#fnref:1" class="footnote-back-ref">↩</a></li>
<li id="fn:2">Catania, A. C.(1992) Learning. Englewood Cliffs NJ: Prentice-Hall <a href="#fnref:2" class="footnote-back-ref">↩</a></li>
<li id="fn:3">Crespi, Leo P. (1942). Quantitative variation of incentive and performance in the white rat. American Journal of Psychology, 55, 467-517 <a href="#fnref:3" class="footnote-back-ref">↩</a></li>
<li id="fn:4">Zeaman, D. (1949). Response latency as a function of the amount of reinforcement. Journal of Experimental Psychology, 39, 466-483 <a href="#fnref:4" class="footnote-back-ref">↩</a></li>
<li id="fn:5">Bower, G. H., & Hilgard, E.R. (1980). Theories of Learning (5th ed.) Englewood Cliffs, NJ: Prentice-Hall <a href="#fnref:5" class="footnote-back-ref">↩</a></li>
<li id="fn:6">Flaherty, C.F. Incentive Relativity New York, NY: Cambridge University Press <a href="#fnref:6" class="footnote-back-ref">↩</a></li>
</ol>

Behavioral contrast open-in-new

Behavioral contrast