Resumen de Evidências empíricas da lei do menor esforço: considerações sobre o custo da resposta

Tiago de Oliveira Magalhães, Luan Mendes Teixeira

• English

  According to the principle of least effort, organisms tend to behavior in order to avoid unnecessary expenditure of energy or resources. This principle was tested through differents experimental designs, with distincts concepts of effort. It is usually operationalized consider the effort as the amount of responses required to obtain reinforcement, what makes the notion of effort closer to the concept of ratio schedule of reinforcement. Effort can be also defined as the minimum force required during the emission of each response, concept that is often found in its experimental literature. In both possibilities, most experts defend that the principle of least effort, inherently to operant behavior, is an accurate description of broad functional relations. The purpose of this essay is to revisit researches that investigate the effects of effort on response rate and discuss whether its findin-gs support the principle of least effort or not. The results of this research show that the suppressive effects of increasing effort are not unanimously accepted by behavioral scientists. Some experimental data imply that there are circumstances and methodological arrangements in which increasing the physical demand of the operandum can lead to an increase of the response rate. Concomitantly, there are data on choice designs showing a consistent preference for the highest effort option. Something similar is observed in the phenomenon known as contrafreeloading, in which the subjects emit operant responses for the production of food, even when food is freely available. These studies are relevant because they broaden the set of experimental phenomena pertinent to the discussion of the principle of least effort and raise important methodological issues. These contributions, however, are not enough to state that the principle of least effort is invalid or outdated. Phenomena like contrafreeloading can be interpreted in a way that they are not in conflict with the principle of least effort. In addition, methodological limitations of some experiments that support this principle do not necessarily refute the principle itself. The studies whose results supposedly contradict the principle of least effort themselves have important methodological limitations, what shows that this topic demands a considerable amount of empirical research.

• português

  O princípio do menor esforço pode ser compreendido como uma sumarização de observações que apontam para uma maior probabilidade dos organismos se comportarem despendendo o menor esforço possível. Essas observações usualmente comparam as taxas de resposta sob diferentes condições de esforço que podem variar entre fases do experimento ou apresentadas simultaneamente em esquemas de reforço concorrentes. O objetivo deste ensaio é revisar pesquisas que investigam os efeitos do esforço sobre a taxa de resposta e discutir se seus achados permitem endossar ou refutar o princípio do menor esforço. Algumas pesquisas parecem indicar que os efeitos supressivos do esforço não são universais e que existem circunstâncias e arranjos metodológicos que, mediante o aumento na exigência física, ocasionam aumento na taxa de respostas. Concomitantemente, há dados em delineamentos de escolha que mostram uma preferência consistente pela opção de maior esforço. Entretanto, o conjunto desses achados, apesar de oferecer uma maior diversificação no estudo dos efeitos do esforço sobre o comportamento, não permite refutar definitivamente o princípio do menor esforço. As pesquisas que aparentemente contrariam o princípio do menor esforço apresentam problemas conceituais e metodológicos que precisam ser superados para que suas hipóteses sejam devidamente submetidas à testagem experimental.