A questão da metodologia de Finanças Comportamentais

Um dos problemas interessantes de FC é a questão metodológica. Boa parte dos artigos desenvolvidos neste campo tem sua origem em situações experimentais. Geralmente um questionário com uma situação problema é aplicado e solicita-se ao respondente que escolha uma alternativa. Este tipo de metodologia tem recebido críticas - apesar de ter sido coroado recentemente com um Nobel em economia - por não expressar a realidade. Como testar o comportamento dos indivíduos diante de situações reais?

O texto a seguir reconhece os limites dos experimentos em laboratórios e afirma que as evidências sugerem que as anomalias de comportamento são menos pronunciadas na prática do que previamente observada em laboratório.

"Homo Economicus Evolves"

Steven D. Levitt and John A. List on behavioral economics. This is from Science:

Homo economicus Evolves Steven D. Levitt and John A. List, Science 15 February 2008: Vol. 319. no. 5865, pp. 909 - 910 DOI: 10.1126/science.1153640: ...The discipline of economics is built on the shoulders of the mythical species Homo economicus. Unlike his uncle, Homo sapiens, H. economicus is unswervingly rational, completely selfish, and can effortlessly solve even the most difficult optimization problems. This rational paradigm has served economics well, providing a coherent framework for modeling human behavior. However, a small but vocal movement in economics has sought to dethrone H. economicus, replacing him with someone who acts "more human." This insurgent branch, commonly referred to as behavioral economics, argues that actual human behavior deviates from the rational model in predictable ways. Incorporating these features into economic models, proponents argue, should improve our ability to explain observed behavior. ...

Perhaps the greatest challenge facing behavioral economics is demonstrating its applicability in the real world. In nearly every instance, the strongest empirical evidence in favor of behavioral anomalies emerges from the lab. Yet, there are many reasons to suspect that these laboratory findings might fail to generalize to real markets. We have recently discussed [11] several factors, ranging from the properties of the situation--such as the nature and extent of scrutiny--to individual expectations and the type of actor involved. For example, the competitive nature of markets encourages individualistic behavior and selects for participants with those tendencies. Compared to lab behavior, therefore, the combination of market forces and experience might lessen the importance of these qualities in everyday markets.

Recognizing the limits of laboratory experiments, researchers have turned to "field experiments" to test behavioral models [12]. Field experiments ... avoid many of the important obstacles to generalizability faced by lab experiments.

Some evidence thus far suggests that behavioral anomalies are less pronounced than was previously observed in the lab [13] . For example, sports card dealers in a laboratory setting are driven strongly by positive reciprocity, i.e., the seller provides a higher quality of good than is necessary, especially when the buyer offers to pay a generous price. This is true even though the buyer has no recourse when the seller delivers low quality in the lab experiment. Yet, this same set of sports card traders in a natural field experiment behaves far more selfishly. They provide far lower quality on average when faced with the same buyer offers and increase quality little in response to a generous offer from the buyer. ...

Stigler (16) wrote that economic theories should be judged by three criteria: generality, congruence with reality, and tractability. We view the most recent surge in behavioral economics as adding fruitful insights--it makes sense to pay attention to good psychology. At the very least, psychological insights induce new ways to conceptualize problems and provide interesting avenues of research. In their finest form, such insights provide a deeper means to describe and even shape behaviors. One important practical example involves savings decisions, where it has been shown that decision-makers have a strong tendency to adhere to whatever plan is presented to them as the default option, regardless of its characteristics. ... The changes in behavior induced by changing default rules dwarf more "rational" approaches to influence choice such as information provision or financial education.

Behavioral economics stands today at a crossroads. On the modeling side, researchers should integrate the existing behavioral models and empirical results into a unified theory rather than a collection of interesting insights, allowing the enterprise to fulfill its enormous potential. To be empirically relevant, the anomalies that arise so frequently and powerfully in the laboratory must also manifest themselves in naturally occurring settings of interest. Further exploring how markets and market experience influence behavior represents an important line of future inquiry. ...

Grifo meu.