Generalized Expected Utility, Heteroscedastic Error, and Path Dependence in Risky Choice

We evaluate the fit of several generalized expected utility models under homoscedasticity and three different heteroscedastic error structures for the data set first reported in Hey and Orme (1994). Standard chi-squared tests are used for nested tests, and both the Akaike (1973) information criterion and its consistent version (Hurvich and Tsai, 1989) are used for non-nested ranking of these models. A testing framework is developed that explicitly accounts for the path-dependent nature of the model selection problem. Not only does the selection of preference models depend on the error structure assumed, but the reverse is also true: the selection of the error structure depends on the preference structure assumed. An erratum to this article is available at .     

Testing the Effects of Similarity on Risky Choice: Implications for Violations of Expected Utility

Our aim in this paper was to establish an empirical evaluation for similarity effects modeled by Rubinstein; Azipurua et al.; Leland; and Sileo. These tests are conducted through a sensitivity analysis of two well-known examples of expected utility (EU) independence violations. We found that subjective similarity reported by respondents was explained very well by objective measures suggested in the similarity literature. The empirical results of this analysis also show that: (1) the likelihood of selection for the riskier choice increases as the pair becomes more similar, (2) these choice patterns are consistent with well-known independence violations of expected utility, and (3) a significant proportion of individuals exhibit intransitive choice patterns predicted under similarity effects, but not allowed under generalized expected utility models for risky choice.     

Brief Communications: Gender Differences in Gambling Progression

The authors compared 39 women and 38 men entering an outpatient treatment program for pathological gambling. They were diagnosed according to DSM-IV and selected by SOGS, followed by a semi-structured interview for demography and progression of the gambling behavior prior to treatment. Women were more often single (59% vs. 26%; p = .005) and started gambling significantly later than men (34.2 vs. 20.4 years; p < .001). The progression of the disorder was more than 2 times faster in women than in men. There was no difference in the age of seeking treatment (44.7 vs. 42.3 years). Findings from this study resemble gender differences in other addictions—in particular the faster progression among women—challenge pharmacodynamic hypotheses for this phenomenon, and suggest gender into account when devising treatment strategies for pathological gambling.     

Evaluation of a Physical Activity Program for Pathological Gamblers in Treatment

It has been demonstrated that craving for gambling is associated with anxiety and depression in pathological gamblers. Exercise has been shown to reduce anxiety and depression, as well as positively influence abstinence rates in individuals with substance use disorders. In this study, we examined the impact of a physical activity program in 33 pathological gamblers. We also analyzed the association between craving and plasmatic levels of stress hormones (adrenocorticotropic hormone, cortisol, and prolactin). The program involved eight 50-min sessions. Craving was assessed 24 h before, immediately before, and immediately after each session, as well as on a weekly basis. Before and after the program, we evaluated gambling behavior, depressive symptoms, anxiety, and plasma levels of stress hormones. We identified a significant reduction in craving following each session and at the end of the program. There was improvement in anxiety, depressive symptoms, and gambling behavior. The post-session reduction in craving was accompanied by post-program reductions in craving and anxiety but not by a post-program reduction in depressive symptoms. The craving reduction was associated with a variation in prolactin levels but not with variations in levels of cortisol or adrenocorticotropic hormone.     

Performance of the similarity hypothesis relative to existing models of risky choice

Experimental studies have discovered behavior that is inconsistent with the expected utility model (EU) of risky choice (von Neumann and Morgenstern, 1953). The two approaches to address these paradoxes are tested: generalized expected utility models (GEU) and models incorporating decision-making limits or costs through question similarity. Tests are carried out over risky pairs related to well-known examples from Kahneman and Tversky's (1979) influential work. Statistical analysis reveals that GEU models of choice are significantly violated for choice patterns consistent with the similarity hypothesis. Additional tests point to shortcomings in the similarity approach that are consistent with fanning out behavior.     

农业经济研究的价值

经济学家对自然科学与农业研究的价值已经进行了深入的探讨,但农业领域经济学研究的作用却鲜为人知。经济研究所提供的“产品”可分为三类:新的经济信息、促进技术进步的产品、导致政策产生的产品。每种产品的用户、影响力和效益不尽相同。我们认为,研究的作用取决于研究成果的