潜在的連想テスト(Implicit Association Test)のリスク認知への応用

早大学位記番号:新7568早稲田大

Dopamine D_1 Receptors and Nonlinear Probability Weighting in Risky Choice

Misestimating risk could lead to disadvantaged choices such as initiation of drug use (or gambling) and transition to regular drug use (or gambling). Although the normative theory in decision-making under risks assumes that people typically take the probability-weighted expectation over possible utilities, experimental studies of choices among risks suggest that outcome probabilities are transformed nonlinearly into subjective decision weights by a nonlinear weighting function that overweights low probabilities and underweights high probabilities. Recent studies have revealed the neurocognitive mechanism of decision-making under risk. However, the role of modulatory neurotransmission in this process remains unclear. Using positron emission tomography, we directly investigated whether dopamine D_1 and D_2 receptors in the brain are associated with transformation of probabilities into decision weights in healthy volunteers. The binding of striatal D_1 receptors is negatively correlated with the degree of nonlinearity of weighting function. Individuals with lower striatal D_1 receptor density showed more pronounced overestimation of low probabilities and underestimation of high probabilities. This finding should contribute to a better understanding of the molecular mechanism of risky choice, and extreme or impaired decision-making observed in drug and gambling addiction

Qualitatively Coherent Representation Makes Decision-Making Easier with Binary-Colored Multi-Attribute Tables: An Eye-Tracking Study

We aimed to identify the ways in which coloring cells affected decision-making in the context of binary-colored multi-attribute tables, using eye movement data. In our black-white attribute tables, the value of attributes was limited to two (with a certain threshold for each attribute) and each cell of the table was colored either black or white on the white background. We compared the two natural ways of systematic color assignment: “quantitatively coherent” ways and “qualitatively coherent” ways (namely, the ways in which the black-white distinction represented the quantitative amount distinction, and the ways in which the black-white distinction represented the quality distinction). The former consists of the following two types: (Type 1) “larger is black,” where the larger value-level was represented by black, and “smaller is white,” and (Type 2) “smaller is black.” The latter consisted of the following two types: (Type 3) “better is black,” and (Type 4) “worse is black.” We obtained the following two findings. [Result 1] The qualitatively coherent black-white tables (Types 3 and 4) made decision-making easier than the quantitatively coherent ones (Types 1 and 2). [Result 2] Among the two qualitatively coherent types, the “black is better” tables (Type 3) made decision making easier; in fact, the participants focused on the more important (black) cells in the case of “black is better” tables (Type 3) while they did not focus enough on the more important (white) ones in the case of the “white is better” tables (Type 4). We also examined some measures of eye movement patterns and showed that these measures supported our hypotheses. The data showed differences in the eye movement patterns between the first and second halves of each trial, which indicated the phased or combined decision strategies taken by the participants

Adverse obstetrical outcomes for women with endometriosis and adenomyosis: A large cohort of the Japan Environment and Children's Study.

BackgroundBecause of the increased number of diagnosed cases of endometriosis or adenomyosis resulting in infertility, many women require assisted reproductive technology (ART) to become pregnant. However, incidences of obstetric complications are increased for women who conceive using ART. There has been no prospective cohort study examining the influence of endometriosis and adenomyosis on obstetric outcomes after adjusting for the confounding influence of ART therapy.ObjectiveThis study evaluated the impact of endometriosis and adenomyosis on the incidence of adverse pregnancy outcomes.Study designData were obtained from a prospective cohort study, known as the Japan Environment and Children's Study (JECS), of the incidence of obstetric complications for women with endometriosis and adenomyosis. The data of 103,099 pregnancies that resulted in live birth or stillbirth or that were terminated through abortion between February 2011 and July 2014 in Japan were included.ResultsWomen with endometriosis or adenomyosis were at increased risk for complications during pregnancy compared to those without a medical history of endometriosis (odds ratio [OR], 1.32; 95% confidence interval [CI], 1.23 to 1.41) or adenomyosis (OR, 1.72; 95% CI, 1.37 to 2.16). Our analysis showed that the adjusted ORs for obstetric complications of pregnant women who conceived naturally or after infertility treatment that did not involve ART therapy were 1.26 (CI, 1.17 to 1.35) for pregnant women with a history of endometriosis and 1.52 (CI, 1.19 to 1.94) for those with a history of adenomyosis.ConclusionsThe presence of endometriosis and adenomyosis significantly increased the prevalence of obstetric complications after adjusting for the influence of ART outcomes

Honesty mediates the relationship between serotonin and reaction to unfairness

How does one deal with unfair behaviors? This subject has long been investigated by various disciplines including philosophy, psychology, economics, and biology. However, our reactions to unfairness differ from one individual to another. Experimental economics studies using the ultimatum game (UG), in which players must decide whether to accept or reject fair or unfair offers, have also shown that there are substantial individual differences in reaction to unfairness. However, little is known about psychological as well as neurobiological mechanisms of this observation. We combined a molecular imaging technique, an economics game, and a personality inventory to elucidate the neurobiological mechanism of heterogeneous reactions to unfairness. Contrary to the common belief that aggressive personalities (impulsivity or hostility) are related to the high rejection rate of unfair offers in UG, we found that individuals with apparently peaceful personalities (straightforwardness and trust) rejected more often and were engaged in personally costly forms of retaliation. Furthermore, individuals with a low level of serotonin transporters in the dorsal raphe nucleus (DRN) are honest and trustful, and thus cannot tolerate unfairness, being candid in expressing their frustrations. In other words, higher central serotonin transmission might allow us to behave adroitly and opportunistically, being good at playing games while pursuing self-interest. We provide unique neurobiological evidence to account for individual differences of reaction to unfairness