Based on the group heuristic model and the model of intuitive cooperation, we hypothesized that in-group favoritism would be conspicuously shown through an intuitive process. To test this hypothesis, we utilized a minimal group paradigm, which is traditionally used in social psychological studies, and manipulated decision time in a one-shot prisoner’s dilemma game to compare the cooperative contribution level toward in-group and out-group members under three conditions: intuitive, empathic deliberation, and rational deliberation. Our findings confirmed that in-group favoritism was clearly shown in the intuitive condition only, suggesting that the intuitive cooperation model may only be valid in the context of social exchange with in-group members. Additional analysis also showed that in-group favoritism disappeared for participants who had been forced into empathic or rational deliberation for decision making. The theoretical implications of the findings are discussed.

While the special needs education system in Japan has shifted from a segregated approach to a more inclusive one, the actual implementation of this approach may be less than ideal. The implementation of inclusive education faces several challenges, such as difficulty in meeting individual needs and lack of medical support systems in general school settings. With this in mind, we conducted a web-based survey of Japanese schoolteachers to empirically examine their attitudes and perceptions regarding inclusive education. We also sought to determine the socio-environmental and individual factors that affect the attitudes and perceptions of Japanese elementary and junior high school teachers regarding the implementation of inclusive education. Survey results showed that schoolteachers regard the idea of inclusive education as desirable, but not feasible. However, we found that schoolteachers' perceptions of the feasibility of inclusive education implementation were positively associated with their help-seeking preference if they perceived their climate as being sufficiently collegial. Based on these findings, we discuss the educational environment in which inclusive education could be successfully implemented.

The current study sought to examine the association between the level of general trust and the judgment accuracy of others’ cooperativeness. Based on data collected from 107 female first-year undergraduate students, we demonstrated that a high level of general trust was associated with a high level of judgment accuracy of group members’ cooperation in a social dilemma game. Additional analysis suggested that the association was present even when the judgment accuracy was divided into hit rate (i.e., the rate of correct judgment on the cooperator as a cooperative) and correct rejection rate (i.e., the rate of correct judgment on the non-cooperator as a non-cooperative) by controlling the participants’ judgment bias, Big Five personality traits, and the proportion of cooperators in the group. These results are in accordance with previous studies insofar as they suggest that high trusters are more skilled at discerning others’ trustworthiness. The current study adds to the evidence that high trusters have increased cognitive skills and supports Yamagishi’s emancipation theory of trust.

In the trolley problem, a well-known moral dilemma, the intuitive process is believed to increase deontological judgments, while deliberative reasoning is thought to promote utilitarian decisions. Therefore, based on the dual-process model, there seems to be an attempt to save several lives at the expense of a few others in a deliberative manner. This study examines the validity of this argument. To this end, we manipulate decision-making time in the standard trolley dilemma to compare differences among 119 Japanese female undergraduates under three conditions: intuitive judgment, deliberative judgment, and judgment after a group discussion. The current results demonstrate that utilitarian judgments decreased from 52.9% in the intuition condition to 43.7% in the deliberation condition and 37.0% after the discussion. Additional analysis suggests that the decrease in utilitarian judgments may be related to psychological unwillingness to assume responsibility for the lives of others rather than to an increase in deontological judgments. Finally, these results are discussed from an adaptationist perspective.