Theories and facts of evolutionary psychology with special reference to reasoning and sex difference studies.

1)进化心理学的理论介绍：我们写了几篇关于进化心理学最新趋势的评论文章。2）推理研究：采用Wason选择任务进行推理实验，探讨合作群体中搭便车行为的检测机制。130名六年级学生和本科生在分享问题上检查是否存在搭便车现象。3）认知性别差异研究：我们撰写了几篇将性别选择理论与认知性别差异联系起来的理论论文。4）杀人研究：根据进化理论对日本近40年的杀人数据进行分析，发现日本年轻男性的杀人率急剧下降，但杀人率却异常高。

1) Introducing of the theories of evolutionary psychology : We wrote several review articles about recent trends in evolutionary psychology. We also organized to open a mailing list in internet and to hold monthly regular meeting about human behavior and evolution.2) Reasoning studies : We conducted several reasoning experiments using Wason Selection Task in order to investigate free-rider detection mechanism in cooperative group. 130th six grade pupils and undergraduates checked the existence of free-rider on sharing the problem.3) Cognitive sex difference studies : We wrote several theoretical paper which link sexual selection theory and cognitive sex differences. Empirical researches and experiments were conducted on sexual jealousy, emotional love, mental rotation and special memory.4) Homicide studies : We analyzed Japanese homicide data of last 40 years based on evolutionary theories and found drastic decrease in homicide rate among young males as well as the exceptional high rate of infanticide in Japan.