Abstract: From the perspective of evolutionary psychology, sex preference is adaptive. Humans adjust sex ratio and sex investment to maximize themselves' reproduction. Our study focused on the effects of sex preference with different sex reproductive advantage. Study 1, we manipulated the levels of male reproductive advantage by cuing participants that they had different amount of resource(money) and found that: participants preferred male offspring to female offspring when male reproductive advantage was high, yet preferred female offspring more than male offspring when male reproductive advantage was low. Study 2, we manipulated the levels of female reproductive advantage by cuing participants that the current sexual relationships were stable or unstable and the paternity uncertainty were low or high and found that: the degree of girls preference (the fixation time that participants gazed at girls minus that at boys) was stronger when the female reproductive advantage was high than the female reproductive advantage was low. These studies suggested which sex of offspring that parents prefer to are uncertain, it dues to which sex of offspring has more fittest.

Key words: sex preference, reproduction advantage, paternity uncertainty, Trivers-Willard hypothesis

摘要： 采用眼动技术探究性别繁衍优势对性别偏爱的影响。实验一通过实验材料启动男性繁衍优势的高低，记录被试在不同启动条件下对男孩图片和女孩图片的注视时间，结果发现：当男性繁衍优势高时，被试注视男孩图片时间显著高于女孩图片，表现为男孩偏爱；而当男性繁衍优势低时则相反，表现为女孩偏爱；实验二通过实验材料启动女性繁衍优势的高低，记录被试在不同启动条件下对男孩图片和女孩图片的注视时间，结果发现两种启动条件下被试对女孩图片的注视时间均高于男孩图片，表现为女孩偏爱；然而，与女性繁衍优势低时相比，当女性繁衍优势高时，对女孩的偏爱程度更高。研究结果表明亲代对子代的性别偏爱可能是基于提高亲代自身繁衍效率的考虑，具有进化意义。

关键词: 性别偏爱, 繁衍优势, 父亲身份不确定性, Trivers-Willard假设