中文摘要：

在以往禀赋效应研究的基础上，本研究引入中立方估价值作为参照，在时间维度上探讨了禀赋效应的变化趋势，并尝试延伸禀赋效应的定义。研究发现，随着卖方拥有物品的时间延长，买卖双方的估价呈下降趋势，卖方的估价总是显著高于买方，但买卖双方的估价之差不随卖方拥有物品的时间延长发生变化；以中立方的估价为参照，在较短的时间内卖方的估价倾向于理性，在较长的时间内买方的估价倾向于理性；卖方的估价在时间水平上相对于中立价格呈递增性，而买方的估价相对于中立价格呈递减性。引人中立方再探讨禀赋效应并没有否定它的存在，而且能够更好地解释生活中的非理性行为。

英文摘要：

In behavioral economics, the endowment effect refers to the phenomenon that people usually demand higher prices to relinquish an object they own than they would be willing to pay to acquire the object they did not own （Kahneman, Knetsch, ＆ Thaler, 1990）. For this phenomenon, dozens of studies have found the significant disparity between willingness to pay （WTA） and willingness to accept compensation （WTA）, and this disparity is believed as an important reason to account for this effect. However, the WTA-WTP disparity cannot adequately interpret the endowment effect because sellers or buyers may be irrational traders. Therefore it is necessary to compare the endowment effect with the rational behavior. For this reason, in the present study we introduced the neutrals whose evaluation was regarded as reference price for reinterpreting endowment effect. In addition, one notable weakness of the previous researches in this domain is that the time period of the ownership is ignored. Although endowment effect can come from an instant valuation, the ownership in real life is dynamic and it may change with the time. Thereby, it is necessary to weigh the endowment effect on a dynamic time of change. Considering that, we inspected the changes of the WTA-WTP disparity in two continuous time periods including ＂past-present＂ and ＂present-future＂. In this study, we posited that valuation of sellers or buyers was decreased both in the ＂past-present＂ and ＂present-future＂ time periods, whereas WTA-WTP disparity was unchanged. When the valuation of neutrals as reference price （market price, MP） was introduced, WTA-WTP disparity would be divided into two parts： WTA-MP and MP-WTP. We inferred that MP would decline into a range between WTA and WTP, and the variation tendency of WTA-MP would be different from MP-WTP in a given time period. A total of 674 undergraduates and 35 computer sellers participated in three experiments. In Experiment 1, the participants were randomly assigned to each of 12 sc