| One of the most important findings in the field of decision psychology is the endowment effect,which was proposed by Richard H.Thaler in 1980.The endowment effect refers to the tendency of individuals to overestimate the value of the goods they own.Once something is part of their endowment,people tend to be hard to give up and overestimate its value.Owning an item seems to increase its value in the owner’s mind.The endowment effect may play a role in the "east or west,home is best","no rotten peach in one’s basket" and "nail house" that the Chinese often refer to.In market transactions,the endowment effect is mainly manifested in two forms: one is that the owner is unwilling to exchange the item in hand for another equivalent item;Second,for the same item,the selling price(Willing-to-accept,WTA)that the owner can accept is often higher than the purchase price(Willing-to-pay,WTP).The study of endowment effect has important theoretical and practical significance.This is because the endowment effect contradicts the theoretical hypothesis of the traditional western mainstream economics,but it can provide a more reasonable explanation for the phenomena such as the shortage of market transactions and natural property rights.In addition,the endowment effect has a wide range of influences and can be found in the fields of politics,economy,market,law,agriculture and environment.Therefore,studying and mastering the development law of endowment effect will help us to understand and solve many practical problems.This study combed the theoretical and empirical research on the endowment effect and found that the endowment effect is a robust decision-making phenomenon.However,there is no widely accepted unified theoretical framework to explain the origin of the endowment effect.In recent years,more and more researchers began to agree with the "evolutionary advantage hypothesis",believing that the endowment effect is an evolutionary advantage.That’s because researchers have found that the endowment effect exists not only in adults,but also in children who have not yet developed strategic thinking and in non-human groups of primates.Moreover,the function of the brain is also evolutional.The medial prefrontal cortex(MPFC),nucleus accumbens(NAcc)and insula,the right inferior frontal gyrus and the middle frontal system all found to be associated with the endowment effect.However,most studies generally focus on explaining the endowment effect from the perspective of acquired factors,such as reference price,psychological ownership,information bias,etc.Few researchers further explore the endowment effect directly from the perspective of innate factors.Since genes can determine traits,studying a decision behavior from a genetic perspective is one way to verify whether the behavior is influenced by innate factors.In the area of decision-making,similar studies already exist,for example,the influence of genes on risk-blurring decisions,loss aversion and framing effect.However,the research on whether genes can influence the endowment effect is still unknown,and few researchers pay attention to this very important question.According to previous studies,DBH is a catecholamine-metabolizing biological synthetase whose main function is to catalyze the conversion of dopamine into norepinephrine.The single nucleotide polymorphism(SNP)rs1611115 has three genotypes,CC,CT and TT.Among them,TT genotype showed the lowest DBH enzyme activity,CT genotype showed the intermediate activity,and CC genotype showed the highest enzyme activity.A study of people with Autism has found that SNP rs1611115 of DBH gene can affect social interactions.Compared with CC genotype subjects,participants carrying the T allele showed a higher social score in the Autism Diagnostic Interview Revision(ADI-R),meaning lower levels of social interaction.Due to the fact that buying and selling is an interactive behavior among people in market transactions,the endowment effect can be regarded as a “Status-quo Bias”,a strong inertia to maintain the status quo and refuse to change.Therefore,people with the T allele are more likely to have lower social interaction intentions and are less likely to buy or sell goods,showing a higher endowment effect.In order to explore whether genes can influence the endowment effect,we conducted two experimental studies on Chinese college students,namely,behavioral experiment and genetic experiment.The purpose of behavioral experiments is to verify whether the endowment effect exists,thus laying a foundation for genetic experiments.In the first study,we adopted the "valuation paradigm" in the endowment effect paradigm as the experimental task.The items used were lottery tickets with different winning probabilities or expectations.The measurement method of endowment effect was "selling price-buying price",or "WTA-WTP".The experimental results showed that :(1)32 subjects generally showed significant endowment effect,WTA>WTP,which was consistent with the previous research results.(2)There was no significant difference in the participants’ reaction to buying or selling lottery tickets with different winning probabilities.In study 2,participants were first asked to bid on virtual lottery tickets and then to provide saliva for genetic testing.We focused on whether the single nucleotide polymorphism of the dopamine hydroxylase(DBH)gene rs1611115 could affect the intensity of the endowment effect.The measure of endowment effect is still "WTA-WTP".The experimental results show that :(1)360 Chinese college students generally show a very significant endowment effect,that is,"WTA>WTP",which is consistent with the previous research results.Moreover,the endowment effect is different at different levels of winning probability,and the endowment effect of extreme probability group(1% and 99%)is weaker than that of medium probability group(10% to 90%).(2)Rs1611115,a polymorphism of dopamine hydroxylase,has a significant effect on endowment effect.Compared with subjects with CC genotype,subjects with T allele(in this study,CT genotype)show a stronger endowment effect.This is in line with our experimental expectations.(3)We found no significant effect of gender on endowment effect,WTA and WTP.(4)The influence of monthly consumption amount on the endowment effect is marginal,but there is a trend: compared with the subjects with high monthly consumption amount,the subjects with low monthly consumption amount show a lower endowment effect.(5)There was no significant difference in the strength of endowment effect between subjects of different majors,such as liberal arts and science.To sum up,this study provides the first direct evidence that genes can influence the endowment effect,and also provides more direct evidence to support the hypothesis of evolutionary advantage of the endowment effect.Our results show that even a single nucleotide polymorphism of a gene can have an impact on complex human marketing activities.Future studies can further focus on the specific pathway of rs1611115 SNP of DBH gene affecting the endowment effect,as well as the study on other related decision-making behaviors.Since some behavioral phenomena are often determined by multiple genes,it is also a good idea to conduct further joint research with other gene locus. |
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