Trust,Risk And Social Preference

In this paper,we mainly studied a theme about the influence of risk and social preference over interpersonal trust and trustworthiness by laboratory and neuroscience experiments.Four classic games were performed to test whether risk preference and social preference could significantly influence the trusting behavior,revealing the nature of trust and trustworthiness.Specifically,we mainly discussed two questions as following:whether trust is a certain kind of investment decision involving risk concerns?Whether/how could social preference influence trust and trustworthiness?These two questions were tested and demonstrated by behavioral and neural evidence from laboratory and neuroscience experiments respectively.Firstly,we performed a laboratory experiment re-testing whether trust was significantly influenced by risk preference and social preference,and whether trustworthiness was significantly influenced by social preference.Specifically,we re-tested the relationships between trust,trustworthiness,risk preference and altruistic preference(one kind of social preference).In our laboratory experiment,we measured the trustor's trust and the trustee's trustworthiness,risk preference,trustor's altruistic preference and the trustee's altruistic preference through a trust game,a risk game,a triple dictator game and a standard dictator game respectively.Data analyses revealed that trustor's trust decision could not be explained by risk preference while trust and trustworthiness could be explained by altruistic preference of individuals.Based on the results revealed in laboratory experiment,we controlled and decomposed the influence of risk preference and altruistic preference over trust and trustworthiness,by performing neural experiments using newly developed technology of Neuroeconomics(transcranial direct current stimulation,tDCS).The purpose of our neural experiments was to clarify and reveal the nature of trust and trustworthiness by altering relative neural activities.Through modulating the right dorsolateral prefrontal cortex(rDLPFC,which is considered the brain region relating to selfish impulse control function)of our participants by tDCS temporarily,we revealed that enhancing the activity of the rDLPFC could alter risk preference of our participants without changing their trust decisions.The observations demonstrated that risk decision was causally related with the activity of brain region involving rational calculation,while no such causal relationship between trust and the activity of specific brain region was observed.The results of neural experiment demonstrated that trust is not a certain kind of risk decision involving rational calculations by clarifying that trust and risk behaviors have different neural basis.Moreover,by modulating the ventromedial prefrontal cortex(vmPFC,which is considered the brain region relating to empathy and altruistic motivations)of our participants by tDCS temporarily,we revealed that enhancing the activity of the vmPFC could alter both altruistic preference and trustworthiness of our participants.The observations demonstrated that trustworthiness of trustee was significantly influenced by altruistic preference,and the relationship between trustworthiness,altruistic preference and the activity of vmPFC was causally significant.The results of our neural experiment demonstrated that the nature of trustee's trustworthiness might be a kind of altruistic behavior which was significantly influenced by altruistic preference,adding new neural evidence which supports the Theory of Social Preference.Concerning the nature of trust,the relationship between trust and altruistic preference was significant in our laboratory experiment while no significant causal relationship between trust and the brain activity of altruistic related brain region was observed in our neural experiment.Since trustor's trust was influenced by different preferences and was modulated by different brain regions,involving inner deep brain areas such as the amygdala and the striatum,we should control and decompose these preferences by performing laboratory and neural experiments,revealing the nature of trust in further studies.