The FMRI Studies On Regret And Subsequent Behavior In A Sequential Risk Taking Task

The wide application of non-invasive brain imaging technologies,especially functional magnetic resonance imaging(fMRI),enabled human beings to understand the pattern of their own brain activations,and spawned a new branch of discipline—social cognitive neuroscience.The current dissertation focused on the emotion of regret with the technology of fMRI.As one of most commonly experienced social emotion,regret is an impressive topic in the field of social cognitive neuroscience.It is produced from counterfactual thinking,which requires one to mentally juxtapose the representations of ‘what might have been' and what has actually occurred.Individuals experience regret if the factual outcome of their choice is worse than that of the rejected alternatives.Regret is always seen as a negative emotion that one shall cope with.Long-term experience of regret,for instance,might have negative influence on mental health and subjective well-being.But on the other hand,regret also accompanies adaptive behavior changes,which means individuals could learn from the regretful experience to optimize future behaviors.Earlier fMRI studies on regret usually adopted the stand-alone task called‘wheels of fortune'.However,besides such simple,stand-alone decisions,individuals are frequently required to make many sequential risky decisions.To address this issue,Brassen and colleagues(2012)employed a modified version of the sequential risk-taking task.During the task,participants were asked to open a series of boxes consecutively and decide when to stop.All except for one box contained a reward(gold);the remaining box contained an adverse stimulus(devil)that caused participants to lose all the gold that had been collected in that trial.When participants decided to stop,the position of the devil was shown,revealing the number of collected gains and missed chances.In the study,researchers used missed chances to represent regret.However,as a subjective feeling,regret could not be represented by objective outcome directly.The current study extended the scale used for rating subjective emotions,and then to investigate the relationship between missed chances and regret by combining objective outcome and emotional rating.With four fMRI studies,the current dissertation focused on the following scientific issues.(1)In order to precisely investigate neural correlates of regret,study1 distinguished between regret and relief,which were two different emotions might result from counterfactual thinking.(2)Given the fact that regret was produced in social situations and was modulated by social factors,study 2 investigated the impact of social comparison on the neural processes of regret and subsequent behavior.(3)It is particularly important to regulate regret in due time.Study 3 focused on the impact of attentional deployment on the neural responses to regret.(4)Growing evidence reviewed that mind-body exercise was an effective way to improve individuals' emotional regulation.Study 4 investigated the effect of long-term Tai Chi exercise on the regret and regret-related brain regions by comparing Tai Chi and control groups.Study 1 found regret and relief were two different social emotions.Behaviorally,regret was mainly affected by missed chance and could induce risky subsequent behavior.Relief was primarily dependent on the trade-off between obtained gain and missed chance and could induce cautious subsequent behavior.At the neural level,regret was negative correlated with activation of ventral striatum(VS).Meanwhile,relief was correlated with activations of VS,vmPFC and pgACC positively.Study 2 investigated how social factor(i.e.,social comparison)affect the neural responses to regret and subsequent behavior.Except for verifying study 1's main results,study 2 found when doing better than others,participants felt less regret,took less risk,showed stronger activation of VS and showed higher VS-dACC functional connectivity.Additionally,the VS-dACC functional connectivity was correlated with subsequent behavior.Study 3 aimed to explore whether attentional deployment could modulate regret and related brain activities.Attentional deployment was manipulated by inducing participants to focus on obtained gain or missed chance of the outcome.Behaviorally,the results found when focusing on obtained gain,participants rated less regret,took less risk in subsequent behavior and showed stronger activations of VS and frontal gyrus.The enlightenment of study 3 was that focusing on obtained gain of the outcome could help individual to escape from regret effectively.Study 4 investigated the effect of long-term Tai Chi exercise on neural responses to regret by comparing Tai Chi and control groups.Besides the difference in Tai Chi exercise experience,two groups were balanced in terms of gender,age,education,physical exercise time per day and so on.Behaviorally,Tai Chi group showed higher level of meditation and emotional stability,less regret and risk-taking.On the neural level,Tai Chi group showed stronger fronto-striatal functional connectivity in poor relative to optimal outcome.The level of meditation mediated the impact of fronto-striatal functional connectivity on Tai Chi practitioners' emotional stability.In general,by combining fMRI and a sequential risk taking task,the current work demonstrated the origin,impacts and modulation of regret on both behavioral and neural level.Firstly,the current work successfully dissociated regret from relief in the task.The results showed regret was primarily dependent on missed chance,could induce risky subsequent behavior and was associated with VS.Moreover,the modulation of social comparison on regret,subsequent behavior,the activation of VS and VS-dACC functional connectivity were revealed.The current work also tried to explore the methods of regret regulation.The result clarified focusing on obtained gain of the outcome could reduce regret effectively and frontal gyrus played a key role in the regret regulation.At last,the current work found long-term Tai Chi exercise was effective for individuals to improve meditation and regret regulation by strengthening fronto-striatal functional connectivity.