How Can Emotional Arousal Affect Decisions under Uncertainty?——From the Perspective of Decision Preferences
Decision preferences are consistent according to the traditional rational decision-making theories.However,there are many phenomena of preference reversal which rational decision-making theories cannot explain in real life.Therefore,more and more researches focus on the impact of emotions on decision-making.An agent's emotion can be measured according to valance and arousal,where valance refers to whether the emotion is positive or negative (eg.animated or unanimated) and arousal refers to the intensity of the emotion (eg.peaceful or excited).A large number of researches focused on the different impact of positive and negative emotions on decision-making from the dimension of valence in the past.But these phenomena still can't be well explained purely from the dimension of valence.So it's necessary to study the impact of emotions on decision-making from the dimension of arousal.The study aims to figure out whether emotional arousal is a reason of preference reversal.Previous studies have found that different numerical sizes could stimulate different emotion reactions and large numerical size was able to evoke more intense emotional reactions than small numerical size.Thus,we designed a money gambling game to explore how emotional arousal influences decisions made under uncertainty.Four types of pictures (2 × 2:risk vs.ambiguity ; large monetary amount vs.small monetary amount) were used as stimuli in our experiment.Pictures with a gray circle in the center represented ambiguous decisions whose probabilities remained unknown.And pictures with two shades of gray semi-circle in the center represented risky decisions whose winning and losing probabilities were both 50％.Besides,large monetary amount (150) indicated high arousal level while small monetary amount (20 ) indicated low arousal level.12 master candidates (7M/5F,age 22-27,all right-handed) participated in our event-related brain potentials (ERPs) experiment.The experiment,lasting for a total of 15-20 minutes,included six blocks of 48 trials each.All the stimuli were randomly presented and participants were asked to decide whether or not to bet according to the stimuli in the gambling.After finishing the ERPs experiments,subjects were required to participate in a questionnaire to detect their emotion levels when making different types of decisions.The research results showed that large monetary amount stimulated higher level of emotional arousal than small amount (t =11.661,P =0.000),reflecting that the level of emotional arousal can be influenced by monetary amount.The P3 amplitude evoked by ambiguity decision was significantly larger than that of risk decision in large amount condition (F (1,11) =9.800,P =0.010).In contrast,no significant difference for P3 amplitude was observed between ambiguity decision and risk decision in small amount condition (F (1,11) =0.014,P =0.908).Previous study considered that when confronting both ambiguous and risky decisions,people would prefer risk ones rather than ambiguity.However,our findings revealed that decision-making preferences could be affected by emotional arousal.When in high arousal level,decision-makers will prefer ambiguous decisions compared with risky decisions.But when decision-makers are in low arousal level,the preferences between risk and ambiguity don't differ significantly.The results revealed the internal mechanism of preference reversal and enriched the theory of emotion's influence on decision-making.Also,our conclusions are of great significance on the interpretation of preference reversal phenomena in real lives.
emotionsarousalpreference reversaldecisions under uncertainty
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