| Making decisions is common in our daily life.Others' choices are important factor that forms our social context.Different choices bring about different outcomes.Previous studies suggested that the consistency of choices between self and others may influence the participants' evaluation of their own choices.To investigate whether the consistency of choice may influence the outcome evaluation,we conducted two experiments.In the present studies,participants were instructed to make their own choices before(Exp 2)or after(Exp 1)observing the decision of the others' before the outcomes of their choices revealed.The current studies were exploratory,which separated choosing and feedback stages and showed that the consistency of choice can modulate the neural activities of outcome evaluation.Objective This study aimed to explore how the consistency of choice modulates the neural responses to the outcomes.Materials and Methods ERP is a technique to extract event related components from Electroencephalography(EEG)by amplifying and averaging trials.Corresponding brain regions elicit time-locking bioelectricities when certain stimuli are given to participants or when the brain is processing information.All the ERPs have specific waveforms and scalp locations.ERPs are elicited in fixed periods after related events.The experiments were programmed and displayed with E-prime 2.0.EEG data were recorded from a 64-electrodes scalp cap using the 10-20 system(Brain Products,Munich,Germany).The channel TP9 was used as the reference during recording.Ground was located at AFz site.HEOG was recorded from the outer canthus of right eye.ResultsExperiment 1The paired sample t-tests revealed that participants tend to make different choices from the others' p=0.037,t(15)=2.28.For the d FRN component,the main effect of choice consistency was significant,F(1,15)=6.81,p=0.020,?p~2=0.31.Specifically,consistent trials(-6.19±0.49?V)elicited larger d FRN amplitudes than inconsistent ones(-4.93±1.11?V).The main effect of electrodes was significant,F(8,120)=3.44,p= 0.030,?p~2=0.19,amplitudes on F1?Fz and F2 were larger than other chosen electrodes.For the P3 component,we found that the main effect of feedback was significant,F(1,15)=7.08,p=0.002,?p~2=0.32,positive outcome(8.39±1.60?V)elicited larger P3 amplitudes than non-outcome(6.31±1.42?V).The main effect of electrodes was significant,F(8,12)=9.65,p<0.001,?p~2=0.39,amplitudes on P3?Pz and P4 were larger than other electrodes.Experiment 2Participants' reaction time was 1.71 ± 0.92 s.For the dFRN component,the main effect of choice consistency was significant,F(1,18)=6.14,p=0.023,? p2=0.25.Specifically,consistent choices(-5.57±0.72?V)elicited larger d FRN amplitudes than the inconsistent ones(-2.62±0.60?V).The main effect of electrodes was significant,F(8,144)=3.22,p=0.032,?p~2=0.15.Amplitudes on F1?Fz?F2 and FCz were larger other electrodes.For the P3 component,the main effect of choice consistency was significant,F(1,18)=4.60,p=0.046,?p~2=0.20.Inconsistent choices(7.23±1.83?V)elicited larger P3 amplitudes than consistent choices(6.13±1.73?V).For the late positive potential(LPP),the main effect of choice consistency was significant,F(1,18)=13.77,p=0.002,?p~2=0.43,inconsistent choices(3.60 ± 0.98?V)elicited larger LPP amplitudes than consistent choices(2.65±0.91?V).Inconsistent choices(3.60 ± 0.98 ? V)elicited larger LPP amplitudes than consistent choices(2.65±0.91?V).The interaction effect between feedback outcome and electrodes was significant,F(8,144)=3.40,p=0.019,?p~2=0.16.Specifically,positive outcome(3.18 ±1.25?V)exerted larger LPP amplitudes than non-outcome(1.42 ± 1.14?V)at the electrode of Cz,whereas no significant differences were found in any other electrodes(ps>0.051).Conclusion Electrophysiological results found that in the early stage of outcome evaluation,no matter who made the choice first,when the two participants' choices were the same,a more pronounced d FRN was observed comparing to when their choices were different.In the later stage of outcome evaluation,only when the participant made his/her own choice before the confederate(in experiment 2),more positive P3 and LPP were observed when their choices were the same comparing to when their choices were different.Our data support that the consistency of choice between self and other does modulate the neural activity during outcome evaluation.Specifically,in the early stage of outcome evaluation,the consistent choice amplifies the neural response to negative outcome reflected in the enlarged d FRN in the consistent context.In the later stage,when the participant made the choice first and saw the other one choose a different option,the sense of conflict would be induced along with negative feelings.Therefore the participant would spend more mental resource to process this conflict in order to avoid it in the further.This effect reflected in the enlarged amplitudes of P3 and LPP in the inconsistent context.Our finding provides some insights into how social context influences the psychophysiological processes in outcome evaluation. |
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