Human　social　decision-making　is　significantly　modulated　by　previous　decision　outcomes.　Using　event-related　potentials　(ERPs),　we　examined　whether　ERP　components　evoked　by　outcome　feedback　could　serve　as　electrophysiological　indices　to　examine　the　influence　of　current　outcome　evaluation　on　subsequent　cooperative　or　aggressive　decision-making.　Thirty-four　adult　volunteers　participated　in　a　social　game　task,　in　which　they　were　asked　to　choose　between　cooperation　and　aggression　with　an　opponent　player.Conventionally-averaged　ERPs　and　temporospatial　principal　components　analysis　(PCA)　factors　were　tested　for　their　associations　with　subsequent　decision-making.　Results　revealed　that　a　central-parietal　late　positive　potential　(LPP)　and　central-parietal　PCA　factor　approximating　the　classic　LPP　were　related　to　changes　of　decision-making　strategies　on　subsequent　trials;　however,　the　effect　was　significant　only　when　the　opponent　selected　＇cooperate＇　in　the　initial　trial.　The　decision　to　cooperate　in　subsequent　trials　induced　a　larger　LPP　relative　to　the　decision　to　aggress　following　opponent　cooperation　in　the　initial　trial.　Furthermore,　we　found　that　larger　LPP　amplitudes　for　an　opponent＇s　cooperative　decision　on　the　initial　trial　were　associated　with　a　higher　probability　of　choosing　cooperation　on　the　subsequent　trial.　The　results　suggest　that　the　amplitude　of　the　central-parietal　LPP　is　an　electrophysiological　index　of　the　influence　of　initial　outcome　on　subsequent　social　decision-making.