Numerous　studies　have　reported　deficits　in　non-social　decision-making　tasks　and　reward-related　impulsivity　in　individuals　with　problematic　Internet　game　use　(PIGU).　However,　those　findings　may　not　generalize　to　situations　that　involve　social　interactions.　Therefore,　this　study　aimed　to　examine　how　PIGU　may　relate　to　behavior　during　cooperative　dilemmas　and　the　potential　moderating　influences　of　social　distance.　Twenty-three　subjects　with　PIGU　and　23　with　occasional　Internet　game　use　(OIGU)　were　recruited　to　participate　in　the　experiment.　Participants　played　League　of　Legends　cooperatively　with　one　of　their　real-life　friends　and　one　strange　confederate　game-mate　under　non-face-to-face　conditions,　and　then　completed　Prisoner＇s　Dilemma　(PD)　and　Chicken　Game　(CG)　tasks　with　their　friend,　game-mate,　and　stranger,　respectively.　Results　showed　no　between-group　difference　on　cooperation　in　the　PD,　but　participants　with　PIGU　(as　compared　to　those　with　OIGU)　exhibited　lower　cooperation　during　the　CG.　Compared　with　friends　and　stranger　partners,　short-time　cooperation　in　online　gaming　did　not　improve　cooperation　toward　game-mates　in　the　PD,　but　elevated　cooperation　in　the　PIGU　group　toward　game-mates　in　the　CG.　The　results　of　this　work　suggest　that　risk-taking-related　preferences　in　individuals　with　PIGU　may　extend　to　some　aspects　of　social　decision-making.　©　2018　Elsevier　Ltd