Positive contact between members of different groups reduces prejudice and increases cooperation, findings known as intergroup contact effects. Yet in real-world settings not only positive, but also negative intergroup contact occurs, which have opposing effects. To date little is known about whether and how an individual's valenced history of intergroup contact influences contact effects and how this dynamic change happens during specific instances of intergroup contact. A pilot study examined the psychological impact of a novel paradigm to assess intergroup contact using a behavioral game. We then conducted two studies, which allowed us to observe a sequence of up to 23 in- and outgroup interactions and their behavioral outcomes in a continuous prisoner's dilemma behavioral game (N = 116, 2,668 interactions; N = 89, 1,513 interactions). As expected, participants showed a clear ingroup bias in expectations and cooperation. Furthermore, the quality of contact history moderated contact effects. Specifically, intergroup contact following a positive history of intergroup contact had a stronger effect on intergroup expectations than contact following a negative history thereof. Findings are discussed in view of the importance of considering the valenced history of intergroup contact, as well as new research questions on intergroup contact that can be addressed with this novel contact paradigm. (PsycInfo Database Record (c) 2022 APA, all rights reserved).