Investigating the role of prior cooperative experience on partner choice in Norway rats (Rattus norvegicus).

Reciprocators who meet an uncooperative individual can respond by engaging in partner control through adjusting their behavior toward this partner accordingly, engaging in partner choice by avoiding this partner and approaching more cooperative partners, or doing both. However, few studies have explored the respective roles of partner control and choice within the same species. Here we asked whether Norway rats, who have been shown to engage in partner control in different reciprocal cooperation paradigms, also use partner choice to interact with conspecifics. Partner choice could be underpinned by a preference for cooperative partners (positivity bias), an aversion to uncooperative partners (negativity bias), or a combination of both. Thus, we tested for these biases by first allowing focal rats to experience partners that differed in their level of cooperation during allogrooming. Thereafter, focal rats were given the choice to spend time either with the previously experienced more cooperative or less cooperative partners, or with neutral partners they had not interacted with for 40 min. Focal rats consistently preferred neutral partners over previous interaction partners and showed no difference in preference between more or less cooperative partners. Our results could be explained by a motivation to reunite with neutral partners, which could have overridden partner choice effects based on cooperation within the timeframe of the experiment. Further research is required to clarify the importance of partner choice to reciprocal cooperation in rats. (PsycInfo Database Record (c) 2026 APA, all rights reserved).