Memory effect in expressed emotions during long term group interactions

Long-term interactions in groups can be monitored through games in which the participants need to show their social preferences by making choice to help or to use egoistic game strategy. In this paper we analyse the facial expressions of a group of isolated individuals (astronauts) during repeated interactions in subsequent encounters in a game. The astronauts were taking part in the Mars-500 isolation experiment and their relations were influenced by the everyday interaction in this untypical environment, and monitored through the cooperative game. We analysed different statistical properties of the recorded emotional facial expressions of the astronauts, where emotions were determined by the FaceReader software. We found that there is a memory effect between the collective emotional expressions corresponding to subsequent experiments, separated by two weeks time period. This dependance suggest that it is possible to predict the development of interpersonal relations in groups of isolated individuals. In a broader perspective, this finding can inform the design of long-term interaction behavior of artificial agents.