Tafforin C. Time effects, cultural influences, and individual differences in crew behavior during the Mars-500 experiment. Aviat Space Environ Med 2013; 84:1082–6. Introduction: This note provides an overview of salient factors that could have an impact on the behavior of a crew in an isolated and confined environment during a very long-term adaptive process. We present the Mars-500 experiment, which took place in Moscow, Russia, over 520 d from June 5, 2010, to November 4, 2011. It was designed to simulate a 250-d interplanetary mission from Earth to Mars, a 30-d orbital stay with a Mars landing, and a 240-d interplanetary mission from Mars back to Earth. The six-person crew was composed of three Russians, two Europeans, and one Chinese. Methods: We applied the ethological method based on observation, description, and quantification of nonverbal behavior expressed by actions and interactions, as well as verbal behavior expressed through positions and communications. These events were scored with The Observer XT® software from video recordings made every 2 wk during a daily life activity at breakfast time and every month during a group discussion task. Results: We show that the frequency of occurrences of personal actions, visual interactions, facial expressions and collateral acts are linked to certain phases, periods, and temporal points of the mission. Verbal communications in English and in Russian involve prevalent language associated with place preferences and preferential relationships among the crewmembers. Discussion: We found evidence that the Mars-500 crew behavior was dependent on time, culture, and the individual.