Differences in affordance-based behaviors within an isolated and confined environment are related to sleep, emotional health and physiological parameters

Astronauts are required to operate within isolated, confined and extreme environments (ICE). Isolated, confined and controlled (ICC) environments, such as the NASA Human Exploration Research Analog (HERA) site, provide ways of studying and predicting behavioral changes that occur in response to prolonged exposure to ICE environments. An important aspect of behavior is affordance perception. An affordance refers to a possibility for action. Affordance perception and related behavior may be affected by sleep, emotional health and stress. The inability to accurately perceive changes in affordances may increase the risk adopted during a task, possibly compromising mission success. Purpose: Investigate changes in affordance perception during a 30-day exposure to an ICC environment and investigate the relationship between affordance perception and sleep, emotional health and physiological markers of stress. Methods: Sixteen subjects completed five sessions of the perception-action coupling task (PACT), a novel tablet-based affordance perception task, on days 3, 10, 17, 24 and 5-days post-mission. The 15-min PACT presents a series of virtual balls and apertures varying in ball to aperture size ratio (B-AR) from 0.2 to 1.8. Subjects determined whether the ball could fit through the aperture and responded based on their perception of this action possibility. Participants also completed an emotional health questionnaire, the Mental Health Checklist (MHCL) throughout the mission. Actigraphy was used to collect sleep measures. Multiple ANOVA were conducted to assess changes in PACT response time (RT), accuracy (ACC) and lapses across time and to assess the role of individual differences in sleep, MHCL measures and salivary biomarkers of stress on performance. Results: A significant main effect of time was observed on PACT RT (F_{4, 60} = 3.631, p =.010, n²_p =.195) which was faster on day 24 (0.738 ± 0.088s) than day 17 (0.768 ± 0.092s). No differences were observed between other timepoints. ACC and lapses did not vary during the mission (p >.05). Individual differences in sleep duration, sleep efficiency, MHCL measures and salivary biomarkers related to individual differences in aspects of PACT performance. Conclusion: Modest changes in PACT performance were observed during a 30-day ICC exposure. Individual differences in performance may relate to individual differences in sleep and emotional health.