Stress awareness and decision-making under uncertainty: Gender-specific effects of mild hypoxia in the Iowa Gambling Task.

Decision-making under uncertainty is a key cognitive function that is sensitive to acute stress. While prior studies have documented gender-specific effects of stress (i.e., typically increased risk-taking in males and greater caution in females), such findings have primarily emerged in conditions where participants were aware of the ongoing stressor. The present study explored whether stress awareness modulates gender differences in risk-taking by manipulating participants' awareness of being under mild hypoxia (i.e., reduced oxygen availability), a systemic stressor that often goes unnoticed by individuals. Sixty-four participants completed the Iowa Gambling Task (IGT) under normoxic (fraction of inspired oxygen (FiO₂) = 20.9%) and mildly hypoxic (FiO₂ = 14.1%) conditions, with participants either being informed or uninformed about the stressor. Results indicated that when participants were aware of the stressor, males exhibited an increased selection of disadvantageous decks (corresponding to greater risk-taking in the IGT) under mild hypoxia, whereas females demonstrated a trend toward more cautious and advantageous choices. In contrast, when unaware of the stressor, both genders showed similar, modest increases in disadvantageous choices under hypoxia. These findings suggest that gender-specific coping strategies in risky decision-making are triggered by the conscious appraisal of stress, rather than by its mere physiological presence, and support theoretical models emphasizing the role of cognitive appraisal and internalized gender norms in shaping decision-making under stress.