Gratitude expressions improve teammates' cardiovascular stress responses.

Gratitude expressions play a key role in strengthening relationships, suggesting gratitude might promote adaptive responses during teamwork. However, little research has examined gratitude's impact on loose tie relationships (like coworkers), and similarly little research has examined how gratitude impacts physiological stress responding or biological responses more generally. The present research uses an ecologically valid, dyadic teamwork paradigm to test how gratitude expressions impact in vivo physiological challenge and threat stress responding, assessed via a challenge-threat index composed of cardiac output and total peripheral resistance. Compared with a control condition, teammates ( = 190) who were randomly assigned to a gratitude expression manipulation showed improved biological challenge-threat responses while jointly completing an acutely stressful collaborative work task (developing a product pitch), and later while completing an individual performance task (pitching the product). During the collaborative task, gratitude expressions buffered against threat responses; during the individual task, gratitude expressions amplified challenge responses. Analyses of cardiac output (CO) and total peripheral resistance (TPR) aided in determining how cardiac outflow versus vascular constriction/dilation contributed to these effects. The finding that gratitude expressions promote adaptive biological responding at the dyadic level contributes to a growing literature on the social functions of positive emotions and gratitude, specifically. The present results also have wider implications for physiological stress in performance tasks and suggest that workplace gratitude interventions can promote adaptive stress responding in teams. (PsycInfo Database Record (c) 2022 APA, all rights reserved).