Everyday stressors likely affect who we are and how we act, but there is little empirical evidence of this relationship. Here, we provide insight into the effects of stress on the Big Five personality states (Costa & McCrae, 1999). We start with an online experiment (N = 863) where we manipulate momentary stress. We find that momentary experiences of stress predict lower Extraversion, Agreeableness, Conscientiousness, Openness, and higher Neuroticism. We follow up with a smartphone-based longitudinal study (N=826 and approximately 18,000 momentary assessments). We find that, consistent with Study 1, momentary experiences of stress predict lower Extraversion, lower Agreeableness, and higher Neuroticism. However, we find that in this naturalistic setting, stress predicts higher Openness and does not predict Conscientiousness. We also show that stress predicts personality shifts above and beyond affect. Given the ubiquity of stress in daily life, it is important to understand its effect on people. By revealing how stress influences personality states, this research provides insight into managing stress and supporting others during challenging times.
