How does power manifest itself in everyday life? Using experiencesampling methodology, we investigated the prevalence, sources, and correlates of power in people's natural environments. Participants experienced power-relevant situations regularly, though not frequently. High power was not restricted to a limited few: almost half of the sample reported experiencing high-power positions. Positional power and subjective feelings of power were strongly related but had unique relations with several individual difference measures and independent effects on participants' affect, cognition, and interpersonal relations. Subjective feelings of power resulted more from within-participant situational fluctuation, such as the social roles participants held at different times, than from stable differences between people. Our data supported some theoretical predictions about power's effects on affect, cognition, and interpersonal relations, but qualified others, particularly highlighting the role of responsibility in power's effects. Although the power literature has focused on high power, we found stronger effects of low power than high power.positional power | subjective feelings of power | experience sampling | social roles | ecological setting P ower-asymmetric control over valued resources (1-4)-is a fundamental feature of human relations (5): individuals detect power differences quickly, recall them easily, and often prefer them to equality (6, 7). Although power plays a pivotal role in many aspects of life, from the workplace (1) to the family (8) to romantic relationships (9), little is known empirically about the course of power in everyday life. Without such data, it is unclear how power is experienced by individuals on a daily basis, including basic facts such as whether having or lacking power is a regular or rare occurrence and to what degree individuals fluctuate in their level of power throughout the day.Surveying the full array of power experiences occurring in real life also allows for a robust test of power theories. Most recent data on the psychological experience of power has focused on workplace environments and experimental power manipulations (10). Although such manipulations allow for causal attributions, the most common ones involve thinking about power (11) or anticipating power differences rather than experiencing them (12). Even when participants experience low-and high-power roles in the laboratory, these roles generally do not involve real decisions or consequential outcomes (13). Because the effects of power are known to change when power involves meaningful interpersonal interactions versus hypothetical scenarios or anticipated interactions (14), and when power differences are experienced as appropriate and legitimate versus arbitrarily assigned (15, 16), it is not a given that theories developed in the experimental laboratory will generalize to real-world power experiences. Furthermore, if power operates in aspects of life beyond work, it is important to determine if theories of power (3, 4) ho...