Barbara L. Fredrickson's article discusses the underrepresentation of positive emotions in psychological research and proposes a new model to explain their function. Positive emotions, such as joy, interest, contentment, and love, are argued to broaden an individual's momentary thought–action repertoire, thereby building physical, intellectual, and social resources. This model challenges traditional views that focus on negative emotions and suggests that positive emotions have adaptive value by promoting flexibility and creativity. The article highlights that positive emotions are less differentiated and have less specific action tendencies than negative emotions, which have been more studied. However, positive emotions may be more effective in regulating negative emotions and promoting well-being. The article also discusses empirical evidence supporting the broaden-and-build model, including studies showing that positive emotions expand attention, cognition, and action. Positive emotions are shown to enhance creativity, problem-solving, and learning, and to build physical and intellectual resources through play and exploration. The article concludes that positive emotions are essential for psychological well-being and that more research is needed to fully understand their role.Barbara L. Fredrickson's article discusses the underrepresentation of positive emotions in psychological research and proposes a new model to explain their function. Positive emotions, such as joy, interest, contentment, and love, are argued to broaden an individual's momentary thought–action repertoire, thereby building physical, intellectual, and social resources. This model challenges traditional views that focus on negative emotions and suggests that positive emotions have adaptive value by promoting flexibility and creativity. The article highlights that positive emotions are less differentiated and have less specific action tendencies than negative emotions, which have been more studied. However, positive emotions may be more effective in regulating negative emotions and promoting well-being. The article also discusses empirical evidence supporting the broaden-and-build model, including studies showing that positive emotions expand attention, cognition, and action. Positive emotions are shown to enhance creativity, problem-solving, and learning, and to build physical and intellectual resources through play and exploration. The article concludes that positive emotions are essential for psychological well-being and that more research is needed to fully understand their role.