The book presents the study results of psychological states’ reflective regulation: conceptual ideas of its mechanisms, phenomenological features, influence of cognitive processes on reflective regulation, mental structures and personality traits. The book also analyzes situational and activity-related factors (everyday and stressful), specializationrelated factors and forms of educational activities. The effects of pregnancy and the music compositions of various directions on psychological states of individuals with different levels of reflection were found in the course of the study.