1244 0097-0549/21/5109-1244 ©2021 Springer Science+Business Media, LLC Neuroscience and Behavioral Physiology, Vol. 51, No. 9, November, 2021 Quo Vadis, Chronopsychology? A. A. Putilov UDC 57.034+159.91 Translated from Zhurnal Vysshei Nervnoi Deyatel’nosti imeni I. P. Pavlova, Vol. 71, No. 2, pp. 244–269, March–April, 2021. Original article submitted November 22, 2020. Revised version received December 22, 2020. Accepted December 22, 2020. This is the first review in chronopsychology, a relatively new interdisciplinary area of research which has developed rapidly at the junction of chronobiology, somnology, and psychology. Chronopsychology studies the mechanisms of rhythmicity in behavior and the mind based on methods of chronobiology, somnology, and psychometry. In particular, chronobiology studies biological clocks, while somnology addresses their influences on regulatory processes directly controlling the sleep–waking cycle, impairments to which have adverse impact on mental activity. Psychometric and differential psychology methods are widely used, for example, in studies of the chronotype and its relationship with a great diversity of human characteristics – genetic, psychophysiological, behavioral, cognitive, personality, and psychopathological. Particular atten- tion is paid to sleep, drowsiness, fatigue, work/study productivity, and healthy/unhealthy lifestyles in people of different sexes and ages. Applied research includes the development – taking account of the chronotype of each specific person – of recommendations supporting preservation of good quality sleep and health in specific temporal situations, optimizing work/rest patterns, efficient assimilation of new skills, and prevent- ing accidents during vigorous activity at times of day unsuitable for these activities. Keywords: chronotypology, somnology, chronobiology, personality psychology, individual differences, circadian rhythms, regulation of the sleep–waking cycle, drowsiness, shift work. Introduction. The word “chronopsychology” is not hard to find in the vastness of the internet. It has been around for decades and since 1999 the Japanese hip-hop group M-Flo has performed a notorious song with this title. The paradox, however, is that it is much harder to answer the question of what constitutes the area of scientific research designated by the term “chronopsychology.” The answer is not obtained by listening to the song or from more serious studies of all biological sources containing this word. Among these, in particular, there are no reviews of the his- tory or current state of chronopsychology in either English or Russian. This is thus the first such review. Being a relatively young area of interdisciplinary re- search, chronopsychology has developed rapidly in recent years at the junction of chronobiology, somnology, and psy- chology. It addresses the mechanisms and manifestations of rhythmicity in behavioral and psychological processes. Its theoretical bases lie in two biological disciplines – chrono- biology and somnology. The area of experimental studies in the former of these disciplines includes biological clocks, while the latter addresses their influences on those regula- tory process directly controlling the sleep–waking cycle. Serious impairments to this cycle – and almost everyone is familiar with this – have adverse impacts on mental activ- ity, wellbeing, and mood. The theory and methodology of chronopsychology research are not linked solely with the biological sciences. Methods first developed in personality psychology (differential psychology) and which apply to the behavior of such psychological disciplines as psychom- etry and psychodiagnosis are widely used. An example of the wide use of these psychometric methods (an area of sci- ence linking psychology with mathematics and statistics) is provided by research into the chronotype (the type of daily rhythm) and its interaction with a great diversity of charac- teristics in humans – genetic, psychophysiological, cogni- tive, personality, psychopathological, etc. Specialists work- ing in chronopsychology pay special attention to working/ Federal Research Center for Basic and Translational Medicine, Novosibirsk, Russia; e-mail: putilov@ngs.ru. DOI 10.1007/s11055-021-01187-y