The Development of the Individual, the Personality, the Subject of Activity, and Individuality During Adulthood and Aging

In the history of developmental psychology as a branch of psychological science, the characteristics of adults have served as standards against which the different periods of growth, maturation, and the shaping of the personality in childhood, adolescence, and youth have been measured. Adulthood itself has traditionally been regarded as a stable period. For example, the French psychologist E. Claperede [23] characterized maturity as a state of mental "ossification" in which development ceased. Ebbinghaus [56] distinguished three periods in the development of memory and regarded the period between the ages of 25 and 50 as invariable in terms of that particular mental function. Piaget [31] considered the principal stages in the development of intelligence to be the preschool and school-age periods, in which development of the operational mechanism of intellectual activity was completed.