Final answer:
Understanding human behaviour requires knowledge of developmental psychology, encompassing physical, cognitive, and psychosocial development, as well as considerations of nature vs. nurture, continuity and discontinuity, and moral development.
Step-by-step explanation:
Understanding and analyzing human behavior involves being knowledgeable about their development, including all aspects from the genetic makeup and biological traits we are born with, to the social interactions that shape our personalities and behaviors throughout life. This complex subject area is the specialty of developmental psychologists, who strive to understand how individuals change and grow during different stages of life - from conception to death.
Developmental psychology covers three domains: physical development, which includes changes in body and brain; cognitive development, which encompasses aspects such as learning, memory, and reasoning; and psychosocial development, concerning emotions, personality, and social relationships. Moreover, it's essential to differentiate between psychological and sociological theories of self-development and consider moral development as part of the understanding of human nature.
Furthermore, developmental psychologists contemplate three major issues in development, including continuity and discontinuity in development, whether there is a common course or multiple unique courses of development, and the ongoing debate of nature versus nurture. Knowledge in this field is not just academic; it has practical implications for personal decisions and public policy based on scientific research and understanding of human behaviour.