Final answer:
Developmental psychologists study a range of human development issues across the lifespan and do not solely focus on unusual individuals. They examine physical, cognitive, and psychosocial development domains to understand how humans grow and change.
Step-by-step explanation:
Developmental psychologists generally do not focus their study exclusively on the unusual individuals to understand the extremes of human development. They study human growth and development across three developmental domains: physical, cognitive, and psychosocial. While it is true that case studies on exceptional individuals can provide deep insights into development, such an approach is not representative of the field as a whole. Developmental psychologists are more broadly interested in how all individuals develop throughout their lifespan. The discipline focuses on both typical and atypical development, with the goal of understanding the range of human developmental trajectories.
Moreover, developmental psychology addresses various questions about human growth, such as whether development is continuous or discontinuous, follows one course or many different courses, and the interactions between genetics and environment (nature versus nurture). The field encompasses several lifespan theories, and while focusing on exceptional cases can shed light on individual variability, it is not the sole focus for developmental psychologists.