Final answer:
Developmental psychology connects normal human growth studies with the research on special needs, focusing on physical, cognitive, and psychosocial development across the lifespan.
Step-by-step explanation:
The field that links usual development to the study of special needs is developmental psychology. Developmental psychology is a branch of psychology that studies human growth and development across different stages of life. This includes physical, cognitive, and psychosocial development. Developmental psychologists explore how individuals develop physically, cognitively, and socially throughout their lifespan, and they also focus on the normative development of individuals to understand when most children reach specific developmental milestones. Out of the three domains—physical, cognitive, and psychosocial development—the one not being asked about in the question is psychosocial development. This domain encompasses the emotional, personality, and social relationship aspects of development. Neuroscience disorders, such as autism spectrum disorder and attention deficit/hyperactivity disorder, highlight how developmental psychology can overlap with studies on special needs, as these disorders can affect the aforementioned domains.