Final answer:
The reasoning related to how primate adaptations inform our understanding of ancestral human behavior is found in primatology, which explores both the physical and behavioral traits of primates and how they may have evolved to facilitate aspects of human development such as morality and social interactions.
Step-by-step explanation:
The reasoning that emphasizes the kinds of adaptations expressed by primates as models for ancestral human behavior is rooted in the study of primatology. This field investigates the behavioral and physical traits of primates, allowing anthropologists to understand the evolutionary adaptations that humanity shares with its primate cousins.
Primates, including our closest nonhuman relatives, show a wide array of adaptations attributed to arboreal life, such as rotating shoulder joints, big toes widely separated from other toes, stereoscopic vision, and larger brains compared to other mammals. Moreover, these features may also have implications for our understanding of early primate predatory behavior and the development of human morality and social behaviors, as suggested by researchers like Frans de Waal. Primatology also contributes to discussions on primate and human intelligence, technology, and cultural evolution.