Date of Award

Spring 4-1-2021

Document Type


Degree Name

Doctor of Philosophy (PhD)



First Advisor

Santos, Laurie


Early human life is marked by robust developmental shifts in sociocognitive abilities. While we know a lot about these developmental patterns in human primates, we know relatively little about whether nonhuman primates share these early life trajectories. In this dissertation, I identify and explore three open questions using this comparative developmental psychology method. In Chapter 2 (Arre, Clark, and Santos, 2020), I compare the developmental trajectory of an early emerging theory of mind ability— the capacity to represent what others see— in a primate species to the existing established trajectory in human infants. In Chapter 3 (Arre, Stumph, & Santos, 2021), I look at the plasticity of this same capacity to represent what others see by comparing adults of two closely-related species that vary in their socioecology. These chapters together provide a new perspective on how early life experiences and varying socioecologies affect the emergence of visual perspective representing abilities. Finally, in Chapter 4 (Arre, Stumph, Hengartner, & Santos, in prep), I examine how macaques develop an entirely different social ability, gaze following, testing whether macaques share a human-like tendency to attend to the information given by more knowledgeable agents as compared to less knowledgeable agents. Across these three experiments, I find that despite some developmental delays (Chapter 2), the ability to represent what others see seems otherwise relatively adult-like even in early life, regardless of different socioecological input (Chapter 3), or agent that subjects are representing the perspective of (Chapter 4). Taken together, my findings suggest that as compared to human infants, young primates’ slowly developing social cognition might be a contributing factor to sociocognitive differences we see in adult human and nonhuman primates.