Abstract

We do not have direct interspecies measures of the intensity of valenced experiences. Still, we can explore some factors that might affect animals’ welfare ranges. This chapter explores those factors and, ultimately, explains why we have to rely on indirect proxies for variation. First, we consider what theoretical evolutionary biology can tell us about the function of valenced experience. Next, we explore how different aspects of intellectual and emotional complexity might affect the characteristic intensity of valenced experience. Finally, we explore potential neurobiological, behavioral, and physiological markers of the intensity of valenced experience in human and nonhuman animals.