Species and individual differences in communication based on private states

The way people come to report private stimulation (e.g., feeling states) arising within their own bodies is not well understood. Although the Darwinian assumption of biological continuity has been the basis of extensive animal modeling for many human biological and behavioral phenomena, few have attempted to model human communication based on private stimulation. This target article discusses such an animal model using concepts and methods derived from the study of discriminative stimulus effects of drugs and recent research on interanimal communication. We discuss how humans acquire the capacity to identify and report private stimulation and we analyze intra- and interspecies differences in neurochemical mechanisms for transducing interoceptive stimuli, enzymatic and other metabolic factors, learning ability, and discrimination learning histories and their relation to psychiatric and developmental disabilities.