He is a cognitive psychologist with 21 years of experience working with nonhuman primates, young children, human adults, and other species such as birds, bears, and elephants. His research on self-control and future-oriented cognition has been supported by grants from the NIH and NSF. He is the editor or co-editor of eight major journals in the fields of comparative and cognitive science, and has published more than 150 peer-reviewed journal articles (and more than 250 total publications) on aspects of human and animal cognition, including dozens of papers on self-control.