Professor Byrne studies the evolution of cognitive and social behaviour, particularly the origins of distinctively human characteristics. Current projects focus on the gestural communication of great apes, and convergences in cognition between primates and distantly related species such as the African elephant, in collaboration with Dr Lucy Bates. Previous work has included tactical deception in primates and its relationship to brain size and intelligence, welfare-related studies of cognition in the domestic pig, and the analysis of social learning and imitation.

Postgraduates under his supervision have recently worked on primate gestural and vocal communication, comprehension of mechanical tasks, manual feeding techniques, including the effect of disability on chimpanzees' feeding techniques, and cognitive control of navigation within the home ranges of monkeys and apes. Professor Byrne was awarded the British Psychology Society Book Award 1997 for his O.U.P. monograph The Thinking Ape.