Professor Byrne studies the evolution of cognitive and social behaviour, particularly the origins of distinctively human characteristics. Current projects focus on the acquisition of manual skills in great ape feeding, and the intelligence and cognition of the domestic pig. Previous work has included the ecology of baboon social structures, analysis of deception in primates, and the relation between brain size and intelligence.

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 range of monkeys and apes. Professor Byrne was awarded the British Psychology Society Book Award 1997 for his O.U.P. monograph The Thinking Ape.