 Since the early 1970s, scientists have studied these four species in depth, finding potential cultural attributes within group dialects, foraging, and migratory traditions.Hal Whitehead, a leading cetologist, and his colleagues conducted a study in 1992 of sperm whale groups in the South Pacific, finding that groups tended to be clustered based on their vocal dialects.The differences in the whales' songs among and between the various groups could not be explained genetically or ecologically, and thus was attributed to social learning.