[3] Davidson's initial research focused, under the direction of his mentor Frank Speck, on the eastern Algonquian, where he developed an archaeological approach.
Already with his doctoral dissertation however his deep interest in the indigenous population of Australia emerged as he applied the diffusionist model of the age and area theory to antipodean ethnographical materials.
Over this time, Davidson managed to gather a list of native vocabularies amounting to some 4200 words, collected from informants speaking 19 different languages of Western Australia.
[6] In 1938 he published A Preliminary Register of Australian Tribes and Hordes together with An Ethnic Map of Australia, a magisterial synthesis of his close sieving of the available ethnographic materials regarding Aboriginal groups.
[8] Davidson also retrieved unpublished manuscript material written by Edith Hassell on the myths of the Koreng tribe of Western Australia, and edited it for publication over 1934[9][10] and 1935.