Over time, through many excavations such as Lake Mungo and Kow Swamp, Thorne made arguments that contradict traditionally accepted theories explaining the early dispersion of human beings.
The skull thickness of the "Mungo Lady" set, in particular, proved to be the most significant contradiction, as other uncovered Australian hominid specimens dated to approximately the same time period (about 25,000 years ago) have been tall and thick-skulled.
As a result of what had been uncovered at Lake Mungo, Thorne devoted a large amount of time and energy into constructing a theory that would prove that there had been only one human migration out of Africa and sought support from colleagues in various parts of the world.
"[4] For Thorne, the Lake Mungo study clearly demonstrated that instead of a second wave of Homo sapiens migration taking place approximately 100,000 to 120,000 years ago out of Africa, "regional continuity" occurred.
[6][7] Thorne played an influential role in the leading of the excavations at the Kow Swamp burial ground, 10 kilometres (6.2 mi) southeast of Cohuna in the central Murray Valley, Australia.
The excavations at Kow Swamp formed part of Thorne's PhD research and he is credited with providing Australian anthropology with the first ever fossil sets from established contexts – that is, from provenance and dating.
Furthermore, this work was combined with the many other excavations being undertaken in Australia and Asia during a similar time period that were exploring the possibility of multiregional human evolution, rather than the widely accepted "Out of Africa" theory.
[8] Studies performed on the Kow Swamp fossils led to the formulation of an alternate theory, as the bodies that were reconstructed proved to be structurally similar to modern humans, rather than the temporal era that was assigned to them.