Complex sentence: Scott MacEachern writes that examination of the archaeological record does not support the claims made by these researchers; rather, it suggests that regional differences in IQ test score results need not be ascribed to variations in human evolutionary development.
Split into simpler sentences: Scott MacEachern writes that examination of the archaeological record does not support the claims. He therefore argued that regional differences in IQ test score results should not be ascribed to variations in human evolutionary development.