Role of anthropologists to show differences are only on surface . Structuralism.
Surface structure
Easily observed variations.
Deep structure

How people behave- universal
All people have same human needs and emotions (biopsychological functionalism). All can experience, hunger, pain, stress, happiness, etc.
Marxists argue all societies have hierarchies whereby structural forces exploit disadvantaged groups (structural violence)
Feminists argue women in all societies are exploited by men
There are deep cultural differences (language, religion etc) which affect sense of 'self' and shared cultural 'truths'. Different habitus is formed over cultural experience (structural functionalism) Symbolism explains differences