at ‧ a ‧ vis ‧ tic /ˌætəˈvɪstɪk◂/ BrE AmE adjective formal
[ Date: 1800-1900 ; Origin: atavism 'being like ancestors' (19-21 centuries) , from French atavisme , from Latin atavus 'ancestor' ]
atavistic feelings are very basic human feelings that people have felt since humans have existed