Early in this century during an expedition to the Torres Straits, W.H.R. Rivers did some experimental work on the perception of geometric illusions among the Todas people of that region. Since that time other workers have investigated the extent to which geometric illusions are universally perceived. Most extensive of these studies is the work carried out by Segall , Campbell and Herskovits over a period of six years administering tests to 1878 people in widely dispersed groups - in different parts of Africa, one group in the Philippines, an American under graduate group and some adults in Illinois.