This paper deals with the central themes in the cognitive orientation of the inhabitants of Erongarícuaro, a mestizo agricultural village of 2,400 people on the shore of Lake Pâtzcuaro, Michoacán, 250 miles west of Mexico City and in the ways in which these themes can be confirmed. The paper also demonstrates how the use of Thematic Apperception tests (in addition to the usual methods of participant observation by anthropologists) sharpens the fieldworker's insights and leads to a more logical and coherent interpretation of the data. Moreover, TAT responses have definite research value for the frequency of certain themes leads the fieldworker to search for overt manifestations of them in everyday life, manifestations whose significance might not be fully appreciated without cues given by the projective material.