It is suggested that previous research examining children's social categorization has relied on techniques which call upon controlled cognitive processes, that is, processes under voluntary control. As such, this research may say little about children's spontaneous categorization of social information. The present study introduces an unobtrusive measure of categorization which enables examination of automatic processing with respect to gender categorization - the ‘who said what?’ technique (Taylor, Fiske, Etcoff, & Ruderman, 1978). A sample of 84 children aged between 7 and 12 years were presented with four photographs, two of boys and two of girls, together with 16 statements attributed to each of the children (i.e. four statements to each child). Subsequently, 16 statement cards each had to be assigned to a particular photograph to indicate ‘who said what?’ Children made significantly more within-gender errors than between-gender errors, indicating that they had spontaneously assimilated social information to gender-based categories.