The Internal Representation Questionnaire (IRQ) is designed to assess people’s subjective mode of internal representations, and to quantify individual differences in “modes of thinking” along multiple factors in a single questionnaire. Exploratory factor analysis identified four factors: Internal Verbalization, Visual Imagery, Orthographic Imagery, and Representational Manipulation. The primary motivation for the IRQ is to measure the extent to which people experience their thoughts in the form of language and use language to guide their thinking.