Cognitive Psychophysics and Mental Models

Abstract

With the increased emphasis on incorporating users' mental models in design of interfaces comes an increased need for instruments for measuring mental models. Two frequently-used instruments for measuring people's mental representations of physical space are drawing a map and rating the distances between pairs of points in the space. The assumption underlying the present research was that mental representations of space (M i) are transformed to become a subject's response (R i), yielding the following functions: Rdraw i = frd(M i) + e d (for drawing a map), Rrate i = fr(M i) + e r (for making category ratings), and Rnavigate i = fn(M i) + e n (for navigating). If each of these functions were equivalent, then the correlations among the different measurement methods should be high. Subjects either drew maps in two sessions, provided category ratings of the distances between pairs of locations in two sessions, or drew maps in one session and rated distances in a second session. The correlations were significantly lower when subjects switched between rating and drawing than when they performed the same response in both sessions. These data suggest that the functions relating the mental representation to a response differ between drawing and rating. The discussion focuses on methods for measuring mental maps and the use of mental map data in designing spatial interfaces (including interfaces to information spaces).