Everyday social interaction is often dominated by categorical thinking, with generic group-based knowledge structures guiding people's dealings with others. Noting the important influence that category-cueing facial features exert during the initial stages of person construal, the current work explored the effects of hair cues on the process and temporal dynamics of sex categorization. Using a standard priming paradigm to index the products of person construal (i.e., categorical and stereotype- based knowledge), the results of three experiments revealed that: (i) hair cues alone are sufficient to trigger category and stereotype activation; and (ii) during the early stages of person perception, these cues have the capacity to reverse conventional priming effects and generate errors of categorical assignment (e.g., female faces prime male knowledge). These findings are considered in the context of contemporary accounts of person construal. Copyright © 2006 John Wiley & Sons, Ltd.