This article proposes the concept of social‐affective product design to address the effects of product features on personal interactions. Using eyeglass frames as the target product, this study included a factorial experiment to evaluate design features concerning personality traits signified by facial shapes. The experiment involved extracting three representative types of facial shapes by sorting 60 photographs and constructing three‐dimensional models to rate attractiveness. The study then analyzed participant responses according to three social‐affective measures: approachability, assertiveness, and masculinity, evoked by faces wearing factorized eyeglass frames. Results show that increasing the levels of certain design features strengthens the impression of specific personality traits. © 2012 Wiley Periodicals, Inc.