Theories differ on how typicality and arousal influence aesthetic appraisal and whether these processes together interact or have independent effects on aesthetic appraisal. This research investigates the simultaneous effects of typicality and arousal on aesthetic appraisal for product designs by manipulating both processes separately: typicality by prototype deviation and arousal by colour saturation levels. We demonstrate that typicality has a curvilinear relationship with aesthetic appraisal. Additionally, arousal has a positive linear relationship with aesthetic appraisal of product designs. Moreover, arousal can influence aesthetic appraisal independent from typicality.