Human content in affect-inducing stimuli: A secondary analysis of the international affective picture system

We report a secondary analysis of the international affective picture system (IAPS), the broadest available standardized sample of emotional stimuli, which confirmed our prediction that the distribution of slides across the valence and arousal dimensions would be related to human versus inanimate slide content. Pictures depicting humans are over-represented in the high arousal/positive and high arousal/negative areas of affective space as compared to inanimate pictures, which are especially frequent in the low arousal/neutral valence area. Results pertaining to dominance ratings and gender differences in valence and arousal ratings further suggest that there are qualitative differences between emotional reactions to animal or human slide content and responses to nonsocial still photos. Researchers need to be mindful of this distinction when selecting affect-inducing stimuli.