International Affective Picture System

Normative Ratings

It is the essential property of the IAPS that the stimulus set is accompanied by a detailed list of average ratings of the emotions elicited by each picture. This shall enable other researchers to select stimuli eliciting a specific range of emotions for their experiments when using the IAPS. The process of establishing such average ratings for a stimulus set is also referred to as standardization by psychologists.

The normative rating procedure for the IAPS is based on the assumption that emotional assessments can be accounted for by the three dimensions of valence, arousal and dominance. Thus, participants taking part in the studies that are conducted to standardize the IAPS are asked to rate how pleasant/unpleasant, how calm/excited and how controlled/in-control they felt when looking at each picture. A graphic rating scale, the Self-Assessment Manikin (SAM), is used for this rating procedure.

Original norms

The official normative ratings for the IAPS pictures were obtained from a sample of 100 college students (50 women, 50 men, presumably predominantly US-American) who each rated 20 sets of 60 pictures. The rating was carried out in groups using paper-and-pencil versions of the SAMs. Pictures were presented for 6 seconds each; 15 seconds were given to rate the picture. Average valence, arousal and control/dominance ratings are available for the overall sample, and with men or women broken out separately.

Normative ratings were also obtained from children ages 7–9 years, 10-12, and 13-14. The rating procedure for children was mildly adapted; among other modifications, children were tested in classrooms, given instructions in a more child-friendly language, and they were allotted 20 seconds to rate each picture instead of 15.

Norms from further studies

Researchers from institutes other than the National Institute of Mental Health have also conducted studies to establish normative ratings for the IAPS in languages other than English and cultures other than US-American culture including Hungarian, German, Portuguese, Indian, and Spanish. One of these studies also included older participants (63–77 years).