Properties of human affect induced by static color slides (IAPS): dimensional, categorical and electromyographic analysis.

Human affect elicited by static color slides was evaluated quantitatively using dimensional (N = 60 subjects) and differential or categorical (N = 57) self report, and facial electromyography (N = 20). Mean dimensional self reports of affective responses were highly replicable across cohorts. Mean categorical response profiles over seven affective categories were monomodal for some slides, but multimodal for most, and nearly identical within the same cohort for slides of similar content. Mean categorical response profiles for individual slides were also similar across different cohorts and for different experimental conditions. Valence calculated from weighted categorical self report scores was highly correlated with the self reported valence (r = +0.98), demonstrating a simple, linear relationship between dimensional and categorical (differential) measures of affect. Categorical response strength was synergically patterned, i.e. invariably correlated positively for affect of the same dimensional valence and generally correlated negatively for affect of opposite valence. Facial electromyograms associated with affective responses to slides were correlated with valence, but smaller in magnitude than those associated with the weakest possible voluntary facial movements involving the same muscles. This study, therefore, demonstrates that self reported affective responses to color IAPS slides are replicable within and between cohorts, complex but synergically patterned, and relatively weak.