MATTER in emotion research: Spanish standardization of an affective image set

Pictures with affective content have been widely used in the scientific study of emotions, from two main perspectives: on the one hand, dimensional theories claiming that affective experiences can be described according to a few fundamental dimensions such as valence and arousal, and on the other hand, discrete-category theories proposing the presence of a number of basic and universal emotions. Although it has been demonstrated that these two approaches are not mutually exclusive, the existing standardized affective picture databases have been created from the dimensional perspective, which has led to important gaps for research focused on discrete emotions. The present work introduces MATTER, a new database comprising 540 pictures depicting disgusting, fearful, neutral, erotic, mirthful and incongruent content, which provides normative values (total N = 368, mean = 120.47 ratings/picture) in valence and arousal dimensions, as well as in discrete affective (disgust, fear, erotica and mirth) and cognitive (incongruence and interest) features. A tentative classification into discrete categories is presented, and the physical properties of each picture are reported. Our findings suggest that MATTER constitutes a modern and suitable set of affective images including, for the first time, both mirth- and incongruence-related pictures. Additionally, it will enable the examination of affective and cognitive processes in fear/disgust and humor/incongruence fields.