The standardization of a new Explicit Pornographic Picture Set (EPPS)

Abstract

Pictures with affective content have been extensively used in scientific studies of emotion and sexuality. However, only a few standardized picture sets have been developed that offer explicit images, with most lacking pornographic pictures depicting diverse sexual practices. This study aimed to fill this gap through developing a standardized affective set of diverse pornographic pictures (masturbation, oral sex, vaginal sex, anal sex, group sex, paraphilia) of same-sex and opposite-sex content, offering dimensional affective ratings of valence, arousal, and dominance, as well as co-elicited discrete emotions (disgust, moral and ethical acceptance). In total, 192 pornographic pictures acquired from online pornography platforms and 24 control IAPS images have been rated by 319 participants (M_age = 22.66, SD_age = 4.66) with self-reported same- and opposite-sex sexual attraction. Stimuli were representative of the entire affective space, including positively and negatively perceived pictures. Participants showed differential affective perception of pornographic pictures according to gender and sexual attraction. Differences in affective ratings related to participants' gender and sexual attraction, as well as stimuli content (depicted sexual practices and sexes). From the stimuli set, researchers can select explicit pornographic pictures based on the obtained affective ratings and technical parameters (i.e., pixel size, luminosity, color space, contrast, chromatic complexity, spatial frequency, entropy). The stimuli set may be considered a valid tool of diverse explicit pornographic pictures covering the affective space, in particular, for women and men with same- and opposite-sex sexual attraction. This new explicit pornographic picture set (EPPS) is available to the scientific community for non-commercial use.

Keywords: Affective ratings; Picture set; Pornography; Sexual attraction; Visual sexual stimuli.

Fig. 1

Pixelated example images of the EPPS categories showing sexual practices of M, O, V, A, G, P

Fig. 2

Schematic representation of a trial with a neutral IAPS control stimulus followed by the  assessed affective rating scales

Fig. 3

Distribution of the mean ratings obtained for EPPS and IAPS control images in the affective space of valence and arousal

Fig. 4

Bar charts of the affective ratings of shown sexual practices and sexes by gender and sexual attraction groups of the affective ratings of valence, arousal, dominance, disgust, and moral and ethical acceptance