A 5-emotions stimuli set for emotion perception research with full-body dance movements

Abstract

Ekman famously contended that there are different channels of emotional expression (face, voice, body), and that emotion recognition ability confers an adaptive advantage to the individual. Yet, still today, much emotion perception research is focussed on emotion recognition from the face, and few validated emotionally expressive full-body stimuli sets are available. Based on research on emotional speech perception, we created a new, highly controlled full-body stimuli set. We used the same-sequence approach, and not emotional actions (e.g., jumping of joy, recoiling in fear): One professional dancer danced 30 sequences of (dance) movements five times each, expressing joy, anger, fear, sadness or a neutral state, one at each repetition. We outline the creation of a total of 150, 6-s-long such video stimuli, that show the dancer as a white silhouette on a black background. Ratings from 90 participants (emotion recognition, aesthetic judgment) showed that intended emotion was recognized above chance (chance: 20%; joy: 45%, anger: 48%, fear: 37%, sadness: 50%, neutral state: 51%), and that aesthetic judgment was sensitive to the intended emotion (beauty ratings: joy > anger > fear > neutral state, and sad > fear > neutral state). The stimuli set, normative values and code are available for download.

Figure 1

Stimuli Creation Procedure. The stimuli creation procedure was based on previous work^,,–, and respected requirements of experimental control for dance stimulus materials^,. Choreography of the 30 sequences (of Western contemporary and ballet dance) took place prior to the recording session and was led entirely by the dancer in conversation with two of the authors with professional dance experience (JFC and LSE). Filming of the dance sequences took place at the Max-Planck-Institute for Empirical Aesthetics in Frankfurt/M. For filming, a Canon EOS 5D Mark IV camera was used, with a Canon EF 24–105 mm f/4 L IS USM lens (settings: e.g., framerate (raw) at 50fps and framerate (output) at 25 fps. White balance: 5000 k, shutter speed: 1/100 s, and ISO: 400. The video format: H.264, aspect ratio: 16:9, and resolution: 1920 × 1080). A standard 6 × 3 m chroma-key greenscreen background was used to allow for the creation of additional visual preparations of the stimuli, such as silhouette videos and blurred faces. For this, dedo-stage lights (7 dedo heads, dimmers and stands kit) were required to illuminate the entire greenscreen and to minimise shadows. Postproduction was done using Adobe After Effects 2019 and Adobe Premiere Pro 2019. All footage was trimmed to the exact start and end points of the movements. Each clip was rendered into a separate file in an uncompressed format and the title was added, as specified verbally by the dancer during the recording. Before saving, the sound tracks (speech and ambience noise) of the clips were removed. Using Adobe After Effects, “Keylight” effect was added to all files, and the background removed from each clip. The “Level” effect (setting: output black = 255) was further applied to each clip to colour the extracted foregrounds white (the visible dancer silhouette). “Opacity” keyframes were then added to the beginning and the end of each clip to allow for a fade-in and fade-out of each clip (8 frames). Finally, each clip was rendered as a separate file in H264 format. The dancer was Ms Anne Jung and her informed consent for publication of identifying information, images and film in an online open-access publication were obtained. A short video of the creation process is available here: https://www.youtube.com/watch?v=Eij40jtw8WE.

Figure 2

Emotion recognition accuracy across intended emotions. Mean and variability of emotion recognition accuracies for each emotion, based on participant-specific emotion recognition rates p values are Bonferroni-corrected. Dotted line illustrates chance level (100%/5 emotions = 20%)—all emotion categories were recognized above chance level on average. Stimuli expressing fear were recognized significantly less well than all other emotional categories, but still above chance.

Figure 3

Average intensity ratings for 5 emotion categories. Mean and variability of Intensity ratings for stimuli of each emotion category as intended by the dancer and the total. p values are Bonferroni-corrected.

Figure 4

Average beauty ratings for 5 emotion categories. Mean and variability of Beauty ratings of dance movements, shown for all emotions as intended by the dancer. p values are Bonferroni-corrected.