Processing facial expressions of emotion: upright vs. inverted images
- 1School of Arts, Development and Health Education, Massey University, Palmerston North, New Zealand
- 2Institute for Leadership and Personal Management, University of St. Gallen, St. Gallen, Switzerland
- 3Department of Psychology, Liverpool Hope University, Liverpool, UK
We studied discrimination of briefly presented upright vs. inverted emotional facial expressions (FEs), hypothesizing that inversion would impair emotion decoding by disrupting holistic FE processing. Stimuli were photographs of seven emotion prototypes, of a male and female poser (Ekman and Friesen, 1976), and eight intermediate morphs in each set. Subjects made speeded Same/Different judgments of emotional content for all upright (U) or inverted (I) pairs of FEs, presented for 500 ms, 100 times each pair. Signal Detection Theory revealed the sensitivity measure d′ to be slightly but significantly higher for the upright FEs. In further analysis using multidimensional scaling (MDS), percentages of Same judgments were taken as an index of pairwise perceptual similarity, separately for U and I presentation mode. The outcome was a 4D “emotion expression space,” with FEs represented as points and the dimensions identified as Happy–Sad, Surprise/Fear, Disgust, and Anger. The solutions for U and I FEs were compared by means of cophenetic and canonical correlation, Procrustes analysis, and weighted-Euclidean analysis of individual differences. Differences in discrimination produced by inverting FE stimuli were found to be small and manifested as minor changes in the MDS structure or weights of the dimensions. Solutions differed substantially more between the two posers, however. Notably, for stimuli containing elements of Happiness (whether U or I), the MDS structure showed signs of implicit categorization, indicating that mouth curvature – the dominant feature conveying Happiness – is visually salient and receives early processing. The findings suggest that for briefly presented FEs, Same/Different decisions are dominated by low-level visual analysis of abstract patterns of lightness and edge filters, but also reflect emerging featural analysis. These analyses, insensitive to face orientation, enable initial positive/negative Valence categorization of FEs.
Keywords: facial expressions, emotion, inversion, Same/Different, signal detection theory, multidimensional scaling, categorization, featural analysis
Citation: Bimler DL, Skwarek SJ and Paramei GV (2013) Processing facial expressions of emotion: upright vs. inverted images. Front. Psychology 4:54. doi: 10.3389/fpsyg.2013.00054
Received: 01 September 2012; Paper pending published: 01 October 2012;
Accepted: 24 January 2013; Published online: 14 February 2013.
, Palo Alto VA and Stanford University, USA
Copyright: © 2013 Bimler, Skwarek and Paramei. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in other forums, provided the original authors and source are credited and subject to any copyright notices concerning any third-party graphics etc.
*Correspondence: David L. Bimler, School of Arts, Development and Health Education, Massey University College of Education, Centennial Drive, Palmerston North 4442, New Zealand. e-mail: firstname.lastname@example.org