Sweet Emotion: The Role of Odor-induced Context in the Search Advantage for Happy Facial Expressions

Ljubica Damjanovic, Heather Wilkinson, Julie Lloyd
2017 Chemical Senses  
27 The current study investigated the extent to which the concurrent presentation of pleasant and 28 unpleasant odors could modulate the perceptual saliency of happy facial expressions in an 29 emotional visual search task. Whilst a search advantage for happy faces was found in the no 30 odor and unpleasant odor conditions, it was abolished under the pleasant odor condition. 31 Furthermore, phasic properties of visual search performance revealed the malleable nature of 32 this happiness
more » ... e. Specifically, attention towards happy faces was optimized at the 33 start of the visual search task for participants presented with pleasant odors, but diminished 34 towards the end. This pattern was reversed for participants in the unpleasant odor condition. 35 These patterns occur through the emotion-inducing capacities of odors and highlight the 36 circumstances in which top-down factors can override perceptually salient facial features in 37 emotional visual search. 38 39 Keywords: olfactory perception; emotions; happiness; facial features; visual search 40 were required to complete a forced-choice decision task categorizing facial expressions of 65 SEARCH ADVANTAGE FOR HAPPY FACES 4 happiness and disgust taken from the Ekman and Friesen (1976) database. Each facial 66 expression was individually presented at central fixation on the computer screen and 67 participants were required to identify, by button press, as quickly as possible the 68 emotional expression portrayed. In a between-subjects design, some of the participants 69 performed the task whilst they were exposed to a pleasant odor whilst another group of 70 participants performed the task whilst they were exposed to an unpleasant odor. A third 71 group of participants also performed the task under neutral (i.e., no odor) conditions. 72 Whilst there was an overall advantage for categorizing happy facial expressions, this 73 varied as a function of the odor context, such that the categorization of happy faces was 74 facilitated in the context of pleasant odor relative to the no odor control condition, but 75 impaired when presented with an unpleasant odor. The different odor contexts did not 76 affect the processing of facial expressions of disgust. These findings suggest that whilst 77 some facial expressions may be easier to recognize on the basis of unique low-level 78 features, such as the brightness of a smile in happy facial expressions, their perception is 79 nonetheless affected by the context in which it is encountered. In the case of Leppänen 80 and Hietanen's (2003) findings, the authors propose that the improved recognition of 81 happy faces in the pleasant odor context is achieved by increasing the accessibility of 82 positive emotions, which in turn enhances the perceptual processing of emotion-congruent 83 aspects of the facial signal. 84 Building on this important work, Leleu et al. (2015) discovered that some emotional 85 expressions are affected more strongly by different odor contexts than others. For 86 instance, facial expressions of anger and disgust were perceived correctly at lower 87 stimulus intensities when presented in an aversive odor context (i.e., butyric acid) than in 88 both the pleasant (i.e., strawberry) and no odor contexts. The perception of happiness was 89 achieved at lower stimulus intensities when presented in the pleasant odor context than in 90 SEARCH ADVANTAGE FOR HAPPY FACES 5 the control and aversive contexts. However, participants were not significantly influenced 91 by the different odor contexts in their perceptual judgments of fear and sadness. Whilst
doi:10.1093/chemse/bjx081 pmid:29293901 fatcat:zkhns2bqjrepjhykjxp7lbe2wa