Does my pain affect your disgust? Cross‐modal influence of first‐hand aversive experiences in the appraisal of others’ facial expressions

Abstract

Background Embodied models of social cognition argue that others’ affective states are processed by re‐enacting a sensory‐specific representation of the same state in the observer. However, neuroimaging studies suggest that a reliable part of the representation shared between self and others is supramodal and relates to dimensions such as Unpleasantness or arousal, common to qualitatively different experiences. Here we investigated whether representations of first‐hand pain and disgust influenced the subsequent evaluation of facial expressions in Modality‐specific fashion, or in terms of Unpleasantness or arousal. Methods Thirty volunteers were subjected to thermal painful and olfactory disgusting events, and subsequently were asked to classify computer‐generated faces expressing pain (characterized by high Unpleasantness and arousal), disgust (high Unpleasantness and low arousal), surprise (low Unpleasantness and high arousal) and hybrid combinations thereof. Results Thermal and olfactory events were associated with comparable Unpleasantness ratings and heart rate (but stronger galvanic response was found for painful temperatures). Furthermore, we found that the appraisal of facial expressions was biased by the prior stimulus, with more frequent pain classifications following thermal stimuli, and more frequent disgust classifications following olfactory stimuli. Critically, this modulation was cross‐modal in nature, as each first‐hand stimulation influenced in comparable fashion facial traits diagnostic of both pain and disgust, without instead generalizing to features of surprise. Conclusion Overall, these data support the presence of shared coding between one's aversive experiences and the appraisal of others’ facial responses, which is best describable as supramodal representation of the Unpleasantness of the experience. Significance These results extend previous findings about common representational coding between the experience of first‐hand and others’ pain. In particular, they highlight that reliable part of the information shared is supramodal in nature and relates to a broad dimension of Unpleasantness common also to painless aversive states such as disgust.

Far from the eyes, far from the heart. COVID-19 confinement dampened sensitivity to painful facial features.

“…Indeed, the analyses of hybrid expressions reveal a dissociation between Cyberballinduced exclusion and the grouping factor, with the former triggering to a broad slowness in response times, and the latter instead leading to marginally faster choices for pain-neutral hybrids. Although we cannot draw conclusive interpretation of this specific result, in our previous study pain-neutral hybrids were particularly challenging for participants (> 3 sec; Antico et al, 2019), whereas here they were often classified as neutral (Table 1), and at higher speed especially after the lockdown (~ 1.5 sec; see Figure 5). This could be an additional argument that the grouping factor (but not Cyberball-induced exclusion) might explain variations in individual sensitivity to pain facial information, with post-lockdown individuals being more eager to dismiss the hybrid stimulus as neutral.…”

“…We ran a repeated measures ANOVA on both accuracy rates and response time of correct classifications. We found converging evidence of a main effect of Expression (Accuracy: F(2,98) = 62.20, p < 0.001, ηp 2 = 0.39; Response Times: F(2,98) = 157.278, p < 0.001, ηp 2 = 0.62), reflecting an overall difficulty at classifying pain and disgust faces with respect to neutral ones (Figure 4 A-B, see also Antico et al, 2019). More importantly, an Expression*Group interaction was observed in the analysis of Accuracy (Accuracy: F(2,196) = 3.94, p = 0.021, ηp 2 = 0.04; Response Times: F(2,98) = 2.58, p = 0.079, ηp 2 = 0.03; all other effects, Fs ≤ 1.94, ps ≥ 0.167, ηp 2 ≤ 0.02).…”

“…Disgust). Each hybrid stimulus was optimized to insure that it was as much ambiguous as possible, and that one state was not more easily detectable than the other (see Antico et al, 2019 for more details). Each of six facial expressions was applied on 30 artificial identities (15 males, 15 females), leading to an overall of 180 images.…”

“…Each gaming event was followed by a rapid sequence of five facial stimuli, corresponding to an overall of 90 expressions for each block (30 following each game condition). As in Antico et al (2019), each face was presented for 500 ms. At the bottom of the screen, we displayed the three response options, namely "NEUTRAL", "PAIN", and "DISGUST". Participants were asked to respond as more accurately as possible with no limit of response time, with "1", "2", or "3" keys of the keyboard.…”

“…This implies that representation of others' affect shares a representational level with that of basal somatic-affective experiences, possibly including mechanisms for motor reactions (Avenanti et al, 2005) and physiological/interoceptive regulation (Dirupo et al, 2020). More specifically, it has been shown that sensitivity to the others' pain expressions is heightened by previous exposure to a mild nociceptive stimulation (Antico et al, 2019;Coll et al, 2012;Godinho et al, 2012;Reicherts et al, 2013;Vachon-Presseau et al, 2011; see also Wieser et al, 2014, as a review), whereas it is inhibited by those same analgesic procedures that regulate first-hand pain, such as placebo or hypnosis . Our data fit this framework, as they show how a state of social sufferance, with potential hypoalgesic effect, can impede specifically the evaluation of facial traits which are diagnostic of pain, and not that of traits informative of other affective components (e.g., unpleasantness).…”