The Relationship Between the Ability to Infer Another's Pain and the Expectations Regarding the Appearance of Pain Facial Expressions: Investigation of the Role of Visual Perception.

Although pain is a commonly experienced and observed affective state, it is frequently misinterpreted, which leads to inadequate caregiving. Studies show the ability at estimating pain in others (estimation bias) and detecting its subtle variations (sensitivity) could emerge from independent mechanisms. While estimation bias is modulated by variables such as empathy level, pain catastrophizing tendency, and overexposure to pain, sensitivity remains unimpacted. The present study verifies if these 2 types of inaccuracies are partly explained by perceptual factors. Using reverse correlation, we measured their association with participants' mental representation of pain, or more simply put, with their expectations of what the face of a person in pain should look like. Experiment 1 shows that both parameters are associated with variations in expectations of this expression. More specifically, the estimation bias is linked with expectations characterized by salient changes in the middle face region, whereas sensitivity is associated with salient changes in the eyebrow region. Experiment 2 reveals that bias and sensitivity yield differences in emotional representations. Expectations of individuals with a lower underestimation tendency are qualitatively rated as expressing more pain and sadness, and those of individuals with a higher level of sensitivity as expressing more pain, anger, and disgust. Together, these results provide evidence for a perceptual contribution in pain inferencing that is independent of other psychosocial variables and its link to observers' expectations. PERSPECTIVE: This article reinforces the contribution of perceptual mechanisms in pain assessment. Moreover, strategies aimed to improve the reliability of individuals' expectations regarding the appearance of facial expressions of pain could potentially be developed, and contribute to decrease inaccuracies found in pain assessment and the confusion between pain and other affective states.