Exploring attentional biases towards facial expressions of pain in men and women

Documenting Race and Gender Biases in Pain Assessment and a Novel Intervention Designed to Reduce Biases

Disparities in pain care are well-documented such that women and people of color have their pain undertreated and underestimated compared to men and White people. One of the contributors of the undertreatment of pain for people of color and women may be the inaccurate assessment of pain. Understanding the pain assessment process is an important step in evaluating the magnitude of and intervening on pain disparities in care. In the current work, we focus on documenting intersectional race and gender biases in pain assessment and present the results of a novel intervention for reducing these biases. Across 3 studies (N = 532) and a mini meta-analysis using real videotaped people in pain as stimuli, we demonstrate that observers disproportionately underestimated women of color's pain compared to all other groups (men of color, White women, and White men). In study 3 (N = 232), we show that a novel intervention focused on behavioral skill building (ie, practice and immediate feedback) significantly reduced observers' pain assessment biases toward marginalized groups compared to all other types of trainings (raising awareness of societal biases, raising awareness of self-biases, and a control condition). While it is an open question as to how long this type of intervention lasts, behavioral skills building around assessing marginalized people's pain more accurately is a promising training tool for health care professionals. PERSPECTIVE: This article demonstrates the underestimation of pain among people of color and women. We also found support that a novel intervention reduced observers' pain assessment biases toward marginalized groups. This could be used in medical education or clinical care to reduce intersectional pain care disparities.

The value of the International Association for the Study of Pain to career development: perspectives of trainee and early career members

ABSTRACT

Supporting its young members has been a key priority of the International Association for the Study of Pain (IASP) for the past 5 decades. The IASP, along with its federations, chapters, and special interest groups, has provided benefits to its trainee and early career members for their career development. This article summarizes various key IASP initiatives and benefits offered to IASP members and how these benefits have positively impacted their careers, including examples from the authors of this article. Suggestions are made for future directions that the IASP could implement to enhance the value provided to its trainee and early career members, which will in turn contribute to IASP achieving its mission to stimulate and support the study of pain and to translate that knowledge into improved pain relief worldwide.

Pain-related stigma as a social determinant of health in diverse pediatric pain populations

Pediatric patients with invisible symptomology, such as chronic pain syndromes, are more likely to experience pain-related stigma and associated discrimination by others, including medical providers, peers, school personnel, and family members. The degree of this pain-related stigma may depend on several social dimensions, including observer (e.g., attentional and implicit biases) and patient characteristics (e.g., racial identity, socioeconomic stressors). In this mini-review, we introduce the concept of pain-related stigma, and the intersectionality of stigma, within the context of social determinants of health in pediatric pain populations. Stigma theory, observer attentional biases, healthcare provider implicit/explicit biases, adverse childhood experience, and psychophysiology of socio-environmental stressors are integrated. Several ethical, clinical, and research implications are also discussed. Because the study of pain-related stigma in pediatric pain is in its infancy, the purpose of this conceptual review is to raise awareness of the nuances surrounding this social construct, propose avenues through which stigma may contribute to health inequities, present frameworks to advance the study of this topic, and identify areas for further investigation.

Comparing the Effects of Thought Suppression and Focused Distraction on Pain-Related Attentional Biases in Men and Women

Increasing attentional focus away from pain can affect pain experience, suggesting that cognitive strategies that move attentional allocation may be a moderator of pain. In a pre-post-design, the present study examined the effects of 2 cognitive strategies used in pain contexts, thought suppression and focused distraction, on subsequent pain-related attention. Thought suppression was hypothesized to increase pain-related attention, whereas focused distraction was expected to reduce it. Influences of both anxiety and sex were also considered, as secondary questions. 139 (86 women, 53 men) healthy, pain-free participants were randomly assigned to use either thought suppression or focused distraction during a mild cold pressor test (CPT). Pain-related attention was examined using a dot-probe and an attentional blink task, pre-and post-CPT. Questionnaires about relevant cognitive and emotional aspects, demographics, and pain were completed. Results showed no difference in the effect of the 2 pain inhibition strategies on pain-related attention. The hypothesized rebound effect in thought suppression on pain-related attention did not emerge. However, thought suppression showed a short-term benefit in comparison to focused distraction regarding reported pain and perceived threat during the cold pressor test. Few sex differences were found. Thus, the cognitive strategies affected pain outcomes, but did not influence pain-related attention. PERSPECTIVE: Cognitive strategies could help with pain through changing attention allocation. In this study, the effects of the 2 cognitive strategies thought suppression and focused distraction on pain-related attention in men and women were examined. Elucidating mechanisms that lie behind pain strategies that focus on changing attention may help improve treatments.

Association between attentional bias to experimentally induced pain and to pain-related words in healthy individuals: the moderating role of interpretation bias

ABSTRACT

Attentional bias to pain-related information may contribute to chronic pain maintenance. It is theoretically predicted that attentional bias to pain-related language derives from attentional bias to painful sensations; however, the complex interconnection between these types of attentional bias has not yet been tested. This study aimed to investigate the association between attentional bias to pain words and attentional bias to the location of pain, as well as the moderating role of pain-related interpretation bias in this association. Fifty-four healthy individuals performed a visual probe task with pain-related and neutral words, during which eye movements were tracked. In a subset of trials, participants were presented with a cold pain stimulus on one hand. Pain-related interpretation and memory biases were also assessed. Attentional bias to pain words and attentional bias to the pain location were not significantly correlated, although the association was significantly moderated by interpretation bias. A combination of pain-related interpretation bias and attentional bias to painful sensations was associated with avoidance of pain words. In addition, first fixation durations on pain words were longer when the pain word and cold pain stimulus were presented on the same side of the body, as compared to on opposite sides. This indicates that congruency between the locations of pain and pain-related information may strengthen attentional bias. Overall, these findings indicate that cognitive biases to pain-related information interact with cognitive biases to somatosensory information. The implications of these findings for attentional bias modification interventions are discussed.

Automatic Coding of Facial Expressions of Pain: Are We There Yet?

Introduction

The experience of pain is regularly accompanied by facial expressions. The gold standard for analyzing these facial expressions is the Facial Action Coding System (FACS), which provides so-called action units (AUs) as parametrical indicators of facial muscular activity. Particular combinations of AUs have appeared to be pain-indicative. The manual coding of AUs is, however, too time- and labor-intensive in clinical practice. New developments in automatic facial expression analysis have promised to enable automatic detection of AUs, which might be used for pain detection.

Objective

Our aim is to compare manual with automatic AU coding of facial expressions of pain.

Methods

FaceReader7 was used for automatic AU detection. We compared the performance of FaceReader7 using videos of 40 participants (20 younger with a mean age of 25.7 years and 20 older with a mean age of 52.1 years) undergoing experimentally induced heat pain to manually coded AUs as gold standard labeling. Percentages of correctly and falsely classified AUs were calculated, and we computed as indicators of congruency, “sensitivity/recall,” “precision,” and “overall agreement (F1).”

Results

The automatic coding of AUs only showed poor to moderate outcomes regarding sensitivity/recall, precision, and F1. The congruency was better for younger compared to older faces and was better for pain-indicative AUs compared to other AUs.

Conclusion

At the moment, automatic analyses of genuine facial expressions of pain may qualify at best as semiautomatic systems, which require further validation by human observers before they can be used to validly assess facial expressions of pain.

The disruptive effects of pain on the early allocation of attentional resources: An attentional blink study

BACKGROUND

Recent evidence suggests that pain dampens attentional processes. However, much of this work has been based on higher-order attentional tasks that involve only spatial attention. Other aspects of the process through which pain engages and holds attention are relatively understudied, in particular, temporal attention. The present set of studies explored how naturally occurring pain (i.e. acute headache) and pain-valenced stimuli affect the ability to recall the second of two targets presented in rapid succession.

METHODS

Across both experiments participants were required to indicate the presence of a predefined probe (T2) and, in the dual task, identify a target (T1). The probe (T2) was placed in three different temporal proximities (ranging from 70 to 1000 ms) following presentation of the target (T1). In Experiment 1, 36 participants completed a task that comprised a rapid stream of letters. Experiment 2 manipulated the threat value, and the complexity, of the stimuli by replacing letters with words. In the dual task condition, T1 was a word from one of four valence categories (neutral, positive, negative, pain).

RESULTS

Being in acute pain reduced the accuracy of identification. This reduction in performance occurred regardless of the temporal positioning of the probe, consistent with previous work that suggests pain has an overall dampening effect. Furthermore, when the valence category of the word was pain-related, T2 accuracy performance was negatively affected.

CONCLUSION

These findings add to the previous evidence that pain has a general dampening effect on attention and that pain-related stimuli are difficult to disengage from.

SIGNIFICANCE

Pain captures attention to allow cognate resources to be directed appropriately in response. However, the temporal effects of this attentional capture are poorly understood. Findings indicate that acute headache pain has a negative impact on participants' performance when identifying the second of two targets presented in close temporal proximity, and that pain-valenced stimuli exacerbate this effect. These findings demonstrate how pain affects early attention and highlights the potential role of disengagement, rather than orientation, of attention in the pain experience.

Attentional Biases Towards Body Expressions of Pain in Men and Women

This study investigated whether there are gender differences in attention to bodily expressions of pain and core emotions. Three experiments are reported using the attentional dot probe task. Images of men and women displaying bodily expressions, including pain, were presented. The task was used to determine whether participants' attention was drawn towards or away from target expressions. Inconsistent evidence was found for an attentional bias towards body expressions, including pain. While biases were affected by gender, patterns varied across the Experiments. Experiment 1, which had a presentation duration of 500 ms, found a relative bias towards the location of male body expressions compared to female expressions. Experiments 2 and 3 varied stimulus exposure times by including both shorter and longer duration conditions (e.g., 100 vs. 500 vs. 1250 ms). In these experiments, a bias towards pain was confirmed. Gender differences were also found, especially in the longer presentation conditions. Expressive body postures captured the attention of women for longer compared to men. These results are discussed in light of their implications for why there are gender differences in attention to pain, and what impact this has on pain behaviour. PERSPECTIVE: We show that men and women might differ in how they direct their attention towards bodily expressions, including pain. These results have relevance to understanding how carers might attend to the pain of others, as well as highlighting the wider role that social-contextual factors have in pain.

The gender context of pain

Pain is a major source of global suffering, with women bearing the greatest burden. Alongside biology, psychological and social factors, including gender, help explain these differences. However, there has been no direct attempt to develop a unified social psychological model of men and women's pain. By drawing on approaches to both gender and pain, a gender context model of pain is presented. It proposes that pain is partly influenced by the gender context in which it occurs, which operates at both individual and interpersonal levels. The model is used to structure an appraisal of the existing evidence around gender and pain, and explore whether the model helps explain why such variation occurs. It is argued that despite evidence for an association between gender and pain, there are empirical gaps that need to be addressed. Implications and directions for future investigations into sex, gender and pain are considered.

Gender differences in attention to pain body postures in a social context: a novel use of the bodies in the crowd task

Pain signals the presence of potential harm, captures attention, and can inhibit performance on concurrent tasks. What is less well known, however, is whether such attentional capture also occurs in a wider social context, such as when observing people in pain. To explore this possibility, we adopted a novel social-cue detection methodology: the bodies-in-the-crowd task. Two experiments are reported that consider whether nonverbal cues of pain, happiness, and anger as expressed through body postures would capture and hold attention. Both experiments recruited 40 (20 male and 20 female) pain-free individuals. Overall, results show that pain postures do not capture attention any more than happiness or anger postures, but disengagement from pain postures was significantly slower across both studies. Gender differences were also found, and were more likely to be found when crowds comprised both men and women. Male pain postures were more likely to capture attention. However, female observers had faster target detection speed, and were quicker to disengage from distractors. They also showed slower disengagement from female expressions overall. Male observers showed no variation based on target or distractor gender. Implications and potential directions for future research are discussed.

Attentional control moderates the relationship between pain catastrophizing and selective attention to pain faces on the antisaccade task

Cognitive models of chronic pain emphasize the critical role of pain catastrophizing in attentional bias to pain-related stimuli. The aim of this study was (a) to investigate the relationship between pain catastrophizing and the ability to inhibit selective attention to pain-related faces (attentional bias); and (b) to determine whether attentional control moderated this relationship. One hundred and ten pain-free participants completed the anti-saccade task with dynamic facial expressions, specifically painful, angry, happy, and neutral facial expressions and questionnaires including a measure of pain catastrophizing. As predicted, participants with high pain catastrophizing had significantly higher error rates for antisaccade trials with pain faces relative to other facial expressions, indicating a difficulty disinhibiting attention towards painful faces. In moderation analyses, data showed that attentional control moderated the relationship between attentional bias to pain faces and pain catastrophizing. Post-hoc analyses demonstrated that it was shifting attention (not focusing) that accounted for this effect. Only for those with high self-reported ability to shift attention was there a significant relationship between catastrophizing and attentional bias to pain. These findings confirm that attentional control is necessary for an association between attentional bias and catastrophizing to be observed, which may explain the lack of relationships between attentional bias and individual characteristics, such as catastrophizing, in prior research.

Facial Features Underlying the Decoding of Pain Expressions

Previous research has revealed that the face is a finely tuned medium for pain communication. Studies assessing the decoding of facial expressions of pain have revealed an interesting discrepancy, namely that, despite eyes narrowing being the most frequent facial expression accompanying pain, individuals mostly rely on brow lowering and nose wrinkling/upper lip raising to evaluate pain. The present study verifies if this discrepancy may reflect an interaction between the features coding pain expressions and the features used by observers and stored in their mental representations. Experiment 1 shows that more weight is allocated to the brow lowering and nose wrinkling/upper lip raising, supporting the idea that these features are allocated more importance when mental representations of pain expressions are stored in memory. These 2 features have been associated with negative valence and with the affective dimension of pain, whereas the eyes narrowing feature has been associated more closely with the sensory dimension of pain. However, experiment 2 shows that these 2 features remain more salient than eyes narrowing, even when attention is specifically directed toward the sensory dimension of pain. Together, these results suggest that the features most saliently coded in the mental representation of facial expressions of pain may reflect a bias toward allocating more weight to the affective information encoded in the face. PERSPECTIVE: This work reveals the relative importance of 3 facial features representing the core of pain expressions during pain decoding. The results show that 2 features are over-represented; this finding may potentially be linked with the estimation biases occurring when clinicians and lay persons evaluate pain based on facial appearance.