Background & Aims

The presence of conspecifics impacts pain perception and possibly induces a placebo hypoalgesia (Bagnis et al., 2023; Krahè et al., 2013; Mattarozzi et al., 2021). As powerful social stimuli, human faces swiftly convey inferences on social traits such as familiarity, trustworthiness, and dominance, shaping people’s dispositions and social outcomes (Todorov et al., 2015). This study bridges these two lines of research – social modulation of pain and facial-appearance-based inferences – aiming to: i) define the mental and prototypical representation of a ‘good doctor’ through a model predicting attributes from face images; ii) examine whether this prototypical ‘good doctor’ representation modulates the subjective pain experience by reducing the sense of threat through inferences of familiarity. This effect is expected to be influenced by individual factors, including resting Heart Rate Variability (HRV) and genetic polymorphisms related to opioid, dopamine, and oxytocin systems.

Methods

For the first aim, 379 participants completed a face rating task reporting, on a VAS from 0 (not at all) to 100 (extremely), how much the stimulus represented a ‘good doctor’ based on their first impression. For the second aim, 220 participants will be recruited to detect an effect size of .25 (1 – ? = 0.95, ? =0.05) (Faul et al., 2007). This sample size is in line with the literature to achieve reliable results with DNA analyses (Colagiuri et al., 2015). After collecting saliva sample and recording resting HRV, participants perform a pain task, viewing faces corresponding to one’s mental representation of a ‘good doctor’ (‘high good doctor’ faces) and faces distant from this representation (‘low good doctor’ faces), while receiving electric impulses on their non- dominant forearm. Pain intensity and unpleasantness on a 0-100 VAS are collected. The genotype of 11 polymorphisms previously associated with placebo hypoalgesia (Colloca et al., 2019) were evaluated by Sanger sequencing.

Results

With respect to the first aim, data were analyzed by considering the physical and psychological dimensions included in the model described in Peterson et al., 2022, and therefore by applying the same algorithms. Split-half coefficient (r=0.79) showed that participant ratings reliably reflected the degree in which the displayed face represented, in their opinion, a ‘good doctor’. The ratings were used to generate a new model dimension, namely the ‘good doctor’ dimension, which allows the manipulation of images of faces that, according to the sample considered, to appear more or less alike to a ‘good doctor’. This dimension was positively correlated with existing model dimensions such as ‘familiar’, ‘smart’, ‘electable’ and ‘godly’ (r=0.75). Regarding the second aim, so far (as of 30 January 2024), 130 participants have completed the experimental procedure. Results will hence be available at the time of the IASP Congress.

Conclusions

A novel aspect of our experimental manipulation is that we have created a model that visualizes the prototypical representation of a ‘good doctor’. Data analysis for the first aim revealed positive relationships between perceived psychological traits such as ‘familiar’, ‘smart’, ‘electable’ and ‘godly’ with the ‘good doctor’ dimension. In light of previous studies showing that patient inferences from healthcare providers facial appearance have an impact on pain perception (Mattarozzi et al., 2021; Anderson et al., 2023), we would test whether this representation modulates the subjective pain experience, and whether individual factors such as resting state HRV and genetic markers influence this modulation. The results may open avenues for further investigation and applications in healthcare, where the interpersonal aspects of medical care play a crucial role.

References

Anderson, S. R., Gianola, M., Medina, N. A., Perry, J. M., Wager, T. D., & Losin, E. A. R. (2023). Doctor trustworthiness influences pain and its neural correlates in virtual medical interactions.?Cerebral Cortex,?33(7), 3421-3436.

Bagnis, A., Todorov, A., Altizio, I., Colonnello, V., Fanti, S., Russo, P. M., & Mattarozzi, K. (2023). Familiarity from facial appearance leads to hypoalgesia.?The Journal of Pain. https://doi.org/10.1016/j.jpain.2023.06.012

Colagiuri, B., Schenk, L. A., Kessler, M. D., Dorsey, S. G., & Colloca, L. (2015). The placebo effect: From concepts to genes.?Neuroscience,?307, 171–190. https://doi.org/10.1016/j.neuroscience.2015.08.017

Colloca, L., Wang, Y., Martinez, P. E., Chang, Y. C., Ryan, K. A., Hodgkinson, C., Goldman, D., & Dorsey, S. G. (2019). OPRM1 rs1799971, COMT rs4680, and FAAH rs324420 genes interact with placebo procedures to induce hypoalgesia. Pain, 160(8), 1824–1834. https://doi.org/10.1097/j.pain.0000000000001578

Faul, F., Erdfelder, E., Lang, A. G., & Buchner, A. (2007). G*Power 3: a flexible statistical power analysis program for the social, behavioral, and biomedical sciences.?Behavior research methods,?39(2), 175–191. https://doi.org/10.3758/bf03193146

Krahé, C., Springer, A., Weinman, J. A., & Fotopoulou, A. (2013). The social modulation of pain: others as predictive signals of salience–a systematic review.?Frontiers in human neuroscience,?7, 386. https://doi.org/10.3389/fnhum.2013.00386

Mattarozzi, K., Caponera, E., Russo, P. M., Colonnello, V., Bassetti, M., Farolfi, E., & Todorov, A. (2021). Pain and satisfaction: healthcare providers’ facial appearance matters.?Psychological research,?85, 1706-1712. https://doi.org/10.1007/s00426-020-01330-3

Peterson, J. C., Uddenberg, S., Griffiths, T. L., Todorov, A., Suchow, J. W. (2022). Deep models of superficial face judgments.?Proceedings of the National Academy of Sciences,?119(17), https://doi.org/10.1073/pnas.2115228119

Todorov, A., Olivola, C. Y., Dotsch, R., Mende-Siedlecki, P. (2015). Social attributions from faces: Determinants, consequences, accuracy, and functional significance.?Annual review of psychology,?66, 519-545. https://doi.org/10.1146/annurev-psych-113011-143831

Presenting Author

Ilenia Ceccarelli

Poster Authors

Ilenia Ceccarelli

MSc

University of Bologna - Department of Medical and Surgical Sciences

Lead Author

E-mail

Topics

  • Mechanisms: Psychosocial and Biopsychosocial