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Hansson LS, Lasselin J, Tognetti A, Axelsson J, Olsson MJ, Sundelin T, Lekander M. The walking sick: Perception of experimental sickness from biological motion. Brain Behav Immun 2023; 113:319-327. [PMID: 37517742 DOI: 10.1016/j.bbi.2023.07.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 06/09/2023] [Accepted: 07/25/2023] [Indexed: 08/01/2023] Open
Abstract
Identification of sick conspecifics allows for avoidance of infectious threats, and is therefore an important behavioral defense against diseases. Here, we investigated if humans can identify sick individuals solely from biological motion and posture (using point-light displays). Additionally, we sought to determine which movements and sickness parameters would predict such detection. We collected video clips and derived point-light displays (one stride presented in a loop) of sick walkers (injected with lipopolysaccharide at 2.0 ng/kg body weight) and the same walkers when healthy (injected with saline). We then presented these displays to two groups, one group classified each walker as sick or healthy (study 1, n = 106), and the other group scored the walkers' health on a visual analogue scale (study 2, n = 106). The raters were able to identify sick individuals above chance, and rated sick walkers as having worse health, both from observing video clips and point-light displays. Furthermore, both sickness detection and worse apparent health were predicted by inflammation-induced increase in rigidity and slower walking, but not other cues. Altogether, these findings indicate that biological motion can serve as a sickness cue, possibly allowing humans to identify sick conspecifics from a distance, and thereby allowing for disease avoidance.
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Affiliation(s)
- L S Hansson
- Stress Research Institute, Department of Psychology, Stockholm University, Stockholm, Sweden; Division of Psychology, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden; Osher Center for Integrative Health, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - J Lasselin
- Stress Research Institute, Department of Psychology, Stockholm University, Stockholm, Sweden; Division of Psychology, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden; Osher Center for Integrative Health, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.
| | - A Tognetti
- Division of Psychology, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - J Axelsson
- Stress Research Institute, Department of Psychology, Stockholm University, Stockholm, Sweden; Division of Psychology, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - M J Olsson
- Division of Psychology, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - T Sundelin
- Stress Research Institute, Department of Psychology, Stockholm University, Stockholm, Sweden; Division of Psychology, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - M Lekander
- Stress Research Institute, Department of Psychology, Stockholm University, Stockholm, Sweden; Division of Psychology, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden; Osher Center for Integrative Health, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
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Schwambergová D, Pátková Ž, Třebická Fialová J, Třebický V, Stella D, Havlíček J. Immunoactivation Affects Perceived Body Odor and Facial but Not Vocal Attractiveness. EVOLUTIONARY PSYCHOLOGY 2023; 21:14747049231218010. [PMID: 38087426 PMCID: PMC10722934 DOI: 10.1177/14747049231218010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Accepted: 11/16/2023] [Indexed: 12/18/2023] Open
Abstract
Several previous studies have shown that in mammals, the health status of conspecifics can be assessed based on perceptual cues. Olfactory, visual, or acoustic cues may lead to avoidant behavior, thus reducing the risk of contagion by close contact with infected individuals. We tested whether immune system activation after immunization leads to perceptible changes in body odor and facial and vocal attractiveness in humans. We have experimentally activated the immune system of male participants using vaccination against hepatitis A/B and meningococcus. Their body odor, facial photographs, and vocal recordings were collected before and 14 days after vaccination. Subsequently, the body odor samples, facial photographs, and vocal recordings were assessed by female raters for their attractiveness and healthiness. We have also measured skin coloration (from facial photographs and in vivo using a spectrophotometer), vocal parameters, and C-reactive protein (CRP) levels as a marker of inflammation. We found an increase in perceived body odor attractiveness, a decrease in facial attractiveness and healthiness, and no change in vocal attractiveness 14 days after vaccination compared to the prevaccination condition. Moreover, there was no change in facial coloration or vocal parameters between the prevaccination and postvaccination conditions. Prevaccination CRP levels were negatively associated with body odor and facial attractiveness and positively associated with body odor intensity. Overall, our results suggest that perceived body odor as well as facial but not vocal attractiveness may provide cues to activation of the immune response and that each modality may carry specific information about the individual's condition.
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Affiliation(s)
- Dagmar Schwambergová
- Department of Zoology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Žaneta Pátková
- Department of Philosophy and History of Sciences, Faculty of Science, Charles University, Prague, Czech Republic
| | | | - Vít Třebický
- Faculty of Physical Education and Sport, Charles University, Prague, Czech Republic
| | - David Stella
- Department of the Human Dimensions of Global Change, Global Change Research Institute CAS, Brno, Czech Republic
| | - Jan Havlíček
- Department of Zoology, Faculty of Science, Charles University, Prague, Czech Republic
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Schwambergová D, Kaňková Š, Třebická Fialová J, Hlaváčová J, Havlíček J. Pandemic elevates sensitivity to moral disgust but not pathogen disgust. Sci Rep 2023; 13:8206. [PMID: 37217674 DOI: 10.1038/s41598-023-35375-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 05/17/2023] [Indexed: 05/24/2023] Open
Abstract
The behavioral immune system, with disgust as its motivational part, serves as the first line of defense in organisms' protection against pathogens. Laboratory studies indicate that disgust sensitivity adaptively adjusts to simulated environmental threat, but whether disgust levels similarly change in response to real-life threats, such as a pandemic, remains largely unknown. In a preregistered within-subject study, we tested whether the threat posed by the Covid-19 pandemic would lead to increased perceived disgust. The perception of threat was induced by testing during two phases of the Covid-19 pandemic (periods of high vs. low pathogen threat). We found heightened levels of moral disgust during a "wave" of the pandemic, but the effect was not observed in the domain of pathogen or sexual disgust. Moreover, the age of respondents and levels of trait anxiety were positively associated with pathogen and moral disgust, suggesting that variation in disgust sensitivity may be based chiefly on stable characteristics.
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Affiliation(s)
- Dagmar Schwambergová
- Department of Zoology, Faculty of Science, Charles University, Viničná 7, 128 44, Prague 2, Czech Republic.
- National Institute of Mental Health, Topolová 748, 250 67, Klecany, Czech Republic.
| | - Šárka Kaňková
- Department of Philosophy and History of Science, Faculty of Science, Charles University, Viničná 7, 128 44, Prague 2, Czech Republic
| | - Jitka Třebická Fialová
- Department of Zoology, Faculty of Science, Charles University, Viničná 7, 128 44, Prague 2, Czech Republic
| | - Jana Hlaváčová
- Department of Philosophy and History of Science, Faculty of Science, Charles University, Viničná 7, 128 44, Prague 2, Czech Republic
| | - Jan Havlíček
- Department of Zoology, Faculty of Science, Charles University, Viničná 7, 128 44, Prague 2, Czech Republic
- National Institute of Mental Health, Topolová 748, 250 67, Klecany, Czech Republic
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Behavioral and physiological sensitivity to natural sick faces. Brain Behav Immun 2023; 110:195-211. [PMID: 36893923 DOI: 10.1016/j.bbi.2023.03.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 03/03/2023] [Accepted: 03/03/2023] [Indexed: 03/11/2023] Open
Abstract
The capacity to rapidly detect and avoid sick people may be adaptive. Given that faces are reliably available, as well as rapidly detected and processed, they may provide health information that influences social interaction. Prior studies used faces that were manipulated to appear sick (e.g., editing photos, inducing inflammatory response); however, responses to naturally sick faces remain largely unexplored. We tested whether adults detected subtle cues of genuine, acute, potentially contagious illness in face photos compared to the same individuals when healthy. We tracked illness symptoms and severity with the Sickness Questionnaire and Common Cold Questionnaire. We also checked that sick and healthy photos were matched on low-level features. We found that participants (N = 109) rated sick faces, compared to healthy faces, as sicker, more dangerous, and eliciting more unpleasant feelings. Participants (N = 90) rated sick faces as more likely to be avoided, more tired, and more negative in expression than healthy faces. In a passive-viewing eye-tracking task, participants (N = 50) looked longer at healthy than sick faces, especially the eye region, suggesting people may be more drawn to healthy conspecifics. When making approach-avoidance decisions, participants (N = 112) had greater pupil dilation to sick than healthy faces, and more pupil dilation was associated with greater avoidance, suggesting elevated arousal to threat. Across all experiments, participants' behaviors correlated with the degree of sickness, as reported by the face donors, suggesting a nuanced, fine-tuned sensitivity. Together, these findings suggest that humans may detect subtle threats of contagion from sick faces, which may facilitate illness avoidance. By better understanding how humans naturally avoid illness in conspecifics, we may identify what information is used and ultimately improve public health.
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Tybur JM, Fan L, Jones BC, Holzleitner IJ, Lee AJ, DeBruine LM. Re-evaluating the relationship between pathogen avoidance and preferences for facial symmetry and sexual dimorphism: A registered report. EVOL HUM BEHAV 2022. [DOI: 10.1016/j.evolhumbehav.2022.01.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Shattuck EC. Networks, cultures, and institutions: Toward a social immunology. Brain Behav Immun Health 2021; 18:100367. [PMID: 34761241 PMCID: PMC8566934 DOI: 10.1016/j.bbih.2021.100367] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Revised: 10/08/2021] [Accepted: 10/08/2021] [Indexed: 12/26/2022] Open
Abstract
This paper calls for increased attention to the ways in which immune function – including its behavioral aspects – are responsive to social contexts at multiple levels. Psychoneuroimmunology has demonstrated that the quantity and quality of social connections can affect immune responses, while newer research is finding that sickness temporarily affects these same social networks and that some aspects of culture can potentially “get under the skin” to affect inflammatory responses. Social immunology, the research framework proposed here, unifies these findings and also considers the effects of structural factors – that is, a society's economic, political, and environmental landscape – on exposure to pathogens and subsequent immune responses. As the COVID-19 pandemic has highlighted, a holistic understanding of the effects of social contexts on the patterning of morbidity and mortality is critically important. Social immunology provides such a framework and can highlight important risk factors related to impaired immune function.
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Affiliation(s)
- Eric C Shattuck
- Institute for Health Disparities Research, University of Texas at San Antonio, San Antonio, TX, USA.,Department of Public Health, University of Texas at San Antonio, San Antonio, TX, USA
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