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. 2021 Jul 28;288(1955):20210376.
doi: 10.1098/rspb.2021.0376. Epub 2021 Jul 28.

The skin crawls, the stomach turns: ectoparasites and pathogens elicit distinct defensive responses in humans

Tom R Kupfer  1   2 , Daniel M T Fessler  3   4   5 , Bozhi Wu  3 , Tiffany Hwang  3   6 , Adam Maxwell Sparks  3   4   7 , Sonia Alas  3 , Theodore Samore  3   4 , Vedika Lal  2 , Tanvi P Sakhamuru  3   8 , Colin Holbrook  9
Affiliations

The skin crawls, the stomach turns: ectoparasites and pathogens elicit distinct defensive responses in humans

Tom R Kupfer et al. Proc Biol Sci. .

Abstract

Disgust has long been viewed as a primary motivator of defensive responses to threats posed by both microscopic pathogens and macroscopic ectoparasites. Although disgust can defend effectively against pathogens encountered through ingestion or incidental contact, it offers limited protection against ectoparasites, which actively pursue a host and attach to its surface. Humans might, therefore, possess a distinct ectoparasite defence system-including cutaneous sensory mechanisms and grooming behaviours-functionally suited to guard the body's surface. In two US studies and one in China, participants (N = 1079) viewed a range of ectoparasite- and pathogen-relevant video stimuli and reported their feelings, physiological sensations, and behavioural motivations. Participants reported more surface-guarding responses towards ectoparasite stimuli than towards pathogen stimuli, and more ingestion/contamination-reduction responses towards pathogen stimuli than towards ectoparasite stimuli. Like other species, humans appear to possess evolved psychobehavioural ectoparasite defence mechanisms that are distinct from pathogen defence mechanisms.

Keywords: behavioural immune system; disgust; ectoparasites; grooming; pathogens.

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Figures

Figure 1.
Figure 1.
Participants' oral-gastric (OG) and skin-surface (SS) responses when viewing pathogen and ectoparasite video stimuli in Studies 1, 2, and 3. Response intensity ranges from 0, ‘not at all’ to 6, ‘very strongly’. Raw data are jittered. Beans represent smoothed density of raw data. Boxes and lines represent 95% confidence intervals and means, respectively. (Online version in colour.)
See this image and copyright information in PMC

References

    1. Curtis V, Biran A. 2001. Dirt, disgust, and disease: is hygiene in our genes? Perspect. Biol. Med. 44, 17-31. (10.1353/pbm.2001.0001) - DOI - PubMed
    1. Davey GC. 2011. Disgust: the disease-avoidance emotion and its dysfunctions. Phil. Trans. R. Soc. B 366, 3453-3465. (10.1098/rstb.2011.0039) - DOI - PMC - PubMed
    1. Oaten M, Stevenson RJ, Case TI. 2009. Disgust as a disease-avoidance mechanism. Psychol. Bull. 135, 303. (10.1037/a0014823) - DOI - PubMed
    1. Curtis V, Aunger R, Rabie T. 2004. Evidence that disgust evolved to protect from risk of disease. Proc. R. Soc. B 271, 131-133. (10.1098/rsbl.2003.0144) - DOI - PMC - PubMed
    1. Royzman EB, Leeman RF, Sabini J. 2008. ‘You make me sick’: moral dyspepsia as a reaction to third-party sibling incest. Motiv. Emot. 32, 100-108. (10.1007/s11031-008-9089-x) - DOI

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