Disgust Flashcards
Why is disgust of interest to moral psychology ?
- unique to humans—not reliably observed in other species
- has entirely non-social evolutionary origins (in contrast with Frans de Waal’s analysis)
- has strong bodily response
Explain the evolution of pathogen disgust
- we can’t see pathogens and parasites, they’re hard to avoid
- we evolved different mechanisms for avoiding them
- infectious microorganisms can’t travel long, must invade through direct contact of certain body parts
- areas of interest: skin, mouth, anus, genitals
The one bodily fluid that doesn’t evoke disgust
Tears!
Neophobia
Humans’ fear of taking unknown things into their bodies
Four key features of pathogen disgust
Behaviour: avoidance
Physiological: nausea
Expression: disgust face
feeling (aka. Qualia): revulsion
What is disgust face?
When someone wrinkles their nose and retracts their upper lip. This reduces air flow and exposure
First “magical law of contagion”
Law 1: once in contact, always in contact: when an offensive (or revered) person or animal touches something, some essence or residue is transmitted
Eg. Wanting to wear Grimes sweater, not wanting to wear Hitler’s sweater. Also people don’t want to wear clothes of disabled people :’(
This is regardless of laundering and sterilization.
Second “magical law of contagion”
Law 2: that if things are superficially similar then they are similar in a deep sense as well; i.e., appearance is reality
Eg. Fudge that looks like dog turd
The link between morality & disgust…
Is BIDIRECTIONAL—things that are viewed as morally wrong are seen as disgusting; things that are disgusting are morally wrong.
Across cultures and languages, people feel similarly about their non-preferred politicians and feces.
evidence showing the ~bidirectional~ link between disgust and morality
- children as young as 6 describing situations of unfairness and moral transgression “disgusting”
- fMRI: comparable neural activation for disgust and unfairness!
- facial electromyography: facial muscles involved in experience of disgust also involved in moral transgression
But why does this link exist? Scientists don’t agree on one explanation
What is Tybur et al.’s explanation for the disgust > morality link?
- humans live in groups, governed by moral rules
- rules enforced by moralistic punishment of violators
- people support/reject rules based on its implications for their own fitness (eg. Adultery)
- people have strong pathogen disgust responses, adaptive to survival and reproductive success
- the more a rule evokes disgust, the more likely one is to support it, because it is more likely to be evolutionarily advantageous.
- disgust reactions also informs us which actions to avoid so as to avoid social condemnation.
Evidence for this:
- people exposed to disgusting smell judge immoral acts more harshly than control participants not exposed to the smell
- people exposed to a disgusting taste, judge immoral acts more harshly
What is Tybur et al.’s explanation for the morality > disgust link?
- people report moral violations that have no relation to pathogen contamination as disgusting
- enforcing punishment to rule violators can be costly
==> coordinate condemnation: condemn people through displays of disgust, eg. Giving them a dirty look - People can use disgust displays to communicate a reliable cue that others view the rule violation as disgusting..
When does disgust develop?
In North American children, ages 4-8
Disgust development & evolution:
- infants don’t display disgust to things that most adults and children do, ie. feces and poop
- they do dislike bitter foods, but that’s about it
- in ancestral times, children were breastfed to much older ages
- breast milk was a pathogen-screened form of nutrients
- humans must learn pathogen avoidance from their society!
- probably because pathogens & culture vary by geographic region
- breastfeeding gives child time to learn
- not all cultures have disgust: study of 50 feral humans found no expression of disgust
Developmental mechanisms of disgust (like for children)
- reactions of others e.g., if you don’t flush feces and you decide to play with it, adult will be horrified
- generalization: if feces are disgusting, other bodily products must be, too
- evaluative conditioning: pairing of unconditioned stimulus (diaper changers face), with conditioned stimulus (diaper changing)
