The Psychology of Disgust

[Eris]

What's more disgusting than biting into an apple and finding a worm inside?

http://www.sas.upenn.edu/sasalum/newslt ... rozin.html

[Will]

Biting into an apple and finding half a worm.

Interesting article!

[tacoma_kyle]

Meth-head mouths... ewww....!!!

Last year I worked at Subway (cut me some slack---I'm goin to school! -----I'm a pharmacy tech now) for a month.

Let me just say S. Oregonia has a rep for meth. Medford nearby has a nickname of Methford. Klamath is no different.

Point? I would see some absolutely disgusting mouths on a daily basis. Black, raunchy gums and rotton teeth....eeewwww.....

[Eris]

Pretty sick what people do to themselves, isn't it?

Kyle, is it snowing down there like it is up here in Portland?

[SteveS]

Yeah, a worm in an apple is gross, but I guess it could always be worse!  :wink:  

Reminds me, when I was a kid, I was riding my bike down a big hill and accidentally swallowed one of those yellow moths that are all powdery - the bugger flew right into me!  It was nasty --- I was scraping yellow moth-powder off my tongue    

I figured I'd just look at it as a protein supplement.  It went down the hatch, too late to worry about it.....

[myleviathan]

Anybody ever catch Strange Foods with Andrew Zimmern? I always feel determined to eat something disgusting after watching that show. He makes eating worms look like a lot of fun. One thing I would't eat that he did in Russia - lamprey. That's just wrong. That's disgusting in absolutely every sense of the word. [attachment=2:1m85z3gm]lamprey.jpg[/attachment:1m85z3gm][attachment=1:1m85z3gm]lampreyillustration.png[/attachment:1m85z3gm]

[Squid]

Disgust is interesting.  I haven't looked much into the more social psych aspect of it, but I have delved a bit into the biopsych side of it.  Here's a short little tidbit from my neurobiology class from this past semester I wrote on the subject:

Disgust is thought to have arisen as an advantage to protect our ancestors from noxious agents such as carcasses, bodily fluids, stagnant water and so forth â€" that which may be bathed in bacteria or other microorganisms or substances that can cause illness or death (Fessler, 2005).

Wicker et al. (2003) performed an experiment to look into the neural areas governing our feeling of disgust.  They had 14 healthy male subjects view videos of people smelling something in a glass which were disgusting, pleasant or neutral.  They then had participants inhale odorants through a mask of which some were disgusting and some were pleasant.  To assess the brain function during these tasks, fMRI was utilized.  The anatomical areas implicated were the left anterior insula and the right anterior cingulate cortex.  The insula, specifically the anterior area is involved in autonomic processes involving items such as olfaction and visceral sensations.  Electrical stimulation of the area has found to induce nausea in patients.  The anterior cingulate cortex has been implicated in the processing of painful stimuli as well as aversive olfactory responses.  This research not only showed anatomical structures involved in disgust but also that those structures are activated whether we are actually smelling something disgusting or watching someone else smell something disgusting.

Some research has reported that those suffering from Huntington’s disease have an impairment to recognize disgust in others.  Not only is this deficit seen in those with apparent Huntington’s but also those categorized as pre-symptomatic.  Hennenlotter et al. (2004) took this information and performed a study on nine pre-symptomatic individuals.  They compared this group to a control group of nine healthy adults.  The assessment of brain function was made utilizing fMRI and the participants viewed faces which displayed expressions such as disgust or neutral expressions.  The healthy participants showed increased activity in the dorsal anterior insula and left putamen which was the expect outcome based upon other similar studies assessing the functional aspects of disgust.  The Huntington’s group, however, showed decreased activiation in the dorsal anterior insula.  The reason for this is thought to be due to the changes in this and other areas from Huntington’s. It is thought to disrupt the basal gangliaâ€"thalamocortical loops and is important in that it seems to only effect those expressions for disgust. Similar deficits are also seen in those suffering from other neurological conditions such as Parkinson’s.  

As was alluded to by previously described research, areas involved in disgust were not just simple visceral responses but also areas involved in what is thought of as social cognition.  Harris and Fiske (2006) examined the social aspect of disgust in their research as it relates to stereotypes and racial prejudice.  They examined 22 undergraduate students by having them view images of social groups and objects.  To assess their brain function, fMRI was utilized.  In relation to feelings of disgust, they found that the participants had heightened activity in their amygdala and insula.  The social aspect was apparent in viewing the pictures of social groups which correlated to activation of the medial prefrontal cortex.  This social disgust shows that it retains aspects of the primal, evolutionary disgust as well as a larger conceptual framework to which we utilize to make value judgements about other individuals and groups.

Disgust quite possibly arose as an evolutionary advantage to keep our ancestors from harmful agents but over time has evolved into a much larger role in our lives as we have become more and more of a social animal.
   


References

Fessler, D., Eng, S. & Navarrete, C. (2005). Elevated disgust sensitivity in the first trimester of pregnancy: Evidence supporting the compensatory prophylaxis hypothesis. Evolution and Human Behavior, 26, 344-351.

Harris, L. & Fiske, S. (2006). Dehumanizing the lowest of the low. Psychological Science, 17, 847-853.

Hennenlotter, A., Schroeder, U., Erhard, P., Haslinger, B., Stahl, R., Weindl, A. et al. (2004). Neural correlates associated with impaired disgust processing in pre-symptomatic Huntington’s disease. Brain, 127, 1446-1453

Wicker, B., Keysers, C., Plailly, J., Royet, J., Gallese, V. & Rizzolatti, G. (2003). Both of us disgusted in my insula: The common neural basis of seeing and feeling disgust.  Neuron, 40, 655-664.

[karadan]

My mum used to work in a hospital. I used to help put up decorations over Christmas on her ward. There was an old guy brought in who'd sadly been alone and unable to care for himself for some time. You could tell he was in a lot of pain when wheeled in and there was a strange smell about his person. The first thing the nurses did was try to get him in some hospital whites. This was until they took his shoes off. Seemingly, he'd not taken off his shoes - including socks - for some years. The skin on his feet had actually grown over his socks!! My mum had the unpleasant job of removing the top layer of skin, then the socks (which peeled off in strips). The smell was something i'll never forget. It filled the entire ward. All windows had to be opened. Of course, i wasn't watching this ghastly process, i was busy putting up crimbo decorations. I could, however, hear the moans and the occasional retching noise from my mother and the nurses attending. It was only some years later that my mother told me the whole story.

I wasn't disgusted by the man, or particularly the smell, but that someone could be left in such a sorry state with no help.... That disgusted me.

[myleviathan]

Squid wrote:

The Huntington’s group, however, showed decreased activiation in the dorsal anterior insula.

Does 'dorsal anterior insula' refer to the dorsal and anterior sections of the insula or is there an anatomical feature of the insula known as the dorsal anterior insula? I was just wondering because I was taking an anatomy class and we just finished the structures of the brain. I love seeing a practical psychological application for learning anatomy.

Fascinating stuff by the way. It's interesting to trace the lineage of disgust from it's early role in preventing infection to it's later development to forms of social disgust that would include racism/genocide, rape, political discord, etc.

[Squid]

Squid wrote:

The Huntington’s group, however, showed decreased activiation in the dorsal anterior insula.

Does 'dorsal anterior insula' refer to the dorsal and anterior sections of the insula <snip>

Yes.