He describes the emotion of disgust as a universal response, i.e. it is similarly present throughout many different culture's, and so this is good evidence that it is hardwired into our biology.
"people seem to have a natural aversion response to things that are gross, i.e. things that might contaminate us or give us diseases"
Obviously the emotion disgust has survival benefits, by making us avoid things which "disgust" us decreases our likelihood of infection. A key point here is "avoidance". Usually, "avoidance" is the primary action we take when our emotion of disgust is invoked. But there are ofcourse other actions we might take depending on how it directly affects us.
For example, imagine you wake up one morning and find a pile of dog shit right in the middle of your doorstep. What action will you take? Now ofcourse, upon first contact, your very likely to experience the emotion of disgust and your natural instinct will be to "avoid" the poop. But there is a problem, it affects you because its on YOUR doorstep. Avoiding it forever is not a viable option. So instead, you will most likely, reluctantly, clean it up, using plastic gloves ( avoidance again ).
But now lets say one morning you wake up and find a pile of dog shit on your neighbor's doorstep. What action will you take here? It will ofcourse be complete avoidance, you certainly wouldn't clean it up for your neighbor would you? Since its not on your doorstep, it doesnt directly affect you, and so complete avoidance is likely to be the ONLY action you will take.
Anyway, cut to the chase, something which I have long noticed, and cant seem to shake, is that fat people, especially morbidly obese people, seem to invoke the disgust reflex. I cant speak for others, but when I see the severely obese people, I am revolted. This is despite every logical and rational thought telling me that these people are essentially, victims.
When I see a severely obese person in the street the first thought that comes to mind is "how could you let yourself get like that, its gross" But this is not me thinking, its not my conscious logical rational mind coming up with this, but rather this thought is coming deep from the hindbrain.
The question is, why ? WHY does obesity invoke the disgust reflex? Well, if we go back to the definition etc, we know the disgust emotion has been designed to make us avoid things that could contaminate us, infect us, or things that are likely to be diseased. In this light, it seems as if the body instinctively regards the state of obesity as one of disease. We all know that obesity reduces sexual attractiveness, being disgusted by obese people could be one way our biology protects us from mating with potentially poor gene's.
As an example, physicians are less likely to 'Bond' with overweight patients. Why is that? Does the state of obesity in the patients subconsciously invoke the disgust reflex and subtly guide the physicians to action "avoidance" with them?
'Most' of us who has studied the subject of obesity intensely know all too well the truth. I.E. that obesity is a disease. Something about the adipose tissue has malfunctioned. The dissonance part is what I find interesting. I.E. the dissonance between our bodies instinctively regarding obesity as a disease and the idea that "over-feeding" causes obesity.
The dissonance is that I believe that these 2 points ( i.e. obesity being a disease and simultaneously being caused by over-eating ) are evolutionary incompatible.
In an uncertain, unpredictable, and aggressive world, it should be advantageous to have access to a large of amount of calories. Having a consistent and bulky supply of nutritious food would surely be of benefit to those organisms who can access it. You might even expect this advantage to propagate and advertise itself through the organism by having the organism display a physically and sexually appealing phenotype. Afterall, we all know that emaciation is a massive sexual turn off.
And the more, the better, right? I.E. The greater the quantity of nutritious food we have access to, the more likely it is that we should survive in a harsh world. Right ? And we should advertise that increased chance of survival through consumption of that food which will gives us a physically pleasing phenotype.
But here's the paradox, because apparently, taking advantage of that large cache of food and consuming it leads ( allegedly ) to the state known as obesity, which accordingly, decreases our chance of reproduction through reduced sexual appeal, aswell as ( again, allegedly ) predisposing us to a whole host of other ailments that reduce our chance of survival.
If you believe that over-eating causes obesity, then essentially what your saying is that, paradoxically, having access to and taking advantage of large caches of food which would normally increase an organisms survival, actually leads to a state that reduces survival and chance of gene propagation.
Having access to something which normally increases your survival, actually, decreases your survival if that something ( food ) is overindulged in.
Does that make sense?
Remember that our biology regards the state of obesity as a disease. So its almost like saying your body regards the state of having access to large quantities of food as a disease.