Yesterday, Discovery on the BBC World Service was a documentary by Claudia Hammond on disgust – its natural purpose in helping us to steer clear of disease risks, how we learn disgust, its possible role in moral judgment, and even a possible link between disgust sensitivity and political opinions.

As for how we learn disgust, I was pretty unconvinced by the section on this.

One theory (Freud, hey-ho) is that we learn to be disgusted by poo when toilet training takes place. That one is clearly wrong because, Reason Number Blatantly Obvious 1, even in cultures where toilets and nappies are unknown and so there is no transition between the two, people are disgusted by poo. Also, Reason Number Blatantly Obvious 2, as anyone who knows any actual children (other than the Standard Issue Child that scientists seem to use when theorising about how we learn stuff) will tell you, children learn different things including disgust at different stages.

I know people whose children were, or at least seemed, disgusted by the contents of their nappy long before they were able to use a toilet or potty reliably.

And I know at least one child (mine) who is not disgusted by the contents of the toilet when she has done a poo. She knows, because she has been taught, that poo is dirty, that you shouldn’t touch it if you can help it, and that you certainly shouldn’t eat it. But she isn’t disgusted by it. She is if anything curious about it, comparing sizes and shapes and colours with Other Poos We Have Seen. “Look mummy I done a big one and a little one and the big one looks like a sausage. But we don’t eat poo because its horrible. But we do eat sausages because I like sausages and they are yummy.” – does that sound like disgust?

Another theory is that children are hard-wired to be disgusted by certain things, and this just sort of kicks in at, coincidentally, the same time as Western children are often learning to use a toilet and – more importantly in evolutionary terms – Stoneage children are starting to gather and select their own food. That one has a ring of plausibility but must also fail, because in different cultures people are disgusted by different things. OK, pretty much everybody is disgusted by some core items (like poo), but clearly disgust is learned to some extent or why would some poeple find the idea of eating snails or rats disgusting while others think it perfectly acceptable?

Clearly children do learn disgust at some point – or at least they learn at some point what is disgusting. That’s pretty much my theory anyway. That children may be hard-wired to start feeling disgust at some stage, quite possibly at about the time they start making their own food choices while out and about in the wild; but that what disgusts them is learned from their carers.

What ought we to teach our children to find disgusting?

When it comes to disgust that comes from potential disease risks (rotten food, unidentified bugs, bodily wastes, other people’s suppurating pores) I make an effort with Ariel to model not disgust but curiosity mixed with common sense – we want to know what things are but we know it isn’t always sensible to touch or eat them because we know that some things aren’t good for you or don’t taste very nice. This is quite deliberate. I don’t want to teach Ariel to be viscerally disgusted by everyday things, because I don’t see disgust as a very helpful response to most situations. If she decides later in life to work in healthcare, strong reactions of disgust to bodily waste are not going to be helpful to her. If she finds herself in a jungle with nothing to eat but grubs and snakes, disgust will not be a useful tool for her. Armed with common sense and a little knowledge about the world, she doesn’t need disgust.

With luck, the only use Ariel will have for disgust is moral disgust: and that’s a whole nother story. See Part 2.