Adult Picky Eaters UK

For Picky-Eating Adults in the UK and worldwide

Nature & Nurture October 3, 2008

Filed under: causes,food neophobia,research — Claire @ 2:19 am

The New York Times recently reported on a twin study into child food neophobia.  This research, from my old Alma Mater, reports that 78% of the variance in food neophobia is inherited. Genetic. No-one’s fault, no-one’s choice.

“Interesting”, I thought to myself.  So then I went and found the actual article, published in the American Journal of Clinical Nutrition.  You can read it here if you want to (you may find the Discussion at the end quite interesting reading).

The study was based on a cohort of about five and a half thousand pairs of identical and non-identical twins, each member of whom completed a four-item measure of food neophobia (the Child Food Neophobia Scale).  The correlations between CFNS scores for identical twin pairs and non-indentical pairs were then examined, with the result that these correlations were higher for the identical twin pairs, indicating a genetic influence on the neophobia trait.

Using structural equation modelling, it was then found that the model best fitting the data distinguishes between two sources of variation: Genetic, and Non-shared environmental factors/measurement error.  Even if the estimate of the genetic influence at 78% is an over-estimate, it is clear that the genetic component accounts for a majority of the variation. 

The remaining 22% of variance is attributed to a combination of non-shared environmental factors and measurement error, though in what proportions it isn’t clear.  What is clear is that excluding shared environmental factors from the model does not result in a significant reduction of fit.  From which it may be inferred that shared environmental factors have minimal influence in determining a child’s food neophobia, as they have elsewhere been shown to be less influential than non-shared environment in determining other traits.

Which leads me, as a non-expert, to idly wonder, what is the difference between shared and non-shared environmental factors (and which is why I pointed you towards the Discussion in the article, which explains exactly this).  In a nutshell, it is the idea that shared environments can have non-shared effects.  The same home, parents, and culture can be experienced differently by different children, and thus have different effects upon them.  Whether this is because of the environment (eg parents) responding differently to their different offspring, or because of the child interpreting the environment differently is another question.  I’d be amazed if it wasn’t a bit of both.

You may also be wondering how they separated out the effects of these undefined shared and non-shared environmental factors.  Well, the latter component was estimated by subtracting the heritability estimate from the correlation for identical twins.  If you subtract this and the heritability estimate from the total, you are left with the estimate for the non-shared component (plus error).  Neat, huh?

So anyway, what we can take from this study is that while environment (including parenting) accounts for about a fifth of the variation in children’s food neophobia, it is genetic influence that explains the lion’s share.  For children with food neophobia (which I think we all were), it is caused largely by our genes. 

 

ps  Of the many things that I am not an expert in, behaviour genetics is one of them.  So the mechanism by which one’s genetic inheritance might give rise to food neophobia (as I have experienced it) is a mystery to me.  But this study suggests to me that it might be at least partly psychosocial.  To put that theory into better words, that would be to say that one’s genetic endowment leads one to have a psychosocial interaction with one’s environment, that in turn leads to the whole food neophobia thing.  As it might also lead to obssessive-compulsive tendencies, for eg.  Is this a post-hoc rationalisation of my experience?  Or is there no such thing as free will?  I don’t know.  Any thoughts?

Advertisements
 

Ramblings on Terminology August 11, 2007

I’m not exactly fond of the term “picky eating”.  The word “picky” is a bit too close in meaning to the word “choosy”.  And I don’t know about you, but there’s very little about my eating that would constitute choice.  “Picky” seems to be the American version of what I was always labelled as: a “fussy eater”.  But “fussy eating” doesn’t seem quite right either, even if we all know what it means.  I mean, I never made a fuss about not eating stuff. I just quietly refused.  I would only cry if people would be mean to me about it.  And even then, I didn’t want to make a fuss, I just wanted the ground to open up and swallow me.

So what other options are there?  Well, there is “food neophobia” – being phobic of new foods.  In a sense this is quite good, although I’d query the phobia aspect in what I would think of as the true sense:  I don’t feel afraid of fruits and vegetables.  I don’t start shaking, sweating, or feeling sick at the sight of them.  My heart doesn’t start racing, my breathing doesn’t get rapid and shallow.  I can have fruit and veg on my plate quite happily as long as I’m not expected to eat them.  I can even eat a dish that’s had them picked out of.  I can imagine them quite happily too, the idea of them really doesn’t bother me.  I just have a big problem with putting them in my mouth, with having them in my mouth, with chewing or swallowing them.  Maybe some of you feel differently.

The one I like the best is Selective Eating Disorder (SED).  Granted, it still has a connotation that choice is somehow involved, but it’s better than “picky”, it’s more formal, more adult, more official-seeming, and somehow feels less judgemental.

What do other people think?