Framed: The gendered political broadside might have stirred up more careful thought but you do realise that as far as empirical evidence goes politics has little place in determining bias. I also see you've pre-empted the inference that this will somehow have a place in the moral vegetarianism debate, but insofar as the appeal to naturalism is a fallacious one, this carries no actual moral commitment whatsoever. I've used
it takes life to make a life as grounds for arguing that there is no need for a strong categorical commitment either way- a balance between all lifestyles is most responsible and best for the ecosystem.
That said, I'm willing to bet that there is a real bias, or even a series of them. The quickest expression I have on hand is something I'm going to quote from a friend:
The likely explanation for this is that vegetarianism is an upper-middle class fashion statement.
This was partially denied in the article, but I still have my strong reservations. Knowing basic principles of epidemiology, I have a host of questions that would verify systematic biases, strength and power of the evidence and therefore how seriously we can take such a study. There are a number of possible inconsistencies that the article allows for but does not explore.
For those interested in gender distinctions, I would also refer to normative values for gender bias in IQ tests, consider why females in the upper socio-economic classes are more inclined to be vegetarian (consider Liz O'Neill's response), and obviously look for examples of confounding variables. Personally I think that such a study is fundamentally flawed (this looks to be an ad-hoc long term cohort study but the use of IQ tests is controversial as the readings vary wildly across the children age bracket and any statistically significant margin away from the mean), and wonder how it could ever have been approved for in the first place, as generally all it
does inspire is moralistic propoganda predicated on BS claims. Finally, people also need to take stock on what the
mean actually means. Its import can be high, or it can be very limited, as the broad spectrum of IQ scores itself demonstrates.
For the record, I'm not ever going to take any report that claims an IQ test is a comprehensive measure of "intelligence" seriously. It is certainly impossible to construct a meaningful intelligence test based on natural ability alone; it necessarily entails exposure, which a higher SES is biased towards.