I especially enjoyed this one. I was struck by how the media, and some scientists, present the significance of a 2.5 or so IQ point effect as important and deleterious when it comes to lead, while such an effect is often dismissed as largely irrelevant when it does not fit the wider narrative of the authors/publications. See, for example, reportage around Karavani et al (2019) and similar papers pointing out the rough gains available at present through selecting embryos using GWAS acquired information: "a tiny difference" (https://www.theguardian.com/science/2021/oct/17/polygenic-screening-of-embryos-is-here-but-is-it-ethical#:~:text=A%20study%20in%202019%20suggested,picking%20the%20“best”%20embryo); "just 2.5 IQ points" (https://www.nature.com/articles/s41436-019-0744-2). I should say that the Karavani paper itself implies the same - it seems like a self-defensive measure - while stating as fact that selection for IQ would be accompanied by a higher risk of positively-correlated anorexia and autism. Of course, the authors have no idea what causes that positive correlation (again, their insistence seems more like a defensive measure against potential negative public opinion); clearly, the correlation could just as easily result from environmental conditions which affect cleverer children more so it is impossible to allocate causation in the way the authors so confidently do. At root, scientists often frame their work in a way which will not scare the horses and the media pick up the science stories they like the framing of (or where they can apply their own).
The statement is made in that article that the "World Health Organisation describes lead as one of 10 chemicals of "major public health concern" requiring action by member states – including Australia – and that there is no level of lead exposure that is known to be without harmful effects." This seems at odds with the information in this podcast.
I especially enjoyed this one. I was struck by how the media, and some scientists, present the significance of a 2.5 or so IQ point effect as important and deleterious when it comes to lead, while such an effect is often dismissed as largely irrelevant when it does not fit the wider narrative of the authors/publications. See, for example, reportage around Karavani et al (2019) and similar papers pointing out the rough gains available at present through selecting embryos using GWAS acquired information: "a tiny difference" (https://www.theguardian.com/science/2021/oct/17/polygenic-screening-of-embryos-is-here-but-is-it-ethical#:~:text=A%20study%20in%202019%20suggested,picking%20the%20“best”%20embryo); "just 2.5 IQ points" (https://www.nature.com/articles/s41436-019-0744-2). I should say that the Karavani paper itself implies the same - it seems like a self-defensive measure - while stating as fact that selection for IQ would be accompanied by a higher risk of positively-correlated anorexia and autism. Of course, the authors have no idea what causes that positive correlation (again, their insistence seems more like a defensive measure against potential negative public opinion); clearly, the correlation could just as easily result from environmental conditions which affect cleverer children more so it is impossible to allocate causation in the way the authors so confidently do. At root, scientists often frame their work in a way which will not scare the horses and the media pick up the science stories they like the framing of (or where they can apply their own).
I enjoyed this episode. It was something I had no knowledge about and an example of how studies can be misinterpreted. So I was surprised when I saw a news item from the Austrlaian Broadcasting Commission about lead being sold at a chain of hardware stores across that country. See https://www.abc.net.au/news/2024-07-14/bunnings-changes-lead-products-packaging-after-concerns-raised/104094432 .
The statement is made in that article that the "World Health Organisation describes lead as one of 10 chemicals of "major public health concern" requiring action by member states – including Australia – and that there is no level of lead exposure that is known to be without harmful effects." This seems at odds with the information in this podcast.
As someone born in 1954 all I can say is my brain has been working ok. Have people got higher IQs now we have unleaded petrol?