transcript of episode 7: SEX, CRIME & DRUGS: THE SIN EPISODE, 9th April 2021

[🎶 INTRO: "Spring Swing" by Dee Yan-Kee 🎶]

welcome to the error bar: where brain fudge is filtered out

in this episode: the brain differences between men & women, how neuroscience can reduce murders, why adults drink wine and why children shouldn't eat sugar

here is the brain news on the 9th April 2021:



the Daily Mail and Twitter report what may be the most impressive review article i've ever seen. Professor Eliot & colleagues review hundreds of brain imaging studies over three decades to answer one question: are men's and women's brains different?

their conclusion is that men's bodies are bigger than women's, which means that their brains are 11% bigger too. this 11% difference is an extremely strong statistical effect, & would allow you very easily to distinguish male & female brains with high probability, just by measuring their size. the authors wryly note, however, that there are easier ways to tell the sexes apart

but apart from overall size, do human brains show sexual dimorphism - clear differences in the shape or size of specific parts of the brain?


you can find some differences that are relatively consistent across studies, but when you control for total brain size & are very careful about exactly how the data are analysed, any remaining differences are so small as to be statistically irrelevant


are men & women's brains really the same?


this is an apotheosis of the paper; a titan of a text; a megafauna of a manuscript

the publication of this review has led me to ask the question: what is a scientific paper? some papers are just 'letters', reporting experiments or observations that might have taken a day, or a week or work. others, like this one, take at least several person-years of work

yet each paper, whether it represents a week or years or work will end up as a single entry into research databases and the author's cv. the careers of researchers, their impact, citations of their work, & their influence cannot be measured in the number of papers, citations, or other so-called article-level metrics

only by opening each paper & reading it can we judge a paper's worth. this one is solid gold


this is brain science at its best. the human brain is not sexually dimorphic


the science was by Eliot et al. 2021: Neuroscience and Biobehavioral Reviews; reported in The Daily Mail by Dan Avery on 8/Mar/21, & Twitter by @Lise_Eliot on 20/Apr/21



the Daily Mail covers a review by psychologist Professor Charles Spence - who was my PhD supervisor - on the psychology of wine. focusing on why we buy one wine over another, the Mail says it's the simplicity of the name or the particular animal or 'critter' on the label

professor Spence is quoted as saying it's: 'easier to remember a bottle of Yellow Tail or Gato Negro than a bottle of the Hungarian cserszegi fuszeres'

people are also influenced by colours, corks, the room lighting & background music. so don't try to reproduce your wino-holidays back at home - it won't be quite the same


is all that really true?

it seems a fair reflection. Spence says there's more psychology on wine than on any other food or drink

that may be so, but early in the paper he repeats a dubious neuro-claim by neuroenologist Gordon Shephard that "drinking wine engages more of our brain than any other human behaviour". even if that were true, i can't imagine how that claim could be tested

my advice is to take this long, entertaining review on your next holiday, sit by the beach with a bottle of something with a rhino & drink deeply. just make sure you replicate the experimental findings on your return


many psychologists have studied wine psychology. i imagine they'd all conclude that more research [hic] is required


the science was by Spence 2020: Cognitive Research: Principles and Implications; reported in The Daily Mail by Victoria Allen on 13/Mar/21



if you have wondered why neuroscientists have never discovered the neural mechanisms underlying peoples' enjoyment of watching videos of other people popping pimples, you are not alone

wonder no more. Wabnegger and colleagues at the Institute of Psychology in Graz, Austria, developed a questionnaire to assess 'pimple popping enjoyment' & from 538 respondents they selected 38 who enjoyed watching the most & 42 the least

the study reveals the neural mechanisms of pimple-popping voyeurism in the frontopolar cortex - that's an important part of the brain involved in watching people pop pimples. this brain area was more active for pimple popping compared to control videos & this difference was greater in those who enjoyed the videos




the good news is that the study seems to have been done well and to have found clear effects. at least no-one ever has to do this study again


this large, well-conducted & well-analysed study means that no-one ever need wonder about the neural mechanisms of pimple-popping enjoyment again. nor repeat this study


the science was by Wabnegger et al. 2021: Behavioural Brain Research;

and the brain in brief...



psychologist professor Drew Westen reports in The Washington Post that people aged 16-24 commit half of all murders in the USA, mostly gun-related. this, he argues, is because young people are more vulnerable to mental illness, & their frontal lobes are under-developed

does frontal lobe development stop gun crime?

the article contains a lot of claims & links to a wide variety of sources. some claims are not supported, some links don't work & some of the data are quite old. but, in general, it looks correct, at least, to say that most murderers are young men

but since most of the victims of murder are also young, older non-murderers may have no more developed frontal lobes than younger murderers. instead, they may just have survived this most dangerous period of life

no sources are provided for the frontal lobe development claim, nor for the recommendations of neuroscience on the minimum age for gun ownership. no alternative explanations are considered


while young men do cause most violent gun deaths in the us, this article presents no evidence that this is due to under-developed frontal lobes or mental health problems


reported in The Washington Post by Drew Westen on 5/Apr/21



the Daily Mail warns us that a diet full of sweets early in life affects your child's brain and causes memory problems

the claims are based on a paper in Translational Psychiatry, which links the intake of sugars to the growth of particular bacteria in the gut, and with impairments in performance on memory tests

does sugar harm your child's memory?

maybe. if you're the parent of one of the juvenile male rats who took part in this study

there were 10 control and 11 sugar-treated rats in the first part of the study. it's not clear why there's one extra rat in the sugar group

figure 1 in the paper shows twelve comparisons between the groups on several different tasks & measurements. only one of these statistical comparisons is reported as 'significant', alongside the claim that sugar affects hippocampus-dependent memory function

the statistics for this critical test aren't reported. reconstructing the data from the figure, it is unlikely that this result would stand if the researchers took into account how many statistical tests they performed. correcting for these 'multiple comparisons' is required when many different tests are done


a low-power fishing trip


the science was by Noble et al. 2021: Translational Psychiatry; reported in The Daily Mail by @JoePinkstone on 1/Apr/21



the reports the death in March 2021 of Professor Mary Jeanne Kreek, drawing on an obituary from Rockefeller University, where she worked

Professor Kreek worked on the neurobiology of drug & alcohol addition, & is credited with pioneering work on the development of methadone, a treatment for heroin addition. she was also a vocal proponent of the idea that addition should be treated not as a personal weakness, but as a disorder of the brain


rest in peace


reported in The Scientist by @AsherGJones on 31/Mar/21

[🎶 OUTRO: "Cosmopolitan - Margarita - Bellini"by Dee Yan-Kee 🎶]

it's closing time at the error bar, but do drop in next time for more brain news, fact-checking & neuro-opinions. take care.

the error bar was devised & produced by Dr Nick Holmes from University of Birmingham's School of Sport, Exercise and Rehabilitation Sciences. the music by Dee Yan-Kee is available from the free music archive. find us at the error bar dot com, on twitter at bar error, or email talk at the error bar dot com