Hello everyone! Thanks to Tom’s holiday and Stuart’s job we weren’t able to record this week, so we’ve put out a classic paid episode to tide you over. We hope this goes some way to scratching your Studies Show itch.

Most people think it’s obvious that you should wear a helmet when cycling. It might save your life if you fall off and hit your head. Duh.

But over the years, many contrarian arguments have pushed back against this seemingly-obvious point. What if people engage in “risk compensation”, where they cycle more dangerously because they know they’re wearing a helmet? What about if encouraging helments puts people off cycling so they miss the health benefits?

In this March 2024 episode of The Studies Show, Tom and Stuart try to work out who’s right.

Show notes

* The original 1975 study on what’s become known as the “Peltzman Effect”: risk compensation (in this case about car safety)

* Potential evidence for risk compensation in AIDS

* Claims of risk compensation relating to mask-wearing at the start of the COVID-19 pandemic

* The eye-tracking study on helmet-wearing, which used the Balloon Analogue Risk-Taking lab task

* n=27 study on helmets and cycling with one hand on the handlebar

* Study on risk compensation with the following confusing structural equation model diagram:

* Academic cycles around and records thousands of cars passing him while he’s either wearing or not wearing a helmet

* Forbes article about the statistical controversy over these data

* Bizarre study on how motorists “dehumanize” cyclists

* Could helmets make “rotational injuries” worse?

* Cochrane review on cycle helmets and injuries from 1999

* Ben Goldacre and David Spiegelhalter on cycle helmets - “uncertainty… is unlikely to be substantially reduced by further research”

* Systematic review on helmet use and injuries from 2016

* Review of meta-analyses from 2023

* 2006 BMJ article finding “no clear evidence” that mandating cycle helmets reduces injuries

* Negative correlation between cycle numbers and helmet usage, across different countries

Credits

The Studies Show is produced by Julian Mayers at Yada Yada Productions.

This is a public episode. If you'd like to discuss this with other subscribers or get access to bonus episodes, visit www.thestudiesshowpod.com/subscribe

Can adults still grow new neurons in their brains? You’d think we might know the answer to the question of adult “neurogenesis” after more than half a century of neuroscience research. But it turns out we don’t.

In this episode of The Studies Show, Tom and Stuart look into the suprisingly controversial question of adult neurogenesis. Are you “stuck with” the number of brain cells you had as a child, or can you add to that number by making the right choices as an adult? And does it even matter?

This podcast is brought to you by Works in Progress magazine, which this week has a new article explaining why nuclear power is so expensive (spoiler: it relies on an incorrect scientific model that we’ve discussed in previous podcast episodes: the “linear no threshold” model. For a full explanation, along with articles on a dizzying array of other progress-related topics, take a look at www.worksinprogress.co.

Show notes

* Summary post on the debate by Scott Alexander from 2018

* 2000 PNAS study on the brains of London taxi drivers

* 2021 retrospective review of taxi driver studies

* Study comparing passed vs. failed cabbies on “The Knowledge”

* Study putting together neuroimaging research on when the brain peaks in volume and other measures

* 1962 Science study on neurogenesis in rats

* 1999 BrdU study in macaque monkeys

* Famous 1998 study on neurogenesis in the human hippocampus

* 2006 PNAS sudy on testing neocortical neurogenesis using Carbon-14 dating

* 2013 study using similar methods on the hippocampus

* 2018 Nature paper claiming no adult neurogenesis

* Associated commentary article

* Atlantic article describing the controversy by Ed Yong

* 2018 paper finding neurogenesis occuring up to age 79

* 2019 Nature Medicine paper claiming “abundant” adult neurogenesis

* Fair-minded 2019 review paper

* Somewhat angrier 2021 review paper

Credits

The Studies Show is produced by Julian Mayers at Yada Yada Productions. We’re grateful to Claire Wang for her help with researching this episode.

This is a public episode. If you'd like to discuss this with other subscribers or get access to bonus episodes, visit www.thestudiesshowpod.com/subscribe

Do you know anyone who has extremely intense relationships—one minute totally in love with someone; the next, flying into a rage and calling them the worst person ever? It’s possible that they have borderline personality disorder.

Whatever that is. What is a “personality disorder”, anyway? How is one diagnosed? In this episode of The Studies Show, Tom and Stuart discuss a disorder that gets a lot of attention online, but which seems pretty tricky to define. And it’s somehow both surprising and entirely predictable that Tom relates this disorder back to his favourite topic: the Reverend Thomas Bayes.

The Studies Show is brought to you by Works in Progress magazine. On their Substack newsletter, you can find different styles of articles that aren’t part of the main magazine, like this excellent walkthrough of nuclear power technology called “Nuclear Reactors for Dummies”. You can find that and much more at worksinprogress.news.

Show notes

* Mayo Clinic page on personality disorders

* NHS page on Borderline Personality Disorder

* Chimamanda Ngozi Adichie’s 2021 essay “It is Obscene”

* Tom’s Unherd article on this controversy

* 2009 paper on Dissociative Identity Disorder and its overlap with Borderline Personality Disorder

* Comparison of patients with DID and BPD, with a discussion of the overlap

* Pieces by people with BPD diagnoses who’ve regularly changed their dress/style

* Tom’s book on Bayesianism

* Sceptical article about top-down effects on perception

* Paper on the “predictive processing” theory of BPD

* Scott Alexander article on the same topic

* Twin study on the overlap between BPD and antisocial personality disorder, and potential sex differences

* Longitudinal studies on whether people “age out” of BPD

* People higher in “dark tetrad” traits are more likely to enjoy trolling people online

Credits

The Studies Show is produced by Julian Mayers at Yada Yada Productions.

This is a public episode. If you'd like to discuss this with other subscribers or get access to bonus episodes, visit www.thestudiesshowpod.com/subscribe

This is a free preview of a paid episode. To hear more, visit www.thestudiesshowpod.com

Did you miss our live show last week? Good news if you happen to be a paid subscriber: we’re posting the audio in full. Listen as we’re joined by Jesse Singal from Blocked and Reported to discuss the strange “science” of Multiple Personality Disorder (or is it Dissociative Identity Disorder?), as well as digging into the methods of a deeply flawed paper on “top surgery” for gender-dysphoric youth.

To listen to the full show, and to read the show notes, you’ll need to become a paid subscriber at www.thestudiesshowpod.com/subscribe.

The Studies Show LIVE (with special guest Jesse Singal) is this week! Friday 9 May, Conway Hall, London, 8pm. Get your tickets AT THIS LINK or at bit.ly/tss_live.

Welcome to a new series of The Studies Show, all about parenting. We’ll cover the weird claims, fads, and controversies about how you should raise your kids.

In this first episode, which focuses on infancy, we cover some feeding-related topics (an update on breastfeeding, the question of sterilising baby bottles, and the idea of baby-led weaning) as well as “tummy time” and sleep training. Are any of these good for your baby? Are any of them bad? Tom and Stuart look through the evidence.

Let us know which parenting-related claims you want us to look into as the series continues!

The Studies Show is brought to you by Works in Progress magazine. In their recent issue you can find out about surprising policy screwups, the latest fertility techology, the history of the pineapple, and why all that steam comes out from the roads in New York City. It’s all available for free at worksinprogress.co.

Show notes

* Breasfeeding:

* 2024 meta-analysis of health effects of breastfeeding

* 2024 study from Uganda on “topping up” breastfeeding with formula milk

* Bottle sterilising:

* UK NHS advice on bottle sterilisation

* Advice from other countries/states: Ireland, Australia, New Zealand, Alberta (Canada), Israel, Norway, Sweden, US CDC, Texas Children’s Hospital, France

* Lab research on germs passing from hands to bottles

* 2006 observational study on health and sterilising bottles

* Baby-led weaning

* 2017 review and discussion of the history of baby-led weaning

* 2023 Turkish randomised control trial

* 2017 report from the NZ “BLISS” study

* 2022 French Academy of Paediatrics statement on baby-led weaning

* Tummy time

* UK NHS advice on tummy time

* 2023 protocol for a randomised trial

* Very low-quality Indonesian study on tummy time

* Sleep training

* Weird 2012 “cortisol synchrony” study

* Debate about the measurement of cortisol

* 2020 study claiming no effects of sleep training on attachment; response 1; reply from the authors; response 2

* Emily Oster’s ParentData piece on sleep training

Credits

The Studies Show is produced by Julian Mayers at Yada Yada Productions.

This is a public episode. If you'd like to discuss this with other subscribers or get access to bonus episodes, visit www.thestudiesshowpod.com/subscribe

The Studies Show LIVE (with special guest Jesse Singal) is next Friday, 9th of May, at Conway Hall in London. Get your tickets right HERE! Or go to bit.ly/tss_live.

Robert F. Kennedy, Jr. can’t be wrong about literally everything, can he? His latest controversial statement is that he wants to find the “environmental exposure” that has been causing the huge spike in autism rates over the past few decades.

In this episode of The Studies Show, Tom and Stuart look into whether there really is an autism epidemic in the first place—and if there isn’t, why the diagnoses might be going up so quickly anyway.

The Studies Show is brought to you by Works in Progress magazine. This week we discussed the article from the most recent issue about the UK’s land value tax—a cautionary tale of a policy that might sound good on paper, but was utterly cursed in practice. Find this and so many more fascinating articles about human progress at worksinprogress.co.

Show notes

* RFK Jr’s latest claims about autism (and his plans to gather data)

* His statement “I believe autism comes from vaccines”, from 2023

* His “Children’s Health Defence” org from 2015

* CDC data on autism rates in the US

* And similar data from the UK

* A paper on the much lower rates in 1966

* “Early infantile autism” - the original 1944 paper by Leo Kanner

* Hans Asperger’s similarly-timed research

* And on his collaboration with the Nazis

* On “refrigerator mothers”

* Data from after the MMR vaccine was split in Yokohama, Japan

* The DSM-V checklist for autism spectrum disorder

* Scott Alexander’s controversial piece “Against against autism cures”

* 2023 paper on the prevalence of profound autism

* Article on the growing waiting lists for autism diagnoses

* More details on the same

* 2022 paper on the genetics of autism

* Article on rates of extra time in exams in the UK

* Adam Hunt’s post about Renée Thornton, hot-air balloonist

* The Economist’s Bagehot column on the “tyranny of turning up”

* Underdiagnosed autism in girls

Credits

We’re grateful to Adam Hunt for talking to us about psychiatric diagnoses for this episode. The Studies Show is produced by Julian Mayers at Yada Yada Productions.

This is a public episode. If you'd like to discuss this with other subscribers or get access to bonus episodes, visit www.thestudiesshowpod.com/subscribe

This is a free preview of a paid episode. To hear more, visit www.thestudiesshowpod.com

Some scientific controversies are quite surprising (why would the shape of the Earth be controversial, for example?). But some aren’t. The controversy surrounding circumcision—which involves disputed medical science, bodily autonomy, children, disease, religion, sex, tradition, family, and, of course, genitalia—is about as fiery as it gets.

In this paid-only episode of The Studies Show, Tom and Stuart discuss the very sensitive issue of circumcision, covering the health benefits or lack thereof, the alleged risks, and the unbelievably bitter scientists who are battling it out over this unlikely topic.

If you’re not a paid subscriber, you’ll just hear the very tip of the show—you’ll need to go to www.thestudiesshowpod.com/subscribe to read the show notes and hear the whole thing.

Don’t forget THE STUDIES SHOW LIVE—on 9 May in London! You can buy tickets at this link, or by going to bit.ly/tss_live.

What’s going to be the next pandemic? For a long time you might’ve seen news stories about the current threat of H5N1 bird flu, but you probably haven’t paid much attention.

In this episode of The Studies Show, Tom and Stuart try and work out how worried we should be. Are COVID-scarred people freaking out over nothing? Or are we at the start of something much scarier?

The Studies Show is brought you by Works in Progress magazine, a beautifully-produced magazine about science and technological progress. In the current issue you can read articles about new fertility technologies, land value tax, and the one we mentioned in the show, about prehistoric psychopaths. Find it all at worksinprogress.co.

Show notes

* The UK’s “Influenza Pandemic Preparedness Strategy”

* “Of course the UK had a herd immunity strategy”

* Tom’s article on “the men who failed Britain”

* The CDC on types of influenza virus

* 2025 Harvard Medical School article on H5N1 bird flu

* Article on the wild animal deaths caused by bird flu in the current outbreak

* And the same for domestic animals

* Egg prices! 1, 2

* 2011 paper on haemagglutinin in avian flu viruses and its infectiousness to humans

* Pigs as the “mixing vessel” for flu viruses

* And the potential for cows to be the same

* The controversial 2012 Science paper that modified a blue flu virus to be more infectious

* The WHO’s seeming low level of concern about the bird flu outbreak

* Pasteurised milk and its effects on bird flu transmission

* The Swift Centre’s forecasts for the bird flu outbreak

* Scott Alexander’s big piece on bird flu

* The evidence for the effect of antivirals on bird flu

* DOGE cuts to a programme that monitored bird flu in dairy products, and to animal monitoring

Credits

We’re very grateful to Claire Wang for her help with researching this episode. The Studies Show is produced by Julian Mayers at Yada Yada Productions.

This is a public episode. If you'd like to discuss this with other subscribers or get access to bonus episodes, visit www.thestudiesshowpod.com/subscribe

While you here do snoring lie, Open-eyed conspiracy His time doth take.If of life you keep a care, Shake off slumber, and beware: Awake, awake!

…or so said William Shakespeare—about whom there are quite a few conspiracy theories, now we come to think of it. In this episode of The Studies Show, Tom and Stuart do their best to waken you from your own slumber and open your eyes to the psychology of conspiracy theories. Why do people believe them? How do you even define a conspiracy theory? And is there anything we can do to shake people out of their mad “Truther” beliefs?

The Studies Show is sponsored by Works in Progress magazine. In the most recent issue you’ll find fascinating articles on subjects as wonderfully diverse as the land value tax, prehistoric psychopaths, and (as mentioned in this week’s episode) the history of the pineapple, the King of Fruit. Find it all for free at worksinprogress.co.

Show notes

* Loose Change, the viral 9/11 Truther video

* 2023 conspiracy theory review in Annual Review of Psychology

* Tom’s review of How to Talk to a Science Denier

* Iran-Contra; the Invasion of Poland; the Invasion of Manchuria

* The UK infected blood scandal

* Kemi Badenoch accused of giving credence to a “conspiracy theory” about the Netflix show Adolescence

* First study using the specific-conspiracy-list measure of conspiracy belief

* 2013 study proposing a broader questionnaire on conspracies

* 2022 meta-analysis of the correlates of conspiracy belief

* Theory of the psychological motivations behind conspiracy theories from 2017

* Associated meta-analysis from 2022

* Paper proposing that there are “psychological benefits” of conspiracy theories

* New York Times article on left-wing conspiracy theories during the 2024 election campaign

* 2021 paper on left- vs. right-wing conspiracy belief

* 2022 paper with cross-country data on conspiracy belief

* 2024 Science paper on how talking to GPT-4 reduces conspiracy theory belief by 20%

* David Aaronovitch’s book Voodoo Histories

Credits

The Studies Show is produced by Julian Mayers at Yada Yada Productions.

This is a public episode. If you'd like to discuss this with other subscribers or get access to bonus episodes, visit www.thestudiesshowpod.com/subscribe

The Studies Show LIVE! Get your tickets for our live show in London on Friday 9 May at this link.

Blaze it up! It’s time for an episode on cannabis. And just to be clear, not “on cannabis”, but “on, as in about, cannabis”. What’s the evidence that this incredibly popular drug will lower your IQ? What about the question of whether it causes psychosis?

In this toked-up episode of The Studies Show, Tom and Stuart try to find out—and gracefully refrain from any “drug humour” while doing so.

The Studies Show is brought to you by Works in Progress magazine. Why does all that steam come out of the ground in New York City? Why are pineapples the greatest fruit? What on Earth was the Hanseatic League? All of these questions and more are answered in their most recent issue, available 100% free at www.worksinprogress.co.

Show notes

* A summary of the endocannabinoid system

* 2015 review of the evidence on the psychological effects of cannabis

* Famous 1987 study of Swedish soldiers on cannabis and psychosis

* The NEMESIS study

* 2007 systematic review of longitudinal studies of cannabis and psychosis

* 2022 systematic review and meta-analysis with results on dose-response

* Study finding earlier use predicts higher psychosis risk

* 2023 study on sex differences in the cannabis-psychosis relation

* Example of a Mendelian Randomisation study on cannabis and psychosis

* Data on cannabis exposure over time in the UK

* Dunedin Cohort study on cannabis and IQ

* And a response to some controversy over the data

* 2021 systematic review of IQ decline after smoking cannabis

Credits

The Studies Show is produced by Julian Mayers at Yada Yada Productions.

This is a public episode. If you'd like to discuss this with other subscribers or get access to bonus episodes, visit www.thestudiesshowpod.com/subscribe