transcript of episode 12: THE ECHOLOCATION CHAMBER, 18th June 2021

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

welcome to the error bar: where brain lies are laid bare

in this episode: can humans learn to echolocate? the hostile media effect, the spread of fake news on twitter & whether brain chemicals predict maths education

here is the brain news on the 18th June 2021:



before the news, i need to address a letter we received following our story about football penalty taking behaviour in episode #11: hand, foot, mouth, balls. a listener writes

"Dear error bar

long-time listener, first time complainer. i love the show, but i also love football

you can only imagine my horror listening to the second story in episode #11, about balls

given the care & attention that went into making the study so bad, my young family & i all thought that the host should have used much stronger language. i mean what good's a [BLEEPING] when you could have said [BLEEP] [BLEEPING], [BLEEP], [BLEEP], or even a [BLEEP] or two?

please do better

Dr Exeter, from Buckinghamshire"

well thank you Doctor. we do take all complaints very seriously






philosophers used to wonder what it was like to be a bat

but instead of just philosophising they should have got out of their armchairs & into a laboratory in Durham, UK, where psychologists trained sighted & blind adults to be bats

well, not quite to be bats, but instead to use their mouths & ears to perceive the size of discs, the orientation of rectangular boards & to navigate a virtual maze

this was an intensive task, with three researchers training 26 volunteers on 50 hours each of practice over 10 weeks to produce mouth clicking sounds & listen for the echoes from nearby objects

as reported in the Daily Mail, the humans learnt to perform rather well, increasing their accuracy, decreasing the time taken & increasing the distance from which they could accurately perceive the objects in front of them. after 10 weeks, healthy young sighted people became almost as good as expert blind echolocators


can humans really echolocate?


despite the unlikely-sounding story, some initial skepticism from your host & the Daily Mail printing the brain the wrong way around, this is a serious study from a research group that has studied this serious topic seriously for a long time

each of the tasks that the volunteers were trained on - size & orientation discrimination, virtual & real navigation - was practised about 20 times a day, two days a week, for 10 weeks

the methods used were good: volunteers were inside a sound-attenuated chamber & blindfolded; the task forced participants to say which of two things - which they couldn't see - was larger, or in which orientation; the researchers included controls for incidental learning & spent a long time with each participant

the article itself is a majestic 34 pages long, highly detailed & fully analysed; the data & results are very clear

i suspect that even philosophers would like this study


trapped in a sound-attenuated chamber for 50 hours, human volunteers can learn to discriminate the size & orientation of objects by mouth-clicking & listening to the echoes


the science was by Norman et al. in Public Library of Science ONE; reported in The Daily Mail by Sam Tonkin on 2/Jun/21

and the brain in brief...



two other reports in the same journal PLoS ONE - which is always a good source of intellectual entertainment - address the perception of bias in printed news media & the spread of fake news on twitter

the first paper introduced me to the concept of the Hostile Media Effect - where people who already hold strong views on an issue perceive bias in neutral media reports

two fascinating aspects are that the effect is stronger when people believe the news has a larger audience & when the author is thought to be a journalist - the same stories presented as a student essay are judged as less biased by the same readers

in the new paper, the author gave two groups of people a story about the Israel-Palestine situation. one group was first asked to assess whether the details of the story were biased; the second was first asked to assess whether the overall story was biased

asking people to focus on whether the details were biased first reduced the overall perception of bias - top tip!

the second paper used mathematical methods to study the spread of fake news on Twitter. the authors argue for a dual-process model, where the first wave of misinformation is later caught by a second wave of correction


is news biased in print & fake online?

no, that was just my headline - you can ignore that

the first paper, by Litovsky, contains a rich introduction to the topic. for example: meta-analyses assessing US news media in 2000 & again in 2020 found little evidence for explicit bias

the Hostile Media Effect is in the eye of the beholder, so it follows that if readers & viewers become more partisan, they will perceive more bias in the traditional news media. Litovsky writes:

"a partisan's fear of the media's ability to persuade a neutral audience in the "wrong" direction on a vital topic is one of the main considerations driving their misperception of hostile bias. a recent poll shows that Americans are much more concerned about bias in the news other people are getting (69%) than about their own news being biased (29%)"

to criticise Litovsky, the Results section is far too long, the data are poorly analysed & there are no error bars on the charts - tut tut. but the effects do seem strong

as for the second article, i just saw a lot of equations & everything went a bit blurry


analysed systematically, the media do not in general show political bias. but as people become polarised on a topic or against a particular source, they begin to see bias where none exists. assessing in detail where bias arises may help


the science was by Litovsky in Public Library of Science ONE, & Murayama et al. in Public Library of Science ONE;



the Irish News, Guardian & Daily Mail all report a study from the University of Oxford into the brain chemistry of children who study maths versus those who don't

the paper reports that the brains of 17-year-olds studying maths at high school level contain different amounts of a particular brain chemical than students not studying maths

these differences were not found in a group of children 2.5 years younger. the authors of the study claim that this particular brain chemistry develops significantly only in those who continue to study maths at high school


is brain chemistry development due to maths?

oh, dear listener, where do i begin?

i started reading this paper with suspicion & as i read, my bias was confirmed

the claim is that 14-year-old students' brains are different from 17-year-olds & that this difference can be explained by 2 or 3 more years of maths

if true, this would be important. so how good is the evidence?

first, while the data look impressive on the page, the largest statistical effects are all behavioural & educational - children who are good at maths are less anxious about it, do better at it & study it longer. the statistical effects in the brain data are all small. every single one of them is small - why?

second, in the 17-year-old group, there are 9 more maths than non-maths students, while the younger group is balanced & smaller - did data collection continue unequally in older students - why?

third, the authors removed so-called 'outlier' data in many different ways. they don't say how much data was removed overall, but Appendix 6 shows different amounts of data were removed on each of seven different criteria for each group separately - why?

fourth, the authors say they measured 8 brain chemicals, with 2 different baselines & adjustments for different brain structures. but only 2 chemicals are reported for one brain area & only 1 chemical for the other - why?

fifth, both groups were tested on three kinds of brain scan, but data from one of these scans was presented only for the older group - why?

sixth, statistical results that are 'not significant' & very weak 'trends' are nevertheless interpreted - why?

finally, the authors' claim depends on the younger, smaller group not showing the same statistical effects as the older group. an alternative interpretation is that this was just a failure to replicate the effects in a second group that was much too small, given the very weak effects found in the older group

the only positive here is that the data are available online if anyone wants to analyse them properly


weak & opaque


the science was by Zacharopoulos et al. in Proceedings of the National Academy of Sciences of the United States of America; reported in Irish News on 9/Jun/21, & The Daily Mail by Sam Tonkin on 7/Jun/21, & The Guardian by @sweale on 7/Jun/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 the University of Nottingham. 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