An alternative beauty in parenthood

Vela has an amazing essay by a mother of a child with a rare chromosomal deletion. Put aside all your expectations about what this article will be like: it is about the hopes and reality of having a child, but it’s also about so much more.

It’s an insightful commentary on the social expectations foisted upon pregnant women.

It’s about the clash of folk understanding of wellness and the reality of genetic disorders.

It’s about being with your child as they develop in ways that are surprising and sometimes troubling and finding an alternative beauty in parenthood.
 

Link to Vela article SuperBabies Don’t Cry.

neurotransmitter fashion

A graph of scientific articles published per year which mention four major neurotransmitters in their title:

What I take from this is

  • Dopamine is king! And with great popularity, comes great misrepresentation.
  • What happened to glutamate research in the mid 1990s?
  • The recent hype about oxytocin doesn’t seem to be driven by a spike in the primary literature.
  • Nor does the hype about serotonin. Yes, publications increase on this neurotransmitter, but not compared to glutamate. And most people haven’t heard about glutamate, despite it being more abundant.

Technical note: I scraped the data from google scholar using scholar.py by Christian Kriebich

Update: here’s the raw data, should you want it

hormones, brain and behaviour, a not-so-simple story

There’s a simple story about sex differences in cognition, which traces these back to sex differences in early brain development, which are in turn due to hormone differences. Diagrammatically, it looks something like this:

simpleCordelia Fine’s “Delusions of Gender” (2010) accuses both scientists and popularisers of science with being too ready to believe overly simple, and biologically fixed, accounts of sex differences in cognition.

There is an undeniable sex difference in foetal testosterone in humans at around 6-8 weeks after conception. In Chapter 9 of her book, Fine introduces Simon Baron-Cohen, who seems to claim that this surge in male hormones is the reason why men are more likely to be Autistic, and why no woman had ever won the Fields Medal. So, diagrammatically:

simple_mathsThis account may appear, at first, compelling, perhaps because of its simplicity. But Fine presents us with an antidote for this initial intuition, in the form of the neurodevelopmental story of a the spinal nucleus of the bulbocavernosus (SNB), a subcortical brain area which controls muscles at the base of the penis.

Even here, the route between hormone, brain difference and behaviour is not so simple, as shown by neat experiments with rats by Celia Moore, described by Fine (p.105 in my edition). Moore showed that male rat pups are licked more by their mothers, and that this licking is due to excess testosterone in their urine. Mothers which couldn’t smell, licked male and female pups equally, and female pups injected with testosterone were licked as much as male pups. This licking had an extra developmental effect on the SNB, which could be mimicked by manual brushing of a pup’s perineum. Separate work showed that testosterone doesn’t act directly on the neurons of the SNB, but instead prevents cell death in the SNB by preserving the muscles which it connects to (in males). So, diagrammatically:

snbOne review, summarising what is known about the development of the SNB, writes ‘[There is] a life-long plasticity in even this simple system [and] evidence that adult androgens interact with social experience in order to affect the SNB system’. Not so simple!

What I love about this story is the complexity of developmental causes. Even in the rat, not the human! Even in the subcortex, not the cortex! Even in a brain area which direct controls a penis reflex. Fine’s implicit question for Baron-Cohen seems to be: If evolution creates this level of complexity for something as important for reproductive function, what is likely for the brain areas responsible for something as selectively-irrelevant as winning prizes at Mathematics?

Notice also the variety of interactions, not just the number : hormones -> body, body -> sensation in mother’s brain, brain -> behaviour, mother’s behaviour -> pup’s sensation, sensation -> cell growth. This is a developmental story which happens across hormones, brain, body, behaviour and individuals.

Against this example, sex differences in cognition due to early hormone differences look far from inevitable, and the simple hormone-brain-behaviour looks like a crude summary at best. Whether you take it to mean that sex differences in hormones have multiple routes to generate sex differences in cognition (a ‘small differences add up’ model) or that sex differences in hormones will cancel each other out, may depend on your other assumptions about development. At a minimum, the story of the SNB shows that those assumptions are worth checking.

Previously: gender brain blogging

Paper: Moore, C. L., Dou, H., & Juraska, J. M. (1992). Maternal stimulation affects the number of motor neurons in a sexually dimorphic nucleus of the lumbar spinal cord. Brain research, 572(1), 52-56.

Source for the 2009 claim by Baron-Cohen claim that foetal hormones explain why no woman has won the Fields medal: Autism test ‘could hit maths skills’.

In 2014 Maryam Mirzakhabi won the Fields medal.

Diagrams made with draw.io

A neuroscientist podcaster explains…

There’s a great ongoing podcast series called A Neuroscientist Explains that looks at some of the most important points of contact between neuroscience and the wider world.

It’s a project of The Guardian Science Weekly podcast and is hosted by brain scientist Daniel Glaser who has an interesting profile – having been a cognitive neuroscientist for many years before moving into the world of art and public engagement.

Glaser takes inspiration from culture and current affairs – which often throws up discussion about the mind or brain – and then looks at these ideas in depth, typically with one of the leading researchers in the field.

Recent episodes on empathy and music have been particularly good (although skip the first episode in the series – unusually, there’s a few clangers in it) and they manage to strike a great balance between outlining the fundamentals while debating the latest ideas and findings.

It seems you can’t link solely to the podcast but you can pick them on the page linked below.
 

Link to ‘A Neuroscientist Explains’

Why women don’t report sexual harassment

189px-milgram_experimentJulie A. Woodzicka (Washington and Lee University) and Marianne LaFrance (Yale) report an experiment reminiscent of Milgram’s famous studies of obedience to authority. Reminiscent both because it highlights the gap between how we imagine we’ll respond under pressure and how we actually do respond, and because it’s hard to imagine an ethics review board allowing it.

The study, reported in the Journal of Social Issues in 2001, involved the following (in their own words):

we devised a job interview in which a male interviewer asked female job applicants sexually harassing questions interspersed with more typical questions asked in such contexts.

The three sexually harassing questions were (1) Do you have a boyfriend? (2) Do people find you desirable? and (3) Do you think it is important for women to wear bras to work?

Participants, all women, average age 22, did not know they were in an experiment and were recruited through posters and newspaper adverts for a research assistant position.

The results illuminated what targets of harassment do not do. First, no one refused to answer: Interviewees answered every question irrespective of whether it was harassing or nonharassing. Second, among those asked the harassing questions, few responded with any form of confrontation or repudiation. Nonetheless, the responses revealed a variety of ways that respondents attempted to circumvent the situation posed by harassing questions.

Just as with the Milgram experiment, these results contrast with how participants from a companion study imagined they would respond when the scenario was described to them:

The majority (62%) anticipated that they would either ask the interviewer why he had asked the question or tell him that it was inappropriate. Further, over one quarter of the participants (28%) indicated that they would take more drastic measures by either leaving the interview or rudely confronting the interviewer. Notably, a large number of respondents (68%) indicated that they would refuse to answer at least one of the three harassing questions.

Part of the difference, the researchers argue, is that women imagining the harassing situation over-estimate the anger they will feel. When confronted with actual harassment, fear replaces anger, they claim. Women asked the harassing questions reported significantly higher rates of fear than women asked the merely surprising questions. Coding of facial expressions during the (secretly videoed) interviews revealed that the harassed women also smiled more – fake (non-Duchenne) smiles, presumably aimed at appeasing a harasser that they felt afraid of.

The research report doesn’t indicate what, if any, ethical review process the experiment was subject to.

Obviously it is an important topic, with disturbing and plausible findings. The researchers note that courts have previously interpreted inaction following harassment as indicative of some level of consent. But, despite the real-world relevance, is it a topic that is it important enough to justify employing a man to sexually harass unsuspecting women?

Reference: Woodzicka, J. A., & LaFrance, M. (2001). Real versus imagined gender harassment. Journal of Social Issues, 57(1), 15-30.

Previously: a series of Gender Brain Blogging

Much more previously: an essay I wrote arguing that moral failures are often defined by failures of imagination, not of reason: The Narrative Escape

The Social Priming Studies in “Thinking Fast and Slow” are not very replicable

train_wreck_at_montparnasse_1895In Daniel Kahneman’s “Thinking Fast and Slow” he introduces research on social priming – the idea that subtle cues in the environment may have significant, reliable effects on behaviour. In that book, published in 2011, Kahneman writes “disbelief is not an option” about these results. Since then, the evidence against the reliability of social priming research has been mounting.

In a new analysis, ‘Reconstruction of a Train Wreck: How Priming Research Went off the Rails‘, Ulrich Schimmack, Moritz Heene, and Kamini Kesavan review chapter 4 of Thinking Fast and Slow, picking out the references which provide evidence for social priming and calculating how statistically reliable they:

Their conclusion:

The results are eye-opening and jaw-dropping.  The chapter cites 12 articles and 11 of the 12 articles have an R-Index below 50.  The combined analysis of 31 studies reported in the 12 articles shows 100% significant results with average (median) observed power of 57% and an inflation rate of 43%.  …readers of… “Thinking Fast and Slow” should not consider the presented studies as scientific evidence that subtle cues in their environment can have strong effects on their behavior outside their awareness.

The argument is that the pattern of 100% significant results is near to impossible, even if the effects known were true, given the weak statistical power of the studies to detect true effects.

Remarkably, Kahneman responds in the comments:

What the blog gets absolutely right is that I placed too much faith in underpowered studies. …I have changed my views about the size of behavioral priming effects – they cannot be as large and as robust as my chapter suggested.

The original analysis, and Kahneman’s response are worth reading in full. Together they give a potted history of the replication crisis, and a summary of some of the prime causes (e.g. file draw effects), as well as showing off how mature psychological scientists can make, and respond to critique.

Original analysis: ‘Reconstruction of a Train Wreck: How Priming Research Went off the Rails‘, Ulrich Schimmack, Moritz Heene, and Kamini Kesavan. (Is it a paper? Is it a blogpost? Who knows?!)

Kahneman’s response

Sex differences in cognition are small

Lately I’ve been thinking about sex differences in brain and cognition. There are undeniable differences in the physical size of the brain, and different brain areas, even if there are no ‘female’ and ‘male’ brains categorically. These physical differences do not translate directly into commensurate differences in cognition. Indeed, there is support for a ‘gender similarities hypothesis’ which asserts that on most measures there is no difference between men and women.

Most, but maybe not all. There are a few areas of fundamental cognitive ability where gender differences seem to persist – mental rotation, vocabulary and maybe maths. But these differences are small. To see how small, I put them on the same chart with the physical differences and a few other behavioural differences for perspective.

Standardised mean differences (Cohen’s d effect size) for various gender differences in brain, behaviour and cognition:

gender_effectsReferences and calculations at the end of this post, below the fold. And if you need a primer on what is meant by standardised difference then go here.

Even with these, small, observed differences in cognition, we don’t know what proportion is due to contingent facts, such as the different experience and expectations men and women encounter in their lifetimes, and what proportion is immutable consequence of genetic difference in sex.

One possibility for why there is a mismatch between physical differences in the brain and cognitive differences is the possibility that structural differences between male and female brains may actually serve to support functional similarity, not difference.

For more, so much more, on this, see the special issue of Journal of Neuroscience Research (January/February 2017) on An Issue Whose Time Has Come: Sex/Gender Influences on Nervous System Function.

Includes: Grabowska, A. (2017). Sex on the brain: Are gender‐dependent structural and functional differences associated with behavior?. Journal of Neuroscience Research, 95(1-2), 200-212.

Previously: Gender brain blogging

Continue reading “Sex differences in cognition are small”