I never thought a reduction could result in an improvement. The brain is so fascinating!
"The researchers found "substantial" reductions in the volume of grey matter in the brains of first-time mothers.
The grey matter changes occurred in areas of the brain involved in social interactions used for attributing thoughts and feelings to other people - known as "theory-of-mind" tasks.
The researchers thought this would give new mothers an advantage in various ways - help them recognise the needs of their child, be more aware of potential social threats and become more attached to their baby."
I'd be slightly careful here about separating out the findings from the speculation.
The study[1] looked at what changed in the women's brains, the regions in which it changed, and then tested to see which areas 'lit up' when viewing a picture of their own child vs. other children. In addition measurements were taken over time to see how permanent the changes were.
The reasons for change and the actual/quantitative impact of the changes would have to come from another study. While what the "researchers thought" is interesting, it's not supported by any evidence, i.e. no measurements were taken to see if any of the suggested improvements were present.
FWIW my wife underwent a drastic personality change after giving birth, and I would definitely agree with this being one of the symptoms. But just one data point of course.
As a counterpoint, my wife gave birth to our daughter a couple of years ago and I saw no noticeable personality change. She was perhaps more emotional at first but that seemed as much a result of sleep deprivation as the actual pregnancy and birth.
The part of my experience that seemed relevant to the article:
areas of the brain involved in social interactions used for attributing thoughts and feelings to other people - known as "theory-of-mind" tasks
...was that I noticed she wouldn't differentiate between whether something had actually happened or not. For example, she could get quite angry at someone for something they didn't do, just thinking they "might" do it.
Then again, maybe this personality aspect had been there all along and I had never noticed until the additional stress of having a new baby.
EDIT: Please don't downvote me for answering a question.
I really don't want this to come across as rude, because I don't mean to single you out or invalidate your experience (or your contribution to discussion!).
That said, what is the purpose of offering your anecdotal experience if you acknowledge that it is an n=1 datapoint? I understand that it's in good faith to acknowledge that your personal experience doesn't offer any statistical rigor to an interpretation of the foregoing article, but in my opinion your comment primes other readers in the discussion to subconsciously accept certain interpretations that aren't justified by the research. The main takeaway of your comment is "For what it's worth, I have an anecdote confirming an interpretation of the data that is not presented in the original study", and while you follow it up with the anecdote-acknowledgement, the "damage is done" so to speak. You've already opened Pandora's Box with regards to your subtle confirmation of the unsubstantiated interpretation.
In my experience it takes conscious effort not to allow anecdotes to impact interpretation of data, and while I don't think you're doing it purposefully, I believe it's counterproductive to the parent comment's point to offer an anecdote to the discussion while simultaneously acknowledging that the anecdote does not in any way prove the interpretation.
Because this is Hacker News, not the Journal of the American Medical Association. It's a community, and since it's acknowledged by the poster not to be a scientific observation, I'm not sure he needs corrected on it.
That's a fair point, and maybe I'm just demonstrating a personal bias for a particular type of discussion that isn't reflected on Hacker News. However, I didn't try to "correct" the grandparent commenter so much as show that while an acknowledgement of an anecdote is made in good faith, it doesn't take away from the overall impact on the audience. We may not be researchers peer reviewing the work of colleagues here, but we can still strive for a certain level of scientific literacy and decorum in our discussion.
Stated another way - if this were an article about computer science instead of neuroscience, would you expect the overall discussion to be stronger, the same or weaker compared to this discussion in terms of rigor? Furthermore, would you think that rigor was warranted on this forum (these aren't rhetorical questions, I'm curious)? I understand that disciplines like neuroscience allow us to relate with the science a bit (it's tempting to retroactively interpret our experiences with novel research!) but comments offering anecdotes, even with those expressly accounted for, allow biases to be couched in between legitimate data. I certainly think the grandparent comment would be challenged similarly if this was a psychological study with the current concerns about replication.
> what is the purpose of offering your anecdotal experience if you acknowledge that it is an n=1 datapoint?
What is the purpose of using large-n datapoints anymore when the primary motivation of "research" is becoming less about finding meaningful information and more about getting published (in for-profit, paywalled "journals") so you can get more grant money for your institution?
Haven't you seen the articles in the last year or about little scientific research is even reproducible anymore ? You can just repeat your experiment until you get the results you want to see.
> That said, what is the purpose of offering your anecdotal experience if you acknowledge that it is an n=1 datapoint?
I'm not sure I understand your question...the grandparent of my comment noted an aspect of the article, someone replied to that casting doubt, and I replied (that fwiw) I had observed similar behavior.
Historically one couldn't draw conclusions without an exhaustive study, does that now also apply to anecdotes on forums? I've read hundreds of anecdotes on HN so far this morning, are all of those inappropriate?
> Historically one couldn't draw conclusions without an exhaustive study, does that now also apply to anecdotes on forums? I've read hundreds of anecdotes on HN so far this morning, are all of those inappropriate?
In a word, yes.
I'd push back on the word "inappropriate" specifically though. Whether they are inappropriate is a matter of context; in the context of a discussion about a study published in Nature Neuroscience, an anecdote that supports a causal relationship between the research and unsubstantiated interpretations of the data is inappropriate, in my opinion.
I think the disconnect here is a difference of approach - I am approaching this discussion as one of analysis, while there are other commenters approaching this as a friendly conversation. There's no right or wrong there, but I feel compelled to point out that the latter approach is how biased data frequently becomes parroted without real support in the original research.
In your original comment, you mentioned that your wife exhibited a significant personality change that appears to match the article. You also point out that you realize this is an anecdote. However, there is research[1][2] that demonstrates people will begin to internalize what they continually read, regardless of whether or not they know it is not true. In a discussion about a loaded topic such as pregnancy, where people are commiserating with each other or exchanging anecdotes, my claim is that it is not merely enough to acknowledge that the anecdote doesn't represent datum. Rather, that will not do anything to prevent the anecdote from having a positive impact on the audience's impression of the research (positive here used in the dialectic sense).
Of course, I'll admit I'm a stickler for this. Whether or not this is a point worth making in subsequent threads is up to the HN upvote/downvote roll :)
Ah ok, I see where you're coming from now. It is a valid point, but then at the same time I'm a stickler for suppression of free speech, so some sort of a meta-discussion was inevitable wasn't it! :)
As long as people realize it doesn't prove anything, there's still some value to it. Sure, it's not following proper scientific methods, but HN comments are not for peer-reviewing scientific findings. Sometimes, readers may benefit from having a conversation with a human behind that n=1 data point.
Seems logical: a temporary "this isn't the time to think about the needs of your extended family" signal lasting just up until the point the kid can toddle around would be survival enhancer.
By being less able to read into the multiple possible reactions of a person; e.g.
- "they're looking at my baby because she's cute"
- "they're looking at my baby because they want to kill him"
- "they're looking at my baby to feign interest in my life"
...the mothers are able to focus on the important options:
- "they're probably a threat"
- "they're probably not a threat"
While this would be a good followup study, I want to call out that it's not supported in the original research whatsoever. Presently, it's just speculation based on which areas of the brain are impacted by the grey matter alterations.
Following that argument then simple-minded businessmen or people with a Manichean world-view should be great at taking care of babies, since they make quick judgement calls?
That's a function of how well calibrated are those judgement calls with well-being of the baby.
Soldiers who make quick judgement calls are better than ones who don't; but they're trained to have their judgement properly calibrated with the task at hand.
You're not missing anything. As user joncrocks comments in this subthread, the actual study[1] does not do anything other than measure the structural changes. The "why" of the grey matter alterations (which appear to primarily occur in the prefrontal cortex and hippocampus regions) and their resulting impacts are not quantified at all beyond offering hypotheses for future studies.
It is disingenuous to call these alterations "improvements" and any attempt at extrapolating the results to real-world improvements in e.g. perceiving threats in strangers is complete speculation. There simply isn't any material in the research to justify labeling these changes as positive or negative.
The authors do give a few good-faith remarks about how these changes could improve e.g. facial recognition (for a certain subset of defined metrics to satisfy "improve", of course), but there isn't actually evidence to support this. It's conjecture based on what we know of the brain.
What we can reasonably say based on this research is that women experience grey matter reductions after pregnancy that may have an impact on their executive and social functioning skills (if we extrapolate from the specific areas impacted in the brain). Obviously, this depends upon the statistical rigor involved in the study's interpretation as well, but I'm not going to comment on that.
As a meta point, this study is another disappointing demonstration of the way in which the media frames legitimate studies and primes scientific discourse. It is excellent research that stands on its own, and a great contribution to neuroscience at that. There is no need to color the results with speculation, which is cleverly couched between actual results in an optimal context. My partner brought this study up with me at dinner last night, as it had already started making the rounds. Naturally, when I asked her for concrete examples of these "improvements" and how they were supported by the study, she couldn't offer any, and was annoyed by my questioning. Not only did the articles do an intellectual disservice to her (and others!) by priming her expectations with illegitimate results, they encouraged a "pre-chewed" version of the study that would not hold up to real challenge or inquiry. I subscribe to Nature (and many of its subjournals), and I absolutely refuse to read scientific literature from secondary sources if I can find the study. But this isn't a reasonable expectation for everyone; in a world where most people aren't going to click through to read a 4 - 20 page study, this sort of coverage diminishes the general public's appreciation of scientific results at best, and encourages dangerous interpretations of legitimate data at worst.
"The researchers found "substantial" reductions in the volume of grey matter in the brains of first-time mothers. The grey matter changes occurred in areas of the brain involved in social interactions used for attributing thoughts and feelings to other people - known as "theory-of-mind" tasks. The researchers thought this would give new mothers an advantage in various ways - help them recognise the needs of their child, be more aware of potential social threats and become more attached to their baby."