Strong behavioral individuality is present at the first day after birth in fish | Hacker News Reader

Strong behavioral individuality is present at the first day after birth in fish

nature.com

118 pointsjonnycomputer90 comments

They have dramatically different personalities in the womb as well, but only the birth mother can spot the difference late in the pregnancy. Examples: Same parents poking the belly with their finger where they feel a limb pushing from within. One baby pushes back. Another baby pulls back and hides the limb. A third one moved around but didn’t pull back. Those personalities very much persisted as they grow. The push backer has great executive thinking now and always insists on their choice for everything. The pulling baby is a great learner - listens well and absorbs prods for new information like a sponge. The third one is still young but loves to explore and catch things. You couldn’t guess the gender by any of that.

A child is really an incredible genetic gamble. It’s like someone grabs legos from multiple people’s genetics, spills an even portion of random pieces from each and builds a new person. If the baby has your looks it can have the other parent’s characteristics and your grandmother’s personality. 1/4 of pregnancies have issues as well - during conception, delivery, genetics. It’s all about how many times you want to roll the dice.

How do you know which child had which behavior in the womb?

Presumably only one of them was in there at once. ;)

I will only comment post coffee from now on.

To be fair to your pre-caffeinated self, I also thought of twins when reading that post. It’s worded in a way that seems to imply twins, at least at first.

Twins or triplets seem like safe assumptions to make at a first read, sure. I wonder if they'd still be able to tell them as well.

I mean, I assumed it was about fish on the first reading. Thankfully some error recovery later it righted itself.

Doesn't the chemical soup also affect this. Is the mother obese, smoking cigarettes, drinking alcohol, high on sugar or caffeine, levels of hormones, etc... I would think these habits would skew the results.

My son's resistance to swaddling at birth was quite predictive of his personality. He also did not like being poked in the belly, would fight back hard. Today he's one of the the most stubborn children in his preschool (as assessed by teachers!). From now on I'll rebrand his stubbornness as "executive thinking".

Fish or no fish, my kids were themselves even before the moment they took first breath.

I audited some embryology, neuropsychology classes in college. Still seems like a miracle, how the kids arrive...

(I won't argue about the magic moment of person-hood, if any. Life in squishy bodies on Planet Earth, we do our best. I'm glad for the chance.)

Don't know why you're getting downvoted. I was always a big believer in humans being programmed by our environment but after having kids I realized how false that is. We all have our own personality from the get go.

Isn't it more likely both contribute in some amount?

This is obvious. But I do think that the way environment is experienced and interpreted is guided by original personality traits, however it is popular to deny that nature has any effect and nurture is everything. Also have noticed this point of view when it comes to dogs ... especially pit bulls or other violent dogs.

Pit bulls owners offer the follow defenses.

1. I think the dog has a cute name

2. I think the dog is cute

3. The dog doesn't attack me

4. Other dogs also attack people

5. It's the owner's fault for lack of training.

These infuriate me more than anything because they are all invalid. You also can't point this out because it's an emotional subject for them

> it's an emotional subject for them

It really is. It is very bizarre when I see people absolute flip out because someone points out that a dog that was bred to be violent ... actually becomes violent. And of course I know it isn't just pits that will attack (I'm looking at you chihuahuas!) but they combine that instinct with power and size and now you have a real problem.

It's hard for people to understand because it's not all-or-nothing. There are plenty of "bred to be violent" dogs that will go their entire lives without doing so. People see that as proof that there's no increased risk, but that's not how statistics works.

> There are plenty of "bred to be violent" dogs that will go their entire lives without doing so.

Most dogs spend almost their entire lives docile. Those bread to be violent are ones that have high odds of a moment or two of uncontrollable violence.

(And if you look, it's almost always because they have a chihuahua or pinscher ancestor.)

New Scientist had an interesting article recently discussing the role of randomness. The suggestion is that it was more important than environment in defining "you". https://www.newscientist.com/article/mg25534050-900-nature-n...

Agree, although I’d wager that prenatal environment still has a big role, especially in cases of poor nutrition, parental stress, and substance abuse.

Same here. I was very much nurture first until i had kids and then it was absolutely crystal clear to me by the end of the first year that the truth is nature first. Nurture matters, but nature is the more powerful force. My first born was as much herself on the first day she was born as she is now at 7yo. The same for my son.

I guess there's a little bit of a misunderstanding here.

The maternal womb is also considered an environmental factor, so by the time they are born the offspring has already been affected, greatly, by the environment. And that's precisely one of the major hypotheses of this paper.

Of course, genetics also influences our personalities greatly, but as seen in this paper with genetically identical fish; even in this case there is shown to be individuality. Now, this paper doesn't say anything about how much of one's personality is genetics or how much is influenced by the environment. What it says is that in genetically identical individuals that grow in (pretty much) identical conditions there is already individuality that's present at the time of birth which is possibly mediated by the pre-natal environment.

Interesting all of the nature-first feedback, because I have 3 kids and their personalities, interests and behaviors have changed significantly over the years. Maybe these life arcs are instilled at birth, but for me as I look back I notice their friends and major life events influencing them.

I also look at my own life and imagine I was born in a different country with different hardships. I can only imagine that some of my personality traits would have expressed themselves differently based on different survival necessities.

As a tech analogy, varying your training data will vary your outputs, even if the model parameters remain consistent.

Does exhibiting different reactions in response to a stimulus have something to do with personhood?

Honestly doesn't surprise me. Our baby kicked like crazy in the womb, reacted to stimuli like music and poking and was very active.

He was born early after my partner's water broke when she wasn't in labour (doctor said likely from our overactive baby puncturing the placenta) and had a lot of attitude from day 1. Kicked a lot, couldn't be swaddled, was super active and even liked the same music (we went to see a symphony before he was born and there was a particularly recognizable track, even now he likes that same track while crying or screaming when he hears other kinds of music). Even now at 3 months he's super active and hitting all the developmental milestones early (and kicks a lot lol).

> 1. Kicked a lot, couldn't be swaddled, was super active and even liked the same music (we went to see a symphony before he was born and there was a particularly recognizable track, even now he likes that same track while crying or screaming when he hears other kinds of music). Even now at 3 months he's super active and hitting all the developmental milestones early (and kicks a lot lol).

I wonder if you have a potential kickball star in the making. Congratulations

Yes, I think this study is one of those "we kind of knew but we never really tested it" studies which to me are some of the most fun.

There is a huge scientific difference between having an idea why something might be and actually managing to test it. Although, of course, this was tested in fish it is still probably very applicable to other species.

The sceptic in me feels this research is extremely fishy. This was done on fish. How much of the observed external characteristics of fish can be attributed to behavior?

They are looking at median swimming speed and how fish swim. Calling this "behavior" is misleading. It could just as likely be developmental physical differences.

They watched fish swim and saw that they are more correlated with themselves than others. Everything else is a very fishy narrative. Many people in this thread judge it by empathy with the story instead of what can be reasonably done.

I hear and share your skepticism, but I'm also skeptical of pushbacks to the ever-growing research and literature on the uniqueness and, well, "personhood" of animals.

The more we learn about animals (see the article on HN ~2 days ago that bees engage in play) the more it seems like they're a lot more like us than we'd like to think. We're smart, and we can try to explain every thing away (like you do in your comment), but there's a pattern that's emerging. It's an uncomfortable pattern and I get why we try to convince ourselves that animals are fundamentally different than we are, but I'm more and more believing that we're all actually a lot more similar than we'd like to think.

A lot of my current thinking is from the book How to be Animal by Melanie Challenger. I recommend it!

I don't judge scientific letter literature with empathy. I can definitely empathize with animals, and I would even say my own cat has shown some behaviors as a kitten that stayed later on (like being easily scared).

Netflix's cat movie that was extremely narrativistic and meant for cat loving audience had more sound basis and plausible methodology to study actual behavior. (Like attachment tests).

This is simply not it. I don't care if it supports my preconceptions - I try to judge objectively. As should more people. This isn't "pushback against personhood of animals". This is pushback against an increasingly narrativistic science, and the inability of so many people to recognize it.

Parenthood is very much a roll of the dice. It’s a game of chance, and you get what you get.

I’m always a bit amused by people who aren’t parents yet who are considering adoption and are very set on a baby as opposed to an older child. Most of their reasoning boils down to the idea that babies are more malleable. As a parent, I do not believe that is the case. They are born as they are, and you can only help them along the path of being true to themselves or trying to be something else. And we can try to help them make good choices. That is it. We don’t get to change who they are.

It is a game of chance for the "base" you have to work with. as a parent, you want the best for your child, no matter what. "Helping" them along implies malleablity whether we like to accept that or not. I don't say this to mean one should always be 100% in control of their child or their decisions. Some lessons are best learned by mistakes. I say this to get the point across that you are a parent and as a parent we have a role to play on our children's lives. which is largely centered around 'survivability '. The terms that make that factor up seem to always be changing.

You can’t change who they are but you can sure miscalibrate a kid aged 0-6 by denying them healthy developmental experiences.

Once that calibration window closes it is difficult if not impossible for most people to ever address the issues.

This is incredibly misleading. Your childs personality is not set in stone after 6. Don't wager yourself safe because you have done your best until 6.

That’s not what I said at all. There is a uniquely critical developmental period before six but you can absolutely mess them up after that too.

Marriage is a roll of the dice, too. Parenthood is the second roll of the dice. So far it's worked out for me. But as I've gotten older, I've seen too many friends tick all the right boxes and do all the right things but they wound up rolling snake eyes.

Good, that's much less surprising than the opposite finding would have been. It indicates that these fish leverage a mixed strategy, which is an evolutionary advantage more often than not, both in terms of direct payoff and in terms of evolvability.

A lot of comments here positioning fish vs humans. There is no doubt everyone has something of a personality.

However this study was performed on genetically and developmentally identical siblings, which is impossible to do in humans (at least ethically) and the interesting part is there was still individual variance, present from the time of birth, that increased over time.

Gene expression is dependent on incredible amount of variables. It'd be a cosmic level of coincidence to have two clones express the same way. That never happens even in single-cell organisms, much less something as complex as fish or human.

"Genes as blueprint" is something that has entered the common knowledge.

At least, it needs to be tempered and modified in the common knowledge by what we have learned "recently" about epigenetics.

And realistically it needs to be modified by everything we don't know too.

I don’t disagree.

To emphasise this point: in almost all other animals, a profound level of motor specialisation is present at-birth. Most animals, are eg., born walking.

Whereas in humans, we are born needing to specialise almost everything during our lifetime -- which has incredibly high costs (ie., many years of being fed without being able to hunt) -- but high rewards: we learn how to conceptualise the world in novel ways, create tools, etc. both largely a product of our ability to specialise our sensory-motor system in response to the actual environment we're in.

There is no reason to suppose that we are analogous to fish in our personalities, but not in everything else -- indeed, there's obvious reasons to suppose the opposite.

Things we take for granted like swallowing, or sneezing involve a great deal of complex and precise motor coordination that babies can do right from the get go.

Human babies are born significantly earlier in their development due to birth canal width VS head size. Without this limitation, they'd be born after 2 years or even more.

This is known as the obstetrical dilemma. It is false and being actively dismantled by new data.

In fish...

Thanks! I wish titles on posts were accurate.

There's no problem in this case; the finding is no less true for humans than fish.

I read a book by a professional nanny and she believed that the behavioral individuality that you would find in babies already at a few months old (liked to sleep a lot, often grumpy, often giggly) would follow them to adulthood. I think there's some truth to that.

I am interested. Would it be possible to share the name of the book? Thank you in advance.

Oh, that's a good question. It's been a long time. I'll do my best to find it but I very few memories about it, other than what I mentioned and that the premise was (in part) to nurture your child based on their personality. It was actually one of the best books I read when my daughter was born, so I'll really try to find it for you.

Edit: I think it's "Secrets of a Baby Nurse," by Marsha Podd. (Maybe. It's been a long time.) I hope that's it because so many of those books were uninformative or simply reassuring (e.g. "Yes, it's normal ..."). This one talks about how your baby is communicating with you from the start and how to watch for that to make both of your lives easier.

Thank you!

This aligns with Montessori beliefs that babies have personalities and are whole humans, not half baked automatons.

Whole humans have personalities too. Doesn't mean they can't change.

That sounds logical to me. I was just pointing out that the headline is linked to a Nature article that is specifically about fish (genetically identical fish) which makes it considerably different than what most people would assume from the fish-less headline

As parent I’d agree that there was some innate behaviors and individuality of personality that persists from the start. No idea how to quantify it but have witnessed it.

and humans

source: am parent of more than one child, each of whom had distinct personalities from birth

New dad here. How do you mean?

I love my 2 month old but her personality mainly seems to be "I enjoy drinking milk and sleeping"

Sure, but if you had 2 different 2 month olds you may notice how they differ

I doubt it not, Elros son of Earendil. Yet I have but one.

How fast they get annoyed, how loud they are, the proportion of time they are delighted vs distraught. Those are all pretty obviously different by two months.

Have another baby and compare.

Have two. They did nothing but cry, eat, sleep, and shit for the first six weeks. After that they’re a little more aware of the world and perhaps developing something that will become a personality pretty soon, maybe by month two or three.

I won’t definitively state newborns don’t have personalities, but my unscientific hunch is sleep-deprived parents are simply projecting and seeing what isn’t really there.

I love both my children, but for the first six weeks they are simply base creatures, outwardly.

All three of our children were obviously different in the womb.

The oldest was pretty lazy and quiet during the day, but did get bouncy when my wife tried to sleep. The combination of couch potato and getting active when stimuli stops and the boredom hits is present in the kid to this day.

Middle child was super-active the whole way through labor and came out active. Was surfing furniture standing up at eight months.

I could go on at length.

Main point is - we saw the differences before they were born.

My first kid was never content unless she was being held, she was very fussy during the witching hour, and never slept long stretches at night. Our second kid was immediately different--she never really cries and is very content, she just wants to be nearby and have a view of the parent. She also sleeps through the night in much longer stretches. There are definitely differences in babies immediately from birth.

I have 3, and they were all extremely different from even before birth. My first would kick your hand off if you held it on her mom's belly, continue kicking until you removed it. She's continued to be as stubborn as a mule and protective of her space. She didn't cry too much, was never needy, and still remains very independent. My second was a colicky baby that always wanted to be held. He's 12 now and still won't sleep in a room alone, loves attention. My third is only 2, and has been by far the easiest going. She has always been easy to soothe, and lights up rooms. Maybe your babies are just very similar, or maybe you're just inobservant.

This should be something that is easy to study! There are many parents with multiple kids (I am one!) and they can tell you if all of them were just a tabula rasa with no personality or if they were all different on day one. I will say that all of mine were. Of course environment guides how they grow but the way they interact and interpret the same environment seems to be different.

In general these sort of studies can be generalized to other species as the genetic mechanisms in animals are similar. This study has more to do with the relationship of genetic, environmental and pre-natal environmental and individuality so none of it is really specific to fish.

Of course, humans are still a different species and our offspring have a much more complex ontogenesis and so I would venture and say our individuality development is even more sensitive to pre-natal environmental, post-natal and genetic factor changes.

But ultimately, we are all animals here so we are governed by very similar broad rules.

There's a certain sort of determinism involved in using past behavior to predict future behavior. That kind of thinking is prerequisite for a social credit system

For some reason, people really love to make these kinds of predictions. They sound true and are fun to talk about, and they make sense to pretty much everyone.

At the same time, the way we talk about something conditions how we see it, how we react to it, and consequently what it is

The environment being so carefully controlled to be the same is kinda one example. I don't think it's as identical as they are claiming — behavioral science is littered with these claims that are later shown to be false — but showing X percent of variance associated with the individual in the absence of environmental variation is not the same as showing X percent in the presence of significant variation. Let's say you tried to change some of the fish, for example.

It's an interesting paper but full of big-picture issues.

Misleading headline. The *clonal* fish were separated on day one and the differences were observed seven weeks later. The separation occurred early to prevent the other clonal fish from having an influence on each other's later behavior. All the fish had the same DNA. This is more analogous to twin studies than not.

Those keeping guppy fish know that the males have one single thing in mind: Sex

Fish are hatched, not born.

My two sons were different from day one. It gives me a lot of comfort to know, as a parent, that it wasn't all up to how I brought them up.

In a similar vein, I don't understand people who want to know their child's gender before birth. Even ignoring the whole transgender and non-binary aspect, it's like they want to have their kids figured out at birth. Just because this one will be born with a penis, or that one with a vagina, doesn't mean you know anything about who they are and who they will become.

I don't identify with this at all. There is choosing a name, buying clothes, decorating (not my thing personally but definitely a thing). Plus imagining your new baby as part of your life. Boiling it down to knowing their sex organ is pretty reductive and not in line with the feelings of anyone I know.

For the first month, it really doesn't matter, really. Furniture is the same, car seats the same, clothing, sure, but you can buy that any time and does not require planning. And as it regards names, just have agreed upon two options, one for each case.

Or just find out because it doesn’t matter either way? Or don’t. I wanted to know for both my children. It didn’t make any difference, but I still just wanted to know because I could and was curious.

> There is choosing a name

So choose two...

> buying clothes

Tons of gender neutral clothing especially for newborns... Ours has a lot of green, white, beige, gray. Plus some pink and blue because who says boys can't wear pink? (And because lots of people gave us lots of baby shit)

> decorating

Heavily gendered rooms are strange to me... And who's to say the child will even like it?

> Plus imagining your new baby as part of your life.

Honestly not knowing the sex was helpful in not trying to guess how they'd be and fit into our life... We were surprised by his sex and are constantly surprised by his attitude.

It's getting harder every day to tell what is/isn't parody.

So you think if we don't paint our son's room blue and dress him in nothing but camo he'll want to chop his balls off later?

No, you Americans just have ridiculous views (left and right).

Get help.

Yes saying that what a 3 month baby wears doesn't matter that much is so extreme.

I thought the same thing

It sounds like they just had a misinterpreted ultrasound.

* Honestly not knowing the sex was helpful in not trying to guess how they'd be and fit into our life... We were surprised by his sex and are constantly surprised by his attitude.

I hate the idea of having my kid looking like a communist because of gender roles.

Why does the sex matter then? If you know, you know, it was you who was creating certain imagery, not the childs sex organs. So as others have said, I'd find out because of curiosity and I could leave at that.

> looking like a communist

What does a communist even look like?

The Soviet system of centralized production and distribution of clothes was forced on East European countries after 1948, when the communists seized power, regardless of their previously higher levels of technical and stylistic skill in clothing design and production. The East European communist regimes embraced early Soviet ideology, officially rejecting Western fashion. East European communist dress was not only born inside a reality burdened with postwar material poverty, but also inside a reality stripped of all previous clothing references. Clothing was forbidden to evoke beauty or elegance. It was officially claimed that functional, simple, and classless communist dress, which would fulfill all the sartorial needs of working women, would result from serious scientific and technical research.

https://www.encyclopedia.com/fashion/encyclopedias-almanacs-...

Often a lot of dull, drab neutral colours…

Well if you have a baby you'd know that function is kind of important in baby clothing. They're not exactly cooperative when getting dressed... Not to mention, they can't pick their own clothing. Parents do. Regardless, our kid has some cute/fun clothing (a fleece bear onesie for example), some chosen by us, some chosen by others, and most of it is functional. A bald 0-3 month baby isn't going to wear a dress nor a suit.

Were your sons fish? the article uses fish.

> Poecilia formosa

If sex doesn't matter, what difference does it make if you know before birth? If you are getting sonograms done, the doctor will know and be able to tell you pretty early on. Is there some benefit to not knowing?

Or maybe it’s just so easy to find out the gender during medical screenings that you have to not look on purpose, so why not look? Then you don’t have to go out of your way to plan for two (pretty much) mutually exclusive possibilities.

Parents who want their children’s paths predestined don’t have a “knowing the child’s gender” problem, they have a “you can’t control your child’s basic personality” problem.

Reply on news.ycombinator.com