[djtango]

Isn't that amazing? That we can help people extraneously without having to administer chemicals which have a nonlocalised effect on our bodies.

There's still so much to learn I recently heard that new fathers see a reduction in testosterone. How does having a baby chemically alter a man!? What's the stimulus and mechanism for that...

[llamaimperative]

Why couldn’t it just be cognitive? Your endocrine system is not totally isolated from your cognition.

It’s fairly apparent how fathers amped up on testosterone could be worse for offspring survival than those who have a drop, so the evolutionary pressure is pretty clear, then the mechanism is readily explained by “they know that they have a child.”

How does adrenaline get released when you see a dangerous situation with merely your eyeballs?

[edmundsauto]

As a recent father: low sleep.

[nonameiguess]

This plus added stress, likely poor nutrition, missed exercise, a whole lot of things happening to new fathers that can lower measured serum testosterone. Whether or not it matters is an entirely different matter. Headline bloodwork numbers don't mean much out of context, and most of the outcomes you'd actually care about (athletic performance, muscle retention, general feeling of wellbeing and energy level) are all impacted by the same things whether or not testosterone is lowered. The one thing that might matter separately is sperm production, but if you care about being maximally able to get your wife pregnant again immediately after she gives birth, you can get that tested separately.

[djtango]

I can't really refute this but I suspect based on the body of research on this study, the drop must be a lot more than just sleep deprivation. There are plenty of men who work long hours and have poor sleep but I don't believe the drop in T is as remarkable as that post partum

How about the science behind how a baby's crying stimulates milk production.

[llamaimperative]

Again cognitive.

These are only challenging you because you’re assuming cognition cannot affect hormones/chemical systems but we know otherwise.

[djtango]

Not really challenging me, I'm more marvelling at the fact that as giant bags of proteins, we're able to look at our baby and our testicles decide that it's the time to stop doing what they do most of the time.

Cognition is such a handwave IMO - what's the biochemistry behind that? What's the signalling mechanism by which our brain does that? Does that mean with the right external brain signals we can turn off T production?

The implication of cognition having control over the body, which you assert is so well known, is that if we can achieve more control over our cognition we can achieve biochemical control of our body. So the bene gesserit is less fiction than we like to think?

[disgruntledphd2]

I think that (as with many of the problems of the modern world ;P) it can all be blamed on Descartes.

The notion of dualism is profoundly problematic in a bunch of ways, but the biggest problem with it is that it created generations of scientists who ended up believing that consciousness and body experience are completely separate, which is a little ludicrous when you think about it.

[fgd135]

Is it really much different to, say, looking at food and getting hungry, or looking at someone naked and getting aroused? While these are more immediate and conscious experiences, its clear that something as simple as looking at things can affect our biochemistry.

[djtango]

I take your point - you're right maybe there isn't anything that much more different.

But it feels a lot more different because the two examples you used are very clear and direct stimulus-response pairings. See food, get hungry (and get ready to digest)

See mate, get aroused, genitals get ready.

But a hormonal response is weird because:

- you see a baby then your body makes you more nurturing

- testosterone has all kinds of health implications on a longer time frame, it affects decision making, strength, muscle growth etc etc

So the fact that the body has been preprogrammed to alter our mind when we see (our?) baby is kind of impressive. Would be interesting to know if it's all babies or just our own. Do male midwives or fathers of adopted children see the same T drop.

Not to mention that T is also such a sought after hormone that understanding (and controlling) this response could be quite helpful

[ramblenode]

> Cognition is such a handwave IMO - what's the biochemistry behind that?

Hormones are chemical messengers. They exist to relay messages between different organs and tissues. An organism is constantly sampling its environment and adjusting its internal state to optimize survival and reproduction. Within this framework, it is not at all surprising that cognition interacts with hormones; in fact, it would be kind of surprising to find a biochemical pathway that is entirely independent of cognition.

A good example is stress. For those of us in the first world, stress begins as something cognitive, but it is expressed hormonally as increased serum cortisol. All you have to do to change your hormone balance is start ruminating!

Another example is oxytocin. If another human touches you affectionately, you'll see a bump in serum oxytocin. But it depends on your judgment of how affectionate the contact is, which is cognitive.

[djtango]

I appreciate your response here but it's still pretty handwavy.

Ultimately it's pretty easy to sit back and say - well it's just so. Sure we have a flight or fight and pathways towards adrenaline and cortisol. We also have pathways for oxytocin so we like to find a friend/mate. So obviously we'd also have pathways towards wanting to nurture our kids. That's evolution bro - I guess nature and science are pretty obvious and boring after all /s

The response to children is impressive to me because it appears to be highly specific in its stimulus and the ramifications are pretty large.

Our cortisol and adrenaline response is very generic. All kinds of things can trigger it. You can experience adrenaline by jumping out of a plane or gambling at a roulette table. Even in a showdown in poker or playing video games. So the same response has been conditioned towards all kinds of situations when originally it might have been predominantly towards enemies/predators

Likewise for oxytocin we can probably produce oxytocin from cuddling a pet so it's kind of generic in stimulus.

Meanwhile there's a whole slew of specific responses that men and women have towards babies that I personally find fascinating in their specificity. Maybe because I'm just ignorant but I'm excited for the future when we may be able to understand how a bunch of senses (visual, aural, olfactory) convert into specific neural signals which the body is preprogrammed (how?) to then produce a specific response (via what biochemical pathways) to induce a hormonal response. Which incidentally have pretty wide ranging physiological consequences in the case of testosterone.

[borski]

“Mind over matter” is not a colloquialism for no reason. It doesn’t work all the time, but to say it never does is a mistake.

[edmundsauto]

I’m unsure why the downvotes, but it would be an interesting study whether there is an adaptation for lower testosterone to encourage fathers to be more nurturing and less aggressive to their offspring. Ie, is there a plausible and measurable explanation for why the t-drop is evolutionarily advantageous.

[djtango]

Who knows. I did a postgrad in medicinal chemistry and I was always amazed at how we scaled up from tiny molecules/proteins into this crazy emergent system. Yet at the individual molecule level there was still so much we couldn't understand from a holistic first principles point of view.

At the time IIRC computer simulations would struggle to model like more 12 water molecules solvating something accurately.

So building up from that atomic level up to proteins into a full physiological system always seemed like magic to me and it's always felt like we didn't really know anything.

Coming back to the t response it would be interesting to know if anything else accidentally triggers it. Eg is it just babies that triggers the response? Only our baby? What about adopted babies or babies of family members? Can other cute things trigger it?

[BurningFrog]

This seems very much like a mechanism that would be favored by evolution, not an accident of circumstance.

I have no clue how that mechanism migh operate, of course. I realize that makes this comment less persuasive, but so be it.

[djtango]

The evolutionary advantage of it is fairly apparent - but understanding how we can control our own body chemistry without pharmaceutical intervention is of great interest to me.

It's a silly example but what if you could combat age onset testosterone decline with brain exercises or by watching an hour of UFC everyday. I'd take that in a heartbeat over hormone therapy if it worked

[whythre]

Pheromones from the pregnant mother seem like a good candidate for the reason behind Low T…

[datavirtue]

My vote as well. Proximity and "stickiness" to the mother. Likely not a thing if the father moves on to the next region/town after sireing a child. I think back to the isolated humans encountered by the British when working on their rocket programs. Basically groups of women that men moved between, impregnating. Move into a group, kill a child or two and/or fight other males, impregnate someone and move on. I overlay this behavior whenever I try to figure people out.