Breast-sleeping
Updated: Mar 17
Breast-sleeping is the evolutionary norm.
Solitary infant sleep was only introduced by a couple of male "experts" just a little over 100yrs ago.

That's when baby "sleep problems" became a thing, and people tried to solve how to "train" babies to sleep alone - something that was never the evolutionary norm. We started to mess with nature, without any evidence that it wouldn't cause any harm.
This is an excellent paper to understand the topic more and to question if it's really a smart idea to go against thousands of years of evolution, and instead base your baby sleep choice in a very recent "trend", which has not yet had enough time to see how it turns out in the context of evolution and natural selection.
We do know that breast-sleeping led to the continuation of our species.
We have no evidence that solitary sleeping of our infants will.. because not enough time has lapsed.
I personally think that, in time, we will discover a link between solitary sleeping and abnormal psychology i.e. personality disorders like Narcissistic Personality Disorder, Borderline Personality Disorder, Psychopathy and Sociopathy.
And when we become a species with an increasing prevalence of those abnormal psychology profiles... well, you're looking at not a tribe of humans, but individual self-gods / self-tribes (i.e. one person is one tribe, everyone is out for themselves, we are no longer prosocial and collaborative... instead we will all be at war with each other… which pretty much spells the end of humans, as a society of only sociopaths is a bloodbath).
The highest level of evolution in humans is the ability to experience "shame" - and sociopaths don’t have shame, so it’s taking humans not in the direction of evolution… but the other way.
And, you can see that in the first cohort of babies that went through ferberising... it's become mainstream to speak of narcissistic mothers who don't even have the instinct to be nurturing to their own babies and instead have no empathy for them, instead feeling entitled to the babies meeting the mothers needs and making the mother happy... which is definitely not the evolutionary role of a mother which was meant to protect and nourish her offspring.
Might seem extreme, but when you mess with nature and interfere with our evolutionary development at such a young age with no evidence as to what the long term impacts might be, well, nothing is guaranteed.
Here is a paper to find out more on the topic (and to realise that just because all your mates use cots and solitary sleeping, and just cause some fancy influencer on social media does it... doesn't mean it's safe and evolutionarily appropriate for humans... just like smoking didn't turn out to be safe even though all the movies stars were doing it).
It's influencers against evolution.
Hopefully, for the future of our species sake... people will consider evolution to be of more importance than assimilating to an uneducated, tribe following a recent trend:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6866223/
