Negative health outcomes are an evolutionary pressure.
Also, evolution does not work from a plan, we do not spontaneously generate all the things that would benefit us over a long enough timeframe. Instead, random things happen and certain ones propagate while others don’t. Because it is not a conscious force operating from any sort of plan, and instead works via random mutation and propagation of beneficial traits, it leaves a whole bunch of potentially beneficial things unadopted.
Otherwise all life would just move towards some sort of optimal form, maybe crabs, instead of evolving greater and greater diversity that can better handle changing environments.
AbouBenAdhem@lemmy.world 15 hours ago
Beneficial mutations are random, but the odds of them persisting are proportional to the frequency of the events in which they affect our fitness. And the proportion of stressful events in which pets were available would have been only a fraction of the total number of stressful events our ancestors experienced.
If pets are available for 10% of the stressful events we experience, the selection pressure for stress reduction that doesn’t require pets would be ten times greater.
Carrolade@lemmy.world 14 hours ago
But what is the likelihood of this autonomous stress relieving function arising, how many mutations would be required to implement such a thing? Would it have any significant drawbacks or side effects in other aspects of our biology?
You can’t look only at the propagation side of things.
Another thing, stress isn’t event based per se. It’s more of a floating value that always exists to a certain degree and provides both positive and negative effects at different levels and in different situations. The negative health impacts come in when it remains high for a long period of time. So what we’d really want to look at is something like the frequency of headpats given to your dog or something, and the effects of this compared to other potential stress relieving activities like meditation.
Lastly, I would check your data on pet availability, I think it’d be far, far higher than 10%.
AbouBenAdhem@lemmy.world 14 hours ago
Even if every human on earth had their own pet since dogs were first domesticated ten or twenty thousand years ago, their ancestors were facing the stress of migrating into new and unfamiliar environments for several hundred thousand years prior to that.
Carrolade@lemmy.world 14 hours ago
Certainly. But we still cannot say that should mean every beneficial mutation for their lives was likely to be adopted. Like I said earlier, the majority of possibly good things are left on the table, even when drawbacks are not considered.
Including drawbacks muddies it up even further, we can look at how cardiovascular shock occurs and how the particular traits that create it were a bit of a double edged sword.