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This is exactly what you'd expect if the hypothesis that depression is an evolved adaptation for surviving no-win scenarios that can only be waited out holds.

This is exactly what you'd expect if the hypothesis that depression is an evolved adaptation for surviving no-win scenarios that can only be waited out holds. In a scenario where a disaster has negatively affected the primary productivity of the local food web (e.g. volcano, forest fire, bolide, plague or tsunami), the groups of social species that exist in an environment are likely to engage in internal strife until the food web productivity the group subsists on has returned to normality. Phenotypes which reduce activity across the board without making any changes to their distribution of activities, just hoping for things to get better on their own, are likely the phenotypes that are most successful at surviving to reproduce within conditions of intragroup strife when these infrequent disasters occur. If this line of reasoning bears out to correctly describe the actual selection pressures that have led to the genes for depression evolving, it follows that what we call major depressive disorder is in fact the genome seeing and carrying out false positives for needing the famine-survival strategy. . Incidentally, I first came across the theory I'm repeating here on Steven Byrne's neuroscience blog, if you want an avenue for finding sources.

SamoyedFurFluff 1y ago
Context: I dabbled in evolutionary biology at the university level, not enough for even a minor in the subject. My understanding is the existence of selection does not necessarily mean every trait that exists right now has an evolutionary benefit. It is more coarse grained that anything that doesn’t prevent you from breeding is acceptable. Depressed people are not made infertile by their depression, so there will be a subset of depressed people (assuming depression even has a hereditary component). This doesn’t mean the trait of depression has an advantage in order to exist, it just isn’t so much of a disadvantage that it doesn’t exist.
andoando 1y ago
There is nothing about evolutionary theory that posits that all current biological structures/functions must have a evolutionary purpose. Only the system as a whole must carry superior fitness, not each of its individual components. Given a sufficiently complex system, its rather expected that there will be negative, or even outright destructive functions that arise. You can certainly try to find a positive reason for why cancer, disease, death during conception, etc exist, but there is a much simpler explanation. Depression in this view, isn't something outright that was adaptively constructed, but merely a side effect of how the mind works.
- mothballed 1y ago
  I've often wondered if depression is exactly that, a system level optimization. Sometimes depression just happens, but sometimes it is triggered by low social status, realizing you've hurt someone in an unjustified or accidental way, having other mental illness, being seriously injured, or some other way that threatens the fitness of the overall group. Depression might be a (albeit flawed) system level way of reducing the amount of physical and social resources those people consume so that the non-depressed strata of society can better take them. Note: this is a speculation, not assertions of fact
  - Filligree 1y ago
    You’re proposing group selection, which always never happens. Evolution functions not at the level of groups, or even individuals, but genes inside of individuals. Most of the time thinking of it as group selection at the genetic level (=individuals) does work, fortunately.
    - mothballed 1y ago
      I believe it would also apply similarly under kin selection.
    - andoando 1y ago
      It makes technical sense that if one individual helped for example to make the rest of the colony propgate 3x faster, it would be a collective reproductive advantage
  - andoando 1y ago
    I think its just a natural consequence of our mind working on a positive-negative reward system, which I think its critical to any intelligence. Being manically positive is just as detrimental as being chronically depressed. Its entirely normal to be negative, or to ignore stimuli, or decide not to do things. In some situations, say if you were trapped in a cage your whole life, you'd agree it'd be entirely normal to be depressed. It would make no sense to waste energy running around hitting iron bars that won't break. In this sense, depression is somewhat of a social construct. We determine someone is depressed because we believe their reaction to the environment to not be normal.
schmidtleonard 1y ago
"Depression stops ant whorls" is my favorite quick and snappy summary.
munificent 1y ago
I do like evolutionary explanations for a lot of human behavior, but this one feels a little too pat to me. Patience, "biding our time", "hunkering down", etc. are actual emotional states we can experience and recognize, and depression doesn't feel even remotely like for most people as far as I'm aware. Also, this explanation would only really work if the entire group entered a dormant depressed state together. Otherwise, the non-depressed ones would capitalize the tribe's resource and everyone would still end up screwed. But depression doesn't seem to have that sort contagious social component. On the contrary, when someone is depressed, the immediate response by people around them is generally try to "cheer them up" or encourage them to exit that depressed state. And while the depressed person is likely conveying a whole lot of negative sentiment, most aren't actively attempting to get the people around them to be depressed too. That's the last thing most depressed people want.
- deleted 1y ago
  [deleted]
- bawolff 1y ago
  > On the contrary, when someone is depressed, the immediate response by people around them is generally try to "cheer them up" or encourage them to exit that depressed state. True, but that is when times are generally good. I doubt people would be "cheer up" in an actual disaster situation. From what i understand depressed people generally do well in disaster situations because they can still focus on critical tasks without getting overwhelmed by all the other bad stuff going on that isn't an immediate problem. (Possibly that's just a popular conception from movies. No idea if its true)
  - watwut 1y ago
    It is from the movies. Depressed people in disaster situations dont act and frustrated their close ones by being additional burden. Disaster does not cure depression, the issue is still there, just with worst consequences.
- sfink 1y ago
  > I do like evolutionary explanations for a lot of human behavior, but this one feels a little too pat to me. I agree. > Patience, "biding our time", "hunkering down", etc. are actual emotional states we can experience and recognize, and depression doesn't feel even remotely like for most people as far as I'm aware. But I don't think that's a valid counterargument. Depression doesn't need to feel like that or be motivated by that in order to be selected for. As long as it has the same effect as someone actively choosing to reduce consumption, the argument works. (Again, I'm still skeptical of the argument.) > Also, this explanation would only really work if the entire group entered a dormant depressed state together. That's valid, though to salvage the argument, you could say it applies to situations where active behavior turns out to be maladaptive. Perhaps fleeing the volcano causes you to inhale more gases and definitely die/fail to reproduce, whereas moping in place gives you a chance to luck out and be in the right place at the right times and thereby survive. That's a stretch, but the other examples are better: maybe the active people compete and kill each other off. Or the active people catch the plague while trying to help out. Actively avoiding harm might even be the better approach 99% of the time, and yet the 1% where inaction is better means that the trait can survive. Say everyone has an innate x% chance of being active. Event 1: 60% of active people survive, 40% of inactive do. Repeat several times. Event N: the soldiers find and kill 100% of active people and 75% of inactive. The survivors will not have x=100. Related example: dinosaurs and small mammals. Big things did really well until they didn't.
deleted 1y ago
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crmd 1y ago
This fits exactly with how depression feels to me, and appears to manifest itself in me behavior-wise, according to my partner. Def going to give this some thought. Thanks!
- wizzwizz4 1y ago
  Elsewhere in the thread, people disagree. +1 to the reasons I suspect that what we call "depression" is actually several different things.
  - cestith 1y ago
    I can imagine a great many things we collapse to one term because of similarities are in fact distinct, from myriad causes. Cancer is an example. The common cold is diagnosed based on symptoms, but is a reaction to any of several kinds of virus. Hell, a crab or a tree is not one class of things, but many that converged on common solutions. There’s an ADHD specialist, a neurologist, who wrote a book called “ADHD Does Not Exist”. His core argument is that ADHD is not a single disorder but a collection of symptoms that cluster together from many different underlying causes. https://isbn.nu/9780062266743 https://isbn.nu/9780062266743
JumpCrisscross 1y ago
> the hypothesis that depression is an evolved adaptation for surviving no-win scenarios that can only be waited out holds I remember from my days studying to be an actuary that the population that can best estimate mortality odds from the gut are actually the depressed. (Most of us tend to be way too optimistic about common risks and pessimistic about uncommon ones.) This was also used to explain mammalian postpartum depression, when the mother has to make a wretching call as to whether to keep the offspring given its health, her health and the environmental context.
cheesecompiler 1y ago
depression, like alcoholism, is a crutch and a symptom of a deeper issue, not an independent behaviour in a vacuum.

SamoyedFurFluff 1y ago

Context: I dabbled in evolutionary biology at the university level, not enough for even a minor in the subject. My understanding is the existence of selection does not necessarily mean every trait that exists right now has an evolutionary benefit. It is more coarse grained that anything that doesn’t prevent you from breeding is acceptable. Depressed people are not made infertile by their depression, so there will be a subset of depressed people (assuming depression even has a hereditary component). This doesn’t mean the trait of depression has an advantage in order to exist, it just isn’t so much of a disadvantage that it doesn’t exist.

andoando 1y ago

There is nothing about evolutionary theory that posits that all current biological structures/functions must have a evolutionary purpose. Only the system as a whole must carry superior fitness, not each of its individual components. Given a sufficiently complex system, its rather expected that there will be negative, or even outright destructive functions that arise. You can certainly try to find a positive reason for why cancer, disease, death during conception, etc exist, but there is a much simpler explanation. Depression in this view, isn't something outright that was adaptively constructed, but merely a side effect of how the mind works.

mothballed 1y ago
I've often wondered if depression is exactly that, a system level optimization. Sometimes depression just happens, but sometimes it is triggered by low social status, realizing you've hurt someone in an unjustified or accidental way, having other mental illness, being seriously injured, or some other way that threatens the fitness of the overall group. Depression might be a (albeit flawed) system level way of reducing the amount of physical and social resources those people consume so that the non-depressed strata of society can better take them. Note: this is a speculation, not assertions of fact
- Filligree 1y ago
  You’re proposing group selection, which always never happens. Evolution functions not at the level of groups, or even individuals, but genes inside of individuals. Most of the time thinking of it as group selection at the genetic level (=individuals) does work, fortunately.
  - mothballed 1y ago
    I believe it would also apply similarly under kin selection.
  - andoando 1y ago
    It makes technical sense that if one individual helped for example to make the rest of the colony propgate 3x faster, it would be a collective reproductive advantage
- andoando 1y ago
  I think its just a natural consequence of our mind working on a positive-negative reward system, which I think its critical to any intelligence. Being manically positive is just as detrimental as being chronically depressed. Its entirely normal to be negative, or to ignore stimuli, or decide not to do things. In some situations, say if you were trapped in a cage your whole life, you'd agree it'd be entirely normal to be depressed. It would make no sense to waste energy running around hitting iron bars that won't break. In this sense, depression is somewhat of a social construct. We determine someone is depressed because we believe their reaction to the environment to not be normal.

schmidtleonard 1y ago

"Depression stops ant whorls" is my favorite quick and snappy summary.

munificent 1y ago

I do like evolutionary explanations for a lot of human behavior, but this one feels a little too pat to me. Patience, "biding our time", "hunkering down", etc. are actual emotional states we can experience and recognize, and depression doesn't feel even remotely like for most people as far as I'm aware. Also, this explanation would only really work if the entire group entered a dormant depressed state together. Otherwise, the non-depressed ones would capitalize the tribe's resource and everyone would still end up screwed. But depression doesn't seem to have that sort contagious social component. On the contrary, when someone is depressed, the immediate response by people around them is generally try to "cheer them up" or encourage them to exit that depressed state. And while the depressed person is likely conveying a whole lot of negative sentiment, most aren't actively attempting to get the people around them to be depressed too. That's the last thing most depressed people want.

deleted 1y ago
[deleted]
bawolff 1y ago
> On the contrary, when someone is depressed, the immediate response by people around them is generally try to "cheer them up" or encourage them to exit that depressed state. True, but that is when times are generally good. I doubt people would be "cheer up" in an actual disaster situation. From what i understand depressed people generally do well in disaster situations because they can still focus on critical tasks without getting overwhelmed by all the other bad stuff going on that isn't an immediate problem. (Possibly that's just a popular conception from movies. No idea if its true)
- watwut 1y ago
  It is from the movies. Depressed people in disaster situations dont act and frustrated their close ones by being additional burden. Disaster does not cure depression, the issue is still there, just with worst consequences.
sfink 1y ago
> I do like evolutionary explanations for a lot of human behavior, but this one feels a little too pat to me. I agree. > Patience, "biding our time", "hunkering down", etc. are actual emotional states we can experience and recognize, and depression doesn't feel even remotely like for most people as far as I'm aware. But I don't think that's a valid counterargument. Depression doesn't need to feel like that or be motivated by that in order to be selected for. As long as it has the same effect as someone actively choosing to reduce consumption, the argument works. (Again, I'm still skeptical of the argument.) > Also, this explanation would only really work if the entire group entered a dormant depressed state together. That's valid, though to salvage the argument, you could say it applies to situations where active behavior turns out to be maladaptive. Perhaps fleeing the volcano causes you to inhale more gases and definitely die/fail to reproduce, whereas moping in place gives you a chance to luck out and be in the right place at the right times and thereby survive. That's a stretch, but the other examples are better: maybe the active people compete and kill each other off. Or the active people catch the plague while trying to help out. Actively avoiding harm might even be the better approach 99% of the time, and yet the 1% where inaction is better means that the trait can survive. Say everyone has an innate x% chance of being active. Event 1: 60% of active people survive, 40% of inactive do. Repeat several times. Event N: the soldiers find and kill 100% of active people and 75% of inactive. The survivors will not have x=100. Related example: dinosaurs and small mammals. Big things did really well until they didn't.

deleted 1y ago

[deleted]

crmd 1y ago

This fits exactly with how depression feels to me, and appears to manifest itself in me behavior-wise, according to my partner. Def going to give this some thought. Thanks!

wizzwizz4 1y ago
Elsewhere in the thread, people disagree. +1 to the reasons I suspect that what we call "depression" is actually several different things.
- cestith 1y ago
  I can imagine a great many things we collapse to one term because of similarities are in fact distinct, from myriad causes. Cancer is an example. The common cold is diagnosed based on symptoms, but is a reaction to any of several kinds of virus. Hell, a crab or a tree is not one class of things, but many that converged on common solutions. There’s an ADHD specialist, a neurologist, who wrote a book called “ADHD Does Not Exist”. His core argument is that ADHD is not a single disorder but a collection of symptoms that cluster together from many different underlying causes. https://isbn.nu/9780062266743 https://isbn.nu/9780062266743

JumpCrisscross 1y ago

> the hypothesis that depression is an evolved adaptation for surviving no-win scenarios that can only be waited out holds I remember from my days studying to be an actuary that the population that can best estimate mortality odds from the gut are actually the depressed. (Most of us tend to be way too optimistic about common risks and pessimistic about uncommon ones.) This was also used to explain mammalian postpartum depression, when the mother has to make a wretching call as to whether to keep the offspring given its health, her health and the environmental context.

cheesecompiler 1y ago

depression, like alcoholism, is a crutch and a symptom of a deeper issue, not an independent behaviour in a vacuum.