Given my own experience with depression, it makes some amount of intuitive sense. For me at least, "sadness" is not wrong, but other than that it doesn't describe the experience very well at all.
When I'm really down, I can't bring myself to care about "aversive events". I might even welcome them a little bit, both because they fit my understanding better (everything is proceeding as it should be, this ant eating my flesh makes sense) and because it's an opportunity to feel something at least. For me anyway, depression is more about absence of affect than feeling "sad", and ironically it is maddening (and yet, in a sense I can't bring myself to care.)
Then again, my explanation suggests that depressed people ought to be better at avoiding harm through inaction, and I didn't see that in the abstract?
Another hypothesis is that you could stop at "Depression Reduces Capacity to Learn". It feels like all mental processing is muted, and especially any forms of change. I guess you could do a study where you have to learn to actively prevent an aversive event for someone else. But the 1st hypothesis may still apply: depressed people may still care less about harm to someone else (than if they were not depressed). But at least you could separate out whether it's only because depressed people don't care what happens to themselves.
I experience depression as an autonomous shutdown, under great mental weight.
The ability to make any mental and physical effort is greatly reduced to "depressed" levels.
It is the subconscious version of a situation where you need to climb out of a pit, but the walls are perfectly flat and oiled. Even though you need to get out of the pit, instead of scrambling in an attempt, you just sit down.
The situation may not really be like that, but some deep cognitive machinery has concluded that it is.
It isn't anything like sadness. Although sadness could be part or proximate cause of a particular depressive episode, it is neither a necessary or sufficient condition.
I agree, sadness is not how I would describe depression. It's more like... a deep sense of apathy, emptiness and hopelessness with no apparent cause or end in sight.
Of course that mental state would hinder learning, you're missing all the brain signals and reward feedback to care about anything.
My personal experience is that the cost of enduring a negative stimulus is not simply a function of the magnitude of the negative stimulus, but rather the magnitude of the negative stimulus in relation to the magnitude of all other concurrent negative stimuli. This study controls the environment so that a single negative stimulus is isolated and additional external negative stimuli are minimized, but it cannot control for the fact that a depressed person also endures a constant barrage of negative stimuli which are generated internally (hopelessness, exhaustion, fear, self-doubt, etc). The magnitude of these internally generated negative stimuli is likely much larger than that of the aversive external stimulus used in this study, so it seems reasonable that the marginal relief obtained by avoiding the external stimulus may be perceived as relatively negligible, or at least diminished to the point that the cost of avoiding is greater than the cost of enduring.
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.
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.
> 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.
> 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)
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.
My understanding of the "modern" point of view is that selection acting at the level of the gene (not the organism or group) is sufficient as a theory. The Selfish Gene and The Extended Phenotype go into this stuff in a lot of detail.
Totally agree with your first sentence though. And even if there is a plausible adaptive function it may have only been adaptive in the past, or might be a side effect of some other adaptive function (see sickle cell anemia), or a host of other possibilities.
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
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.
If the genotype is mostly 'expressed' as depression in certain scenarios that allow your kin to reproduce better at the expense of you reproducing worse, that's not necessarily true.
Imagine for a moment, a version of depression that appears after someone gets their reproductive member cut off (perhaps encounter an angry lion?), but they are still around to compete for food with the extended family's children.
The rule of thumb is if something has a cost and persists over time it must have some benefit even if we don’t understand what that is. Otherwise, creatures not paying the cost will outcompete over time.
> 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.
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.
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!
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
"These findings suggest that in young adults, depressive symptoms are associated with difficulty in overriding prepotent responses to actively avoid aversive outcomes in the absence of reward."
My word... Could they have phrased that any less clearly?
As I understand it: the more depressive symptoms the subjects showed, the less likely they were to actively avoid bad outcomes (unless there was some other associated reward).
Yep, a sentence only someone on tenure-track could love.
ChatGPT, asked to translate to a high schooler: "Basically, this study found that young people with depression sometimes struggle to break automatic habits, especially when they’re trying to avoid something bad and there isn’t a prize or reward for doing it."
> ChatGPT, asked to translate to a high schooler: "Basically, this study found that young people with depression sometimes struggle to break automatic habits, especially when they’re trying to avoid something bad and there isn’t a prize or reward for doing it."
The translation is just as much of a word salad as the original, just with simpler vocabulary. Worse, it mangles the key point.
Prepotent responses aren't "automatic habits," but overriding responses (e.g. pain) [1]. The "sometimes" qualifier is unsubstantiated when describing "association". And the struggle isn't amplified ("especially") when avoiding something bad absent reward, the first part of the sentence is conditional upon the absence of a reward. (It's nonsense to say pool drownings are especially common in pools.)
The article claimed it is a failure to learn whereas the phrasing from ChatGPT results in a much wider implication. Failure in a struggle to do something could imply a moral failure. If that's the message people get from this research, then there's a real risk it could worsen depression.
Please don't post ChatGPT slop without then going through it with a fine-toothed comb, and checking whether it's correct. (It almost never is, but the criticism can be interesting… in discussion about ChatGPT. Otherwise, it's a derail.)
For people interested in explanations of depression that's more than "It's an imbalance in brain chemistry" I recommend looking at the work of Lisa Feldman-Barrett. She explains how brains work¹ in computational & evolutionary terms & it's a lot better than the typical reductionist explanations in terms of chemical imbalances.
I suffered from depression and could not do anything for many years. I knew exactly what to do but could not put “pen to paper” and execute. Wish people took mental health more seriously and I don’t mean taking meds. Depression can reduce someone highly intelligent and functional down to absolutely nothing.
Given my own experience with depression, it makes some amount of intuitive sense. For me at least, "sadness" is not wrong, but other than that it doesn't describe the experience very well at all.
When I'm really down, I can't bring myself to care about "aversive events". I might even welcome them a little bit, both because they fit my understanding better (everything is proceeding as it should be, this ant eating my flesh makes sense) and because it's an opportunity to feel something at least. For me anyway, depression is more about absence of affect than feeling "sad", and ironically it is maddening (and yet, in a sense I can't bring myself to care.)
Then again, my explanation suggests that depressed people ought to be better at avoiding harm through inaction, and I didn't see that in the abstract?
Another hypothesis is that you could stop at "Depression Reduces Capacity to Learn". It feels like all mental processing is muted, and especially any forms of change. I guess you could do a study where you have to learn to actively prevent an aversive event for someone else. But the 1st hypothesis may still apply: depressed people may still care less about harm to someone else (than if they were not depressed). But at least you could separate out whether it's only because depressed people don't care what happens to themselves.
I experience depression as an autonomous shutdown, under great mental weight.
The ability to make any mental and physical effort is greatly reduced to "depressed" levels.
It is the subconscious version of a situation where you need to climb out of a pit, but the walls are perfectly flat and oiled. Even though you need to get out of the pit, instead of scrambling in an attempt, you just sit down.
The situation may not really be like that, but some deep cognitive machinery has concluded that it is.
It isn't anything like sadness. Although sadness could be part or proximate cause of a particular depressive episode, it is neither a necessary or sufficient condition.
I agree, sadness is not how I would describe depression. It's more like... a deep sense of apathy, emptiness and hopelessness with no apparent cause or end in sight.
Of course that mental state would hinder learning, you're missing all the brain signals and reward feedback to care about anything.
After a few months feeling well, I'm experiencing depression again and your description is very fitting.
I agree. It's not sadness, it's something gnawing your teeth in silence a.k.a. madness.
My personal experience is that the cost of enduring a negative stimulus is not simply a function of the magnitude of the negative stimulus, but rather the magnitude of the negative stimulus in relation to the magnitude of all other concurrent negative stimuli. This study controls the environment so that a single negative stimulus is isolated and additional external negative stimuli are minimized, but it cannot control for the fact that a depressed person also endures a constant barrage of negative stimuli which are generated internally (hopelessness, exhaustion, fear, self-doubt, etc). The magnitude of these internally generated negative stimuli is likely much larger than that of the aversive external stimulus used in this study, so it seems reasonable that the marginal relief obtained by avoiding the external stimulus may be perceived as relatively negligible, or at least diminished to the point that the cost of avoiding is greater than the cost of enduring.
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.
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.
> 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.
> 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)
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.
My understanding of the "modern" point of view is that selection acting at the level of the gene (not the organism or group) is sufficient as a theory. The Selfish Gene and The Extended Phenotype go into this stuff in a lot of detail.
Totally agree with your first sentence though. And even if there is a plausible adaptive function it may have only been adaptive in the past, or might be a side effect of some other adaptive function (see sickle cell anemia), or a host of other possibilities.
Why not the group?
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
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.
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.
I believe it would also apply similarly under kin selection.
Such phenotypes would fail to reproduce, leading to the genes for those phenotypes dying out.
If the genotype is mostly 'expressed' as depression in certain scenarios that allow your kin to reproduce better at the expense of you reproducing worse, that's not necessarily true.
Imagine for a moment, a version of depression that appears after someone gets their reproductive member cut off (perhaps encounter an angry lion?), but they are still around to compete for food with the extended family's children.
The rule of thumb is if something has a cost and persists over time it must have some benefit even if we don’t understand what that is. Otherwise, creatures not paying the cost will outcompete over time.
Or it’s caused by the same thing as something that does have a benefit.
> 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.
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.
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!
Elsewhere in the thread, people disagree. +1 to the reasons I suspect that what we call "depression" is actually several different things.
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
"Depression stops ant whorls" is my favorite quick and snappy summary.
"These findings suggest that in young adults, depressive symptoms are associated with difficulty in overriding prepotent responses to actively avoid aversive outcomes in the absence of reward."
My word... Could they have phrased that any less clearly?
As I understand it: the more depressive symptoms the subjects showed, the less likely they were to actively avoid bad outcomes (unless there was some other associated reward).
Yep, a sentence only someone on tenure-track could love.
ChatGPT, asked to translate to a high schooler: "Basically, this study found that young people with depression sometimes struggle to break automatic habits, especially when they’re trying to avoid something bad and there isn’t a prize or reward for doing it."
> ChatGPT, asked to translate to a high schooler: "Basically, this study found that young people with depression sometimes struggle to break automatic habits, especially when they’re trying to avoid something bad and there isn’t a prize or reward for doing it."
The translation is just as much of a word salad as the original, just with simpler vocabulary. Worse, it mangles the key point.
Prepotent responses aren't "automatic habits," but overriding responses (e.g. pain) [1]. The "sometimes" qualifier is unsubstantiated when describing "association". And the struggle isn't amplified ("especially") when avoiding something bad absent reward, the first part of the sentence is conditional upon the absence of a reward. (It's nonsense to say pool drownings are especially common in pools.)
[1] https://dictionary.apa.org/prepotent-response
> sometimes struggle to break automatic habits
The article claimed it is a failure to learn whereas the phrasing from ChatGPT results in a much wider implication. Failure in a struggle to do something could imply a moral failure. If that's the message people get from this research, then there's a real risk it could worsen depression.
Please don't post ChatGPT slop without then going through it with a fine-toothed comb, and checking whether it's correct. (It almost never is, but the criticism can be interesting… in discussion about ChatGPT. Otherwise, it's a derail.)
For people interested in explanations of depression that's more than "It's an imbalance in brain chemistry" I recommend looking at the work of Lisa Feldman-Barrett. She explains how brains work¹ in computational & evolutionary terms & it's a lot better than the typical reductionist explanations in terms of chemical imbalances.
¹https://www.youtube.com/watch?v=KliAI9umFyY
I suffered from depression and could not do anything for many years. I knew exactly what to do but could not put “pen to paper” and execute. Wish people took mental health more seriously and I don’t mean taking meds. Depression can reduce someone highly intelligent and functional down to absolutely nothing.
Hence (for example) the doom scrolling wheel keeps spinning.