Excellent post—I enjoyed reading it, and find the mental framework useful!
Two comments:
In evolutionary analysis, there are challenges with properties that are mainly relevant in life-or-death situations. Many of the organisms faced with such circumstances will not survive the immediate situation, and of those left, many will not reproduce. This slows down or completely stops development of certain properties. For example, there are well-suntantiated claims for the deterioration of our immune system at old age due to this—we are no longer reproductively viable. I still think that your explanation is relevant (not all organisms won’t reproduce after these circumstances), but I think an evolutionary explanation should also take this into account.
This work is an important piece of the puzzle, but I would love to see a deeper syntesis with other components of the puzzle—decision-making under high-intensity pain, system-wide mechanisms (e.g., hormones), cellular biology connections. For example, I could give a different explanation regarding high-intensity pain—it does not give evolutionary value, but rather the cellular mechanism leading to pain is (for reasons of energy efficiency) linear with the input, leading to strong signals when there are strong inputs. This, coupled with the fact that many organisms die under such circumstances, would lead to negligible evolutionary cost of this high-affective pain.
To be clear, I tend to agree with your explanation, but I think the framework would be stronger by either dealing with these counter-arguments in future work, or acknowledging these alternatives.
Thanks, Itamar. I’m glad you found the framework useful, and thanks for laying out these concerns.
(1) On selection in life-or-death situations. I’m less convinced that life-or-death contexts should be treated as marginal for evolutionary explanation. Many such hazards (e.g. fire, severe injury, predation) recur across generations, and even small increases in the probability of rapid withdrawal and survival can be strongly selected for. In that sense, excruciating pain in these contexts looks like a straightforward case of ordinary evolutionary logic at work, rather than a special case where costs become irrelevant or selection effectively “switches off.”
(2) On alternative mechanisms (linear transduction, hormones, etc.). I’m very sympathetic to the idea of carefully considering non-adaptive explanations, since some features can indeed arise as byproducts of other selective pressures. I was an avid reader of Stephen Jay Gould, and The Spandrels of San Marco remains a classic reminder of this point. So I agree that high-intensity pain could arise largely as a byproduct of how damage signals scale at the sensory or cellular level, rather than because intensity itself was directly selected for. At the same time, this kind of “linear transduction” may itself carry adaptive value (i.e. function as an exaptation, again in Gould’s sense), since greater damage would naturally call for more urgent behavioral responses to stop it.
On the point about hormones or other system-wide mechanisms, I may be missing what you have in mind — I’d be very interested in a concrete example and in how you think it would change the cost–benefit picture.
Excellent post—I enjoyed reading it, and find the mental framework useful!
Two comments:
In evolutionary analysis, there are challenges with properties that are mainly relevant in life-or-death situations. Many of the organisms faced with such circumstances will not survive the immediate situation, and of those left, many will not reproduce. This slows down or completely stops development of certain properties. For example, there are well-suntantiated claims for the deterioration of our immune system at old age due to this—we are no longer reproductively viable. I still think that your explanation is relevant (not all organisms won’t reproduce after these circumstances), but I think an evolutionary explanation should also take this into account.
This work is an important piece of the puzzle, but I would love to see a deeper syntesis with other components of the puzzle—decision-making under high-intensity pain, system-wide mechanisms (e.g., hormones), cellular biology connections. For example, I could give a different explanation regarding high-intensity pain—it does not give evolutionary value, but rather the cellular mechanism leading to pain is (for reasons of energy efficiency) linear with the input, leading to strong signals when there are strong inputs. This, coupled with the fact that many organisms die under such circumstances, would lead to negligible evolutionary cost of this high-affective pain.
To be clear, I tend to agree with your explanation, but I think the framework would be stronger by either dealing with these counter-arguments in future work, or acknowledging these alternatives.
Thanks, Itamar. I’m glad you found the framework useful, and thanks for laying out these concerns.
(1) On selection in life-or-death situations.
I’m less convinced that life-or-death contexts should be treated as marginal for evolutionary explanation. Many such hazards (e.g. fire, severe injury, predation) recur across generations, and even small increases in the probability of rapid withdrawal and survival can be strongly selected for. In that sense, excruciating pain in these contexts looks like a straightforward case of ordinary evolutionary logic at work, rather than a special case where costs become irrelevant or selection effectively “switches off.”
(2) On alternative mechanisms (linear transduction, hormones, etc.).
I’m very sympathetic to the idea of carefully considering non-adaptive explanations, since some features can indeed arise as byproducts of other selective pressures. I was an avid reader of Stephen Jay Gould, and The Spandrels of San Marco remains a classic reminder of this point. So I agree that high-intensity pain could arise largely as a byproduct of how damage signals scale at the sensory or cellular level, rather than because intensity itself was directly selected for. At the same time, this kind of “linear transduction” may itself carry adaptive value (i.e. function as an exaptation, again in Gould’s sense), since greater damage would naturally call for more urgent behavioral responses to stop it.
On the point about hormones or other system-wide mechanisms, I may be missing what you have in mind — I’d be very interested in a concrete example and in how you think it would change the cost–benefit picture.