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Here is compilation of the most recent contributions to conclude the debate on depression and adaptation: 1. Mike Waller 2. Mike Waller 3. Alex. A.B. 4. Gregg Henriques 5. Alex. A.B. 6. Graham D. Richards 7. Paul Barrett 8. Gregg Henriques From: "Mike Waller" <M.Waller@stigma.freeserve.co.uk> To: <mgoldh@well.com>, <evolutionary-psychology@egroups.com> Subject: Re: [evol-psych] Re: Is Depression an Adaptation? Date: Tue, 25 Jan 2000 19:23:33 -0000 From: Michael Goldhaber <mgoldh@well.com> > As I understand him, Waller suggests that a tendency to depression would enhance the > adaptive fitness of the depressive's kin, if both might carry genes that would be > undesirable to potential mates of the non-depressive kin of the depressive. These could > hardly be genes for depression, since in that case the depressive'spresence would have > the opposite of the proposed effect. So, Waller must be suggesting that depression is an > evolution-favored response to having non-desirable traits. My basic point is that we all carry the potential for disabling and lethal depression; but that its actualisation is contingent on our being made to feel that we are in some way surplus to requirements. This is why the incidence is so high amongst the unemployed and the divorced. It is not selected out simply because families which have this mechanism of membership regulation out-evolve families which do not. > Is there any evidence that depression is so distributed? I very much doubt it. Certainly > among humans, there are many with severe problems of genetic or non-genetic origin alike > who are so upbeat as to inspire the (nearly) perfectly healthy. The issue is not how you are objectively, but how you are made to feel. Obviously your own emotional robustness comes into this, but with my model an individual who is seriously disadvantaged from a biological perspective yet nonetheless loved and cherished by key care-givers has a major edge over somebody less biologically disadvantaged but nonetheless made by others to feel themselves as being without or of little value . Mike _______ From: "Mike Waller" <M.Waller@stigma.freeserve.co.uk> To: "Alex. A.B." <stenomicra@hotmail.com>, <evolutionary-psychology@eGroups.com> Subject: Re: [evol-psych] Re: Is Depression an Adaptation? Date: Tue, 25 Jan 2000 20:01:16 -0000 > In consequence a mechanism which,when triggered by a strong sense of > failure, starts with profound depression and then moves on to > self-elimination would have clear inclusive fitness benefits. Obviously the > low frequency of suicide makes it an unlikely bedrock of this process; but > the great range of life-shortening physiological effects now known to be > associated with chronic depression very much fit the bill.> > > How do you imagine a trait that leads to self-elimination being selected for > in a population and passed along? > > See, the people which have the trait but do not express it, reproduce and > leave offspring. For them, the trait is neutral, right? So, the trait is not > subjected to positive selection. > > Those in which the trait is expressed, have poorer fitness, die early, kill > themselves. The trait is adaptive to the population, according to you, but > its ability to be passed along is poor, right? > > A trait which is either neutral, or decreases the individual's ability to > leave viable offspring, is exactly the contrary of what we usually mean by > "adaptive". Just because I came to it first in my in-tray, I have already answered this in another post. To re-iterate, my theory is grounded in Hamilton's inclusive fitness theory i.e. individuals will be sacrificed when the probable consequence of their sacrifice is that more successful copies of the gene(s) responsible get through than would otherwise be the case. Hamilton has already suggested that a non-viable embryo or neonate ought to self-destruct, sensing in some way that resources expended on it could be put to better effect if switched to kin. I make the same argument in respect of healthy young who, in times of resource scarcity "do the decent thing" rather than squabble for scraps with marginally fitter siblings. In both cases you will appreciate that, not withstanding the loss of the self-sacrificing individuals, families in which all members carry contingent self-sacrifice genes, out-compete ones in which disputatious individuals refuse to accept evolution's short straw. In my view depression is the perfect vehicle from achieving such effects. Strictly speaking, other than for the final comment about depression, the above is non-controversial. My big step is to argue that the same principle could also be applied to mature adults in the context of sexual selection. Goffman called it "tribal stigma", others "associative stigma", but whatever it is called, the general principle is that out socio-sexual reputations can be severely damaged in consequence of mal-adaptiveness expressed in close kin. Ergo, there must come a point at which, just like the non-viable neonate, kin selection advantage must lie with the individual perceived to be causing the stigma self-eliminating. And that is where I imagine the depression led mechanism to kick in. Mike ______ From: "Alex. A.B." <stenomicra@hotmail.com> To: evolutionary-psychology@eGroups.com Subject: Re: [evol-psych] Re: Is Depression an Adaptation? Date: Tue, 25 Jan 2000 20:11:43 GMT <These could hardly be genes for depression, since in that case the depressive's presence would have the opposite of the proposed effect. So, Waller must be suggesting that depression is an evolution-favored response to having non-desirable traits> You got it. His reply, invoking mate selection (or the reverse of it), only sustains the same argument. Adaptive traits are usually though of in terms of enhancing fitness. They are selected for and are passed along Non-adaptive traits are thought to have the opposite effect, they reduce fitness and are eliminated from a population. What has been claimed by him, among other things, is that the elimination of a deleterious trait is adaptive for a species. The other argument implied in his message is that Mate Selection (and he makes an analogy with the "runaway theory" for mate selection) would somehow speed up the elimination of the undesirable trait. I do not like his theory very much because it is superfluous. Elimination of poor fitted organisms is already one prediction of the natural selection theory. But I like the fact that on the background, his message is in agreement with my own theory that depression is not an adaptation. Alex. ______ From: Coachhenri@aol.com To: stenomicra@hotmail.com, FHSDM@aol.com, evolutionary-psychology@egroups.com Subject: Re: [evol-psych] Testing of adaptive hypothesis Date: Tue, 25 Jan 2000 17:30:15 EST Alex, I don't think I agree with your assessment here. I don't think I ever referred to depression as currently being adaptive. If you read my earlier postings I explicitly stated that depression may not be adaptive and may very well be an example of a mismatch between our evolutionary heritage and our present situation. Indeed, the presumed historical context of more danger and lesser control over the environment is crucial to the model that I was advocating. Regards, Gregg H In a message dated 1/25/00 2:12:18 PM Eastern Standard Time, stenomicra@hotmail.com writes: << An adaptionist interpretation cannot be made as an ahistorical interpretation of a function of a feature or a trait that has an effect on current fitness, otherwise the term adaptation becomes a synonym of that word (function). The message written by Dr. Gregg Henriques , for example, embodies this element of circularity. He defines depression in terms of its function (energy conservation) and uses in turn energy conservation as the main prediction of his theory. Note here that the interpretation is ahistorical, and employs an explanation of function on current fitness as a phenotipic acomodation to stress. >> ______ From: "Alex. A.B." <stenomicra@hotmail.com> To: Coachhenri@aol.com, evolutionary-psychology@eGroups.com Subject: Re: [evol-psych] Testing of adaptive hypothesis Date: Tue, 25 Jan 2000 23:29:08 GMT Dr. Gregg, If I made this mistake, I apologize. I mean, I apologize that I have made this mistake. However, my observation still holds once you stated that depression was adaptive at some past time in the history of our species, and I think you did. I briefly quote you: "because of the lesser control and greater danger, the propensity to shut down in unpropitious situations may very well have been adaptive in the EEA, but not adaptive now". Not that I am certain that depression wasn't ever adaptive. I do not know. My point is the circular element of your theory, which makes it difficult to test. I would like you to comment on that, if possible. The historical contend I was referring to explicitly means "evolutionary history". As I recall, the predictions of your hypothesis all refer either to causal triggers of depression (the first set of predictions), or to consequences such as "energy conservation" or "decrease in behavioral output" (second set of predictions). You are making predictions about the phenotypic expression of a trait when the organism is under stress, and that is all you are doing. There is no evolutionary (historical) argument here, or any test for it. Somewhere earlier in your text, however, you had said that depression is "an evolved propensity TO decrease behavioral output". This is an adaptive argument with a historical component, and there are some ways to test for it. But your argumentation does not address this issue in a proper way. I mean, in a way proper for the (evolutive) level you are employing. Otherwise I have found your posting very interesting and well-articulated, and I did not mean to criticize it. I was just mentioning what I thought was (and I still think it is) a good example of an "ahistorical interpretation of a function of a feature or a trait that has an effect on current fitness". Best regards Alex. ______ From: "Graham D. Richards" <G.D.Richards@staffs.ac.uk> To: "Alex. A.B." <stenomicra@hotmail.com> Cc: FHSDM@aol.com, evolutionary-psychology@eGroups.com Subject: Re: [evol-psych] Testing of adaptive hypothesis Date: Wed, 26 Jan 2000 10:01:55 +0000 This might be a naive point, but surely at any given point in time we would expect there to be some non-adaptive features around which are in the process of being selected out? If so, demonstrating the non-adaptiveness of a trait would prove nothing about the validity or otherwise of adaptationism/ natural selection in general? Indeed, if we couldn't find such non-adaptive traits this would actually raise more doubts than if we could. Have I misunderstood something here? Graham Richards _______ From: Mike Waller <M.Waller@stigma.freeserve.co.uk> To: Paul Barrett <p.barrett@liverpool.ac.uk>; <evolutionary-psychology@egroups.com> Sent: Tuesday, January 25, 2000 5:53 PM Subject: [evol-psych] Re: Is Depression an Adaptation? Hello Mike I'll get my admin to chase down the bulletin from the WHO - and let you have a copy etc. if succesful! Many thanks for the reference. > If you consider evolutionary explanations superfluous, what attractions does > an evolutionary psychology list have for you? I am a scientist. The explanatory framework of Darwinian evolution, along with the concept of adaptation, genetic algorithms, and artificial life, are key fields that have some considerable bearing on the greater understanding of human behaviour and psychology. I happen to feel that evolutionary psychology is too broad and global in its explanatory statements (almost literary in its breadth - akin to some kinds of social psychology) - but, learning is a continual process - so I sit and read everything that appears on this list - try to evaluate it within my own philosophical and quantitative scientific constraints, then, where mismatches occur, probe the list for some answers/responses in order that I might better understand the mismatch, and/or modify my own thinking and philosophy accordingly. As to whether evolutionary explanations are superfluous - well, yes and no. It seems to me to depend upon the level of description one wishes to put forward to explain behaviours or cognitions. Again, this is reminding me more and more of social psychology and the role of individual differences parameters within a sociologically based "explanation" of behaviour. Perhaps I am betraying a predilection to try and understand more precisely some "here and now" processes rather than focussing on "how did they get there". For me, there is no point trying to answer the latter until you have better understood/measured the former. However, my personal views are irrelevant to the list - but I thought that I would take a little space to answer your question (in case there are others like me on the list who might also have had some initial difficulty in formulating an answer!). Regards .. Paul _____________________________________________________________________ Paul Barrett Direct Tel: (44)-1555-841343 email: p.barrett@liv.ac.uk Hospital Tel: (44)-1555-840293 CS2000: pbarrettx1@cs.com Fax: (44)-1555-840024 http://www.liv.ac.uk/~pbarrett/paulhome.htm Chief Scientist, The State Hospital, Carstairs, Scotland, ML11 8RP, UK Senior Research Fellow, Clinical Psychology, Liverpool University, UK _______ From: Coachhenri@aol.com 6:07 AM Tue 26 Jan Michael W. I disagree with your analysis for many different reasons and not because it is an unpleasant portrait of the human condition. First off, there is a parsimonious and straight-forward explanation for why depression, particularly chronic depression, is associated with a decrease in life span- depressed organisms are stressed organisms. As has long been known by physiologists and health psychologists, stress results in the production of hormones that alter metabolic rates. This change in metabolism results in short term gain, but comes with long term costs, such as problems with immunology. Second, what is your evidence that "depressed people are markedly less well adapted" to solve problems in the EEA. You state with seeming absolute confidence that the "slow down in locomotion" would be a death sentence. I need evidence for this. It seems to me not going out on a hunt or not actively engaging in a war or shutting down when being controlled by others are potentially beneficial responses when things are not going well. Third, what data do you have that hunter-gatherers would be less likely to choose a mate because their siblings were depressed? And, can you document that this is SUCH A STRONG SELECTION PRESSURE that it is more advantageous for the depressed person's genes to have a self-destruct mechanism? This seems outrageous to me! Fourth, it seems to me that depressed individuals frequently receive help from their kin. This seems to directly contradict your proposal. Fifth, what predictions does your model make that can be explored? For example, does your model predict that only children would not get depressed? It seems to me that if you are supporting a self-destruct model that benefits kin, only children should be much less likely to become depressed. Sincerely, Gregg H. (from peter.kabai@gmail.com) |
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