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Is killing yourself adaptive? That depends: An evolutionary theory about suicide

The views expressed are those of the author and are not necessarily those of Scientific American.

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Most psychological science is the science of being and feeling like a human being, and since there is only one human being that I have or ever will have experience in being, it is not always clear to me where my career ends and my personal life begins. And this is especially salient to me right now because, like many other adult gay commentators and horrified onlookers, the raft of gay teen suicides in recent weeks has reawakened memories of my own adolescent battles with suicidal thought. There is so much I want to say about this, in fact, that I’ll be breaking this column up into two separate posts, for I’m reminded of the many illuminating theories and studies on suicide I’ve come across over the years that helped me to understand—and more importantly to overcome and to escape from—that frighteningly intoxicating desire to prematurely rid myself of a seemingly interminable hell.

If only I could have reached out and gotten hold of Tyler Clementi’s shirttail before he lunged off the George Washington Bridge, or eased my fingertips between the rope and the neck of thirteen-year-old Seth Walsh before he hanged himself from a tree in his backyard, I would have pointed out to them that, one day, they will find beauty even in this fleeting despair. I would tell them that their sexual orientation places them in the company of some of the greatest figures and secular angels in creative history—to name just a few, Michelangelo, Caravaggio, Oscar Wilde, Andy Warhol, Leonardo da Vinci, Marcel Proust, Jean Genet, Hans Christian Anderson and Tchaikovsky. Finally, I’d tell them about the scientific research and ideas that I’m going to share with you, razor-sharp reasoning by bright scholars that may have pierced their suicidal cognition just enough to allow them to breathe a little more easily through those suffocating negative emotions.

In fact, a scientific understanding of suicide is useful not only for vulnerable gay teens, but for anyone ever finding themselves in conditions favoring suicide. I say “favoring suicide” because there is convincing work—all tracing back to McMaster University’s Denys deCatanzaro’s largely forgotten ideas from the early 1980s—indicating that human suicide is an adaptive behavioral strategy that becomes increasingly likely to occur whenever there is a perfect storm of social, ecological, developmental and biological variables factoring into the evolutionary equation. In short, deCatanzaro has posited that human brains are designed by natural selection in such a way as to encourage us to end our own lives when facing certain conditions, because this was best for our suicidal ancestors’ overall genetic interests.

For good-hearted humanitarians, it may sound rather bizarre, perhaps even borderline insensitive, to hear that suicide is “adaptive.” But remember that this word means a very different thing in evolutionary terms than it does when used in clinical settings. Because natural selection operates only on phenotypes, not human values, even the darkest of human emotions may be adaptive if they motivated gene-enhancing behavioral decisions. It’s not that evolution is cruel, but as a mindless mechanism it can neither care nor not care about particular individuals; selection, after all, is not driven by an actual brain harboring any feelings about, well, anything at all. In no case does this sobering fact come into sharper focus than with the case of adaptive suicide. (I notice a similar reactionary confusion, incidentally, among “New Atheists” who bleat and huff in a Dawkinsian manner whenever they hear mention of the empirically demonstrable fact that religion is adaptive, something I’ll save for another day.)

Saying that suicide is adaptive may also sound odd to you from an evolutionary perspective, because on the surface it seems to fly in the face of evolution’s first rule of thumb, which is to survive and reproduce. However, as William Hamilton’s famous principle of inclusive fitness elucidated so clearly, it is the proportion of one’s genetic material surviving in subsequent generations that matters; and so if the self’s survival comes at the expense of one’s genetic kin being able to pass on their genes, then sacrificing one’s life for a net genetic gain may have been adaptive ancestrally.

Before we get ahead of ourselves, let’s first ease into the suicide-as-adaptation argument with a few nonhuman examples, which come mostly from the insect and arthropod worlds. Take male Australian redback spiders (Latrodectus hasselti), for instance, which seem content to be cannibalized by—to say the least—sexually aggressive female redback spiders during sex. Aside from putting a damper on an otherwise enjoyable act, being eaten alive while copulating would seem rather counterintuitive from an evolutionary perspective. But when biologists looked more closely at this spidery sex, they noticed that males that are cannibalized copulate longer and fertilize more eggs than males that are not cannibalized; and the more cannabilistic a female redback spider is, it turns out, the more desirable she is to males, even rejecting more male suitors. Another example is bumblebees (Bombus lucorum), a species that is often parasitized by invidious little conopid flies that insert their larva in the bee’s abdomen. Once infected, the bumblebee dies in about twelve days, and the parasitical flies pupate until their emergence the following summer. What’s interesting about this, however, is that parasitized bumblebees essentially go off to commit suicide by abandoning their colony and spending their remaining days alone in far-away flower meadows. In doing so, these infected bumblebees are leading the flies away from nonparasitized kin, increasing inclusive fitness by protecting the colony from infestation.

What is critical to take away from these examples is that the suicidal organism is not consciously weighing the costs of its own survival against inclusive fitness gains. Redback spiders and bumblebees aren’t mindfully crunching the numbers, engaging in self-sacrificial acts of heroic altruism, or waxing philosophically on their own mortality. Instead, they are just puppets on the invisible string of evolved behavioral algorithms, with neural systems responding to specific triggers. And, says evolutionary neurobiologist Denys deCatanzaro, so are suicidal human beings whose emotions sometimes get the better of them.

So let’s turn our attention now to human suicide. To crystallize his position, I present deCatanzaro’s “mathematical model of self-preservation and self-destruction” (circa 1986):

Ψi = ρi + Σbkρkrk

Where Ψi = the optimal degree of self-preservation expressed by individual i (the residual capacity to promote inclusive fitness);
ρi = the remaining reproductive potential of i;
ρk = the remaining reproductive potential of each kinship member k;
bk = a coefficient of benefit (positive values of b k ) or cost (negative values of b k ) to the reproduction of each k provided by the continued existence of i (-1 ≤ b ≤ 1);
rk = the coefficient of genetic relatedness of each k to i (sibling, parent, child = .5; grandparent, grandchild, nephew or niece, aunt or uncle = .25; first cousin = .125; etc.).

For the mathematically disinclined, this can all be translated rather straightforwardly as follows: People are most likely to commit suicide when their direct reproductive prospects are discouraging and, simultaneously, their continued existence is perceived, whether correctly or incorrectly, as reducing inclusive fitness by interfering with their genetic kin’s reproduction. Importantly, deCatanzaro, as well as other independent researchers, have presented data that support this adaptive model.

In a 1995 study in Ethology and Sociobiology, for example, deCatanzaro administered a 65-item survey including questions about demographics (such as age, sex and education), number and degree of dependency of children, grandchildren, siblings and siblings’ children, “perceived burdensomeness” to family, perceived significance of contributions to family and society, frequency of sexual activity, stability/intimacy/success of relations to the opposite sex, homosexuality, number of friends, loneliness, treatment by others, financial welfare and physical health, feelings of contentment, depression, and looking forward to the future. Respondents were also asked about their suicidal thoughts and behaviors—for example, whether they had ever considered suicide, whether they had ever attempted it in the past, or ever intended to do so in the future. The survey was administered to a random sample of the general Ontario public, but also to theoretically targeted groups, including elderly people from senior citizen housing centers, psychiatric inpatients from a mental hospital, male inmates incarcerated indefinitely for antisocial crimes and, finally, exclusively gay men and women.

Many fascinating—and rather sad—findings emerged from this study. For instance, the greatest levels of recent suicide ideation were in male homosexuals and the psychiatric patients, whereas the prison population showed the most previous suicide attempts. “It gets better,” sure, but we’re always at risk, and this evolutionarily informed model helps gay individuals to come to grips with that lamentable reality. But the important takeaway message is that the pattern of correlational data conformed to those predicted by deCatanzaro’s evolutionary model. Although the author offers the important disclaimer that “the observational nature of this study limits strong causative inferences,” nevertheless:

The profile of correlations agrees with the notion that suicidal ideation is related to conjunction of poor reproductive prospects and diminished sense of worth to family. Concordance of the data with the hypothesis is apparent in reliable relationships of reproductive and productive parameters to suicidal ideation.

One noteworthy thing to point out in such data is the meaningful developmental shift that occurs in the motivational algorithm. Whereas heterosexual activity is the best inverse predictor of suicidal thoughts among younger samples, this is largely replaced among the elderly by concerns about finances, health and especially the sense of “perceived burdensomeness” to family. A few years after this Ethology and Sociobiology report, a follow-up study in Suicide and Life-Threatening Behavior, conducted by an independent group of investigators seeking to further test deCatanzaro’s model, replicated the same predicted trends.

As persuasive as I find this model, I still had a question left unanswered by deCatanzaro’s basic argument, so last week I dropped him an email seeking clarification. Basically, I wanted to know how the suicidal patterns of contemporary human beings relates to those of our ancestral relatives, who presumably faced the conditions in which the adaptation originally evolved, but who in many ways lived in a very different world than our own. After all, even with guns, knives and drugs at our disposal, committing suicide is not always an easy thing to do, logistically speaking. In an article published earlier this year in Psychological Review, for instance, University of Rochester psychiatrist Kimberly Van Orden and her colleagues cite the case of a particularly tenacious suicidal woman:

Case #7 was described as being socially isolated when she attempted suicide with an unknown quantity and type of pain medication and also opened her wrist arteries. This action led to some degree of unconsciousness, from which she awoke … She then threw herself in front of a train, which was the ultimate cause of her death.

Now consider the suicide methods that would have been available to our ancient relatives in a technologically sparse environment—perhaps a leap from a great height where, if one weren’t successful, might have at least led to wounds sufficient enough for the person to eventually die from infection. Starvation. Exposure. Drowning. Hanging. Offering oneself to a hungry predator. Okay, so maybe there were more methods available to our ancient forebears than I realized. You see what I mean, though. Today, moving your fingertip but by a hairsbreadth is a surer route to oblivion than anything our species has ever known before; gun-owners might as well have an “off” button, it’s so simple now. (This is one of the many reasons that I don’t own a gun—deCatanzaro’s suicide algorithm is stochastic, which means that the figure it generates for a given individual is in a constant state of flux.) But deCatanzaro doesn’t see technological advances as particularly problematic for his adaptationist model. Fossils of suicidal australopithecines or early Homo sapiens aren’t easy to come by, of course. But, as he told me in his email response to my questions:

Evidence indicates appreciable rates of suicide throughout recorded history and in almost every culture that has been carefully studied. Suicide was apparently quite common in Greek and Roman civilizations. Anthropological studies indicate many cases in technologically primitive cultures as diverse as Amerindians, Inuit, Africans, Polynesians, Indonesians, and less developed tribes of India. One interesting old review was written by [S. R.] Steinmetz in 1894 (American Anthropologist 7:53-60). Self-hanging was one of the most prevalent methods of suicide in such cultures. There are also data from developed countries comparing suicide rates from the late 19th century through the 20th century. These data show remarkable consistency in national suicide rates over time, despite many technological changes. So, the data actually do not show a major increase in suicide in modern times, although this inference must be qualified in that there may have been shifts in biases in recording of cases.

Interestingly, the methods of suicide have changed much more than the rates. For example in Japan, hanging prevailed until 1950, after which pills and poisons became the primary method. In England and Wales, hanging and drowning were common in the late 19th century, but were progressively replaced by drugs and gassing. Motives may have been more constant than means (italics added).

I find deCatanzaro’s argument that suicide is adaptive both convincing and intriguing. But I do think it begs for more follow-up research. For example, his inclusive fitness logic should apply to every single social species on earth, so why is there such an obvious gap between frequency of suicide in human beings and other animals? Each year, up to 20 million people worldwide attempt to commit suicide, with about a million of these completing the act. That’s a significant minority of deaths—and near deaths—in our species. And there is reason to be suspicious that nonhuman animal models (such as parasitized bumblebees, beached whales, leaping lemmings and grieving chimpanzees) are good analogues to human suicide. In our own species, suicide usually means deliberately trying to end our psychological existence—or at least this particular psychological existence. And whereas most other accounts of “self-destruction” in the natural world seem to involve some type of interspecies predation or parasitical manipulation, human suicides are more often driven by negative interpersonal appraisals made by other members of our own species. In fact, Robert Poulin, the University of Otago zoologist who first reported on the altered behavior of those parasitized bumblebees, even urges researchers to use caution in referring to such examples as “suicide”:

The adoption of a more dangerous lifestyle by an insect that is bound to die shortly may be adaptive in terms of inclusive fitness, but no more suicidal than, for instance, an ageing animal taking risks to reproduce in the presence of a predator as its inevitable death approaches.

I’ve got a hunch that suicide, like fantasy-enabled masturbation, may require recently evolved social cognitive processes that are relatively unique—in this case, painfully so—to our species. There are anecdotes aplenty, of course, but there are no confirmed cases of suicide in any nonhuman primate species. Although there are certainly instances of self-injurious behaviors, such as excessive self-grooming, these are almost always limited to sad or abnormal social environments such as biomedical laboratories and zoos. Yes, grieving young chimps have been known to starve to death from depression in the wake of their mothers’ death, but there is no evidence of direct self-inflicted lethal displays in monkeys and apes. Perhaps Jane Goodall can correct me if I’m wrong about this, but as far as I’m aware, there are no cases in which a chimpanzee has been observed to climb the highest branch it could find—and jump.

I think part of the answer to this cross-species mystery can be found in another theoretical model of suicide, this one by Florida State University psychologist Roy Baumeister, which I’ve always viewed as the “proximate” level to deCatanzaro’s “ultimate” level of explanation for suicide. These are not alternative accounts of human suicide, but deeply complementary ones. While deCatanzaro explains suicide in terms of evolutionary dynamics, Baumeister zeros in on the specific psychological processes, the subjective lens by which a suicidal person sees the world. His model describes the engine that actively promotes the adaptive response of suicide. I should hasten to add that I don’t think either of them— deCatanzaro or Baumeister—necessarily see their models as being complementary in this way. I don’t even know if either is aware of the other. But this is how the two approaches have always struck me. Baumeister’s 1990 Psychological Review article on the subject, titled “Suicide as Escape From Self,” is, quite honestly, one of the most shockingly insightful manuscripts I have ever read, in any research literature.

And it’s that piece that I’ll kick off with later this week in “Part II” on the science of suicide along with other evolutionary tidbits. I’ll also discuss more current work, including some thoughts about why I believe modern schools place vulnerable adolescents, such as gay teens, at heightened risk of suicide simply by creating an artificial social environment of exclusively same-age peers, one in which specific pressure-points of ancestral conflict are bizarrely exacerbated. “It gets better” for gay teens only because we eventually get out of that unnatural zoo that is high school.


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  1. 1. michael T 3:38 pm 10/11/2010

    great article
    looking forward to part two

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  2. 2. sdphelan 7:10 pm 10/11/2010

    Wow! Sometimes Bering’s stuff is just too cute for me, and sometimes so outside my experience that it doesn’t resonate. This article is excellent — clear, relevant, concise. While satisfying my "just the facts, ma’am" bias, it still has deep emotional overtones. A great piece of writing. Thanks, and I can’t wait for part 2.

    And despite the Dawkins crack, I also look forward to the adaptive value of religion article. As a confirmed atheist myself, I have always been baffled about the widespread belief in the supernatural. Clearly, there must be some good reason for so many people to believe what to me in demonstrably wrong. So why do they? Perhaps because religion, like other social networks, helps us survive. But what is there specifically about religion that makes it so successful?

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  3. 3. Marc Lévesque 7:20 pm 10/11/2010

    I don’t think suicide is adaptive per say, one reason being it produces negative effects on the larger group and this prompts testing of alternative cultural assumptions (including social protocols and structures) in an effort to reduce the occurence of suicide, and because things that help will be selected for and things that don’t will be selected against, then evolutionarily speaking what is adaptive is to have increasingly worse organization lead to increasingly worse outcomes because this lowers status quo barriers and prompts testing of different organizational changes.

    Marc Barre Lévesque

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  4. 4. evolutionjunkie 12:11 am 10/12/2010

    Excellent, inclusive fitness probably explain some of it but sometimes many a time suicide is also a way to advertise "I need help," which really uses more resources from the community than saving the resources. I work in mental health crisis, suicide attempts aren’t always clear cut, sometimes people attempt chronically, and in an ultimate way of explaining this phenomanon, how about other self harming behaviours? Related but not exactly the same, and has different outcomes (costing more resources than saving it). Should we look at it as completely seperate?

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  5. 5. K.H. 12:20 am 10/12/2010

    Ah, that seems worth mentioning; a propensity for attempted (but not ‘successful’) suicide could well be adaptive as a way of securing help perhaps?

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  6. 6. Ang 8:01 am 10/12/2010

    Regarding the "artificial social environment of exclusively same-age peers" I would be interested in the effects of that throughout the lives of dominant groups like the boomers. It seems to me most departments of the large companies we work for are staffed (or stuffed) with same age peers as well. Is there any research on that?

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  7. 7. JamesDavis 8:34 am 10/12/2010

    It looks like there is not going to be a clear cut answer for such a high rate of suicide in humans, but one did kinda clog up my mind…’feeling of worth and care’. ‘Worth’ could be the "god" we are all looking for. …If you feel worthy or is convinced by people that you are worthy, you force yourself to live – if you feel unworthy or people convince you that you are unworthy, you force yourself to die. And it seems that the person who is committing the act of suicide has quit ‘caring’.

    Great article, Jesse.

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  8. 8. andrewtokyojapan 12:30 pm 10/12/2010

    Thank you for a thoroughly interesting and very thought provoking article. Just one correction with regards to the quote:

    "Interestingly, the methods of suicide have changed much more than the rates. For example in Japan, hanging prevailed until 1950, after which pills and poisons became the primary method." This is not at all true. Hanging has prevailed and still remains the most common method of suicide in Japan (over 70%) quite often within the home with many choosing the kitchen.

    Mental health professionals in Japan have long known that the reason for the unnecessarily high suicide rate in Japan is due to unemployment, bankruptcies, and the increasing levels of stress on businessmen and other salaried workers who have suffered enormous hardship in Japan since the bursting of the stock market bubble here that peaked around 1997. Until that year Japan had annual suicide of rate figures between 22,000 and 24,000 each year. Following the bursting of the stock market and the long term economic downturn that has followed here since the suicide rate in 1998 increased by around 35% and since 1998 the number of people killing themselves each year in Japan has consistently remained well over 30,000 each and every year to the present day.

    I would also like to suggest that as many Japanese people have very high reading skills in English that any articles dealing with suicide in Japan could usefully provide contact details for hotlines and support services for people who are depressed and feeling suicidal. Useful telephone numbers and links for Japanese residents of Japan who speak Japanese and are feeling depressed or suicidal:

    Inochi no Denwa (Lifeline Telephone Service):
    Japan: 0120-738-556
    Tokyo: 3264 4343

    Tokyo Counseling Services:

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  9. 9. oorca 5:43 pm 10/12/2010

    In my experience with First nations peoples in Canada,
    I can agree with James Davis that ‘worth and care" are definitely major aspects to the sad experiences that many First Nations communities encounter. I am struggling to fit this into Bering’s evolutionary adaptive paradigm, thanks for a well written article.

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  10. 10. Marc Lévesque 6:41 pm 10/12/2010

    Aboriginal language knowledge and youth suicide



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  11. 11. a31pthink 11:29 pm 10/12/2010

    "beached whales, leaping lemmings…"

    "The myth of lemming "mass suicide" is long-standing and has been popularized by a number of factors. In 1955, Disney Studio illustrator Carl Barks drew an Uncle Scrooge adventure comic with the title "The Lemming with the Locket". This comic, which was inspired by a 1954 American Mercury article, showed massive numbers of lemmings jumping over Norwegian cliffs. Even more influential was the 1958 Disney film White Wilderness, which won an Academy Award for Documentary Feature, in which staged footage was shown with lemmings jumping into sure death after faked scenes of mass migration. A Canadian Broadcasting Corporation documentary, Cruel Camera, found that the lemmings used for White Wilderness were flown from Hudson Bay to Calgary, Alberta, Canada, where they did not jump off the cliff, but in fact were launched off the cliff using a turntable."

    (a minor quibble, a pet peeve)
    thumbs up on the new ‘stache

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  12. 12. Fabrice LOTY 12:39 pm 10/13/2010

    The author of this article is really talented if only from an artistic viewpoint.
    As far as core issues are discussed, however, I found his line of reasoning fundamentally flawed.
    “However, as William Hamilton’s famous principle of inclusive fitness elucidated so clearly, it is the proportion of one’s genetic material surviving in subsequent generations that matters; and so if the self’s survival comes at the expense of one’s genetic kin being able to pass on their genes, then sacrificing one’s life for a net genetic gain may have been adaptive ancestrally.”
    Conferring the role of fixing genetic degradation to random, impersonal principles is far less tasteful than the artistic flavor exemplified in the author writing style.
    If the genetic material passed on from the ancestors is threatened by the continued existence of a particular individual, then it is reasonable to wonder why that individual appeared in the first place. The ancestors who produced such an individual are necessarily flawed, for nothing unclean can produce something clean. The problem is then to be traced back from the individuals who founded a human race prone to degeneration.
    In this regard, the historical answer provided in the Bible book of Genesis is more credible than any speculative, tentative explanation. The record documents the perfect creation of the human race, then candidly relates the fall of mankind’s ancestors (they thus forfeited their genetic assets). Sacrificing any innocent, flawed human being would be pointless, completely useless. God in his perfect balance and mercy saw it good to pay the high price by offering his own flawless Son as a ransom sacrifice to correct the flawed path imposed upon the offspring of Adam and Eve.

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  13. 13. Pececillo 3:29 pm 10/13/2010

    There are other interesting examples of suicide in nature. There are some rats that massively drown themselves in rivers when their population is too big.

    It is intrsting to propose suicide in a evolutive and mathematical perspective.

    Whe one thinks about suicide there is a particularly intresting point in Japaneese culture, where it was considered as a socialy accepted conduct under particular circumstances.

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  14. 14. bucketofsquid 4:24 pm 10/13/2010

    Fabrice, your theory that the story of genesis in the Bible is literally true would require a sadistic rat bastard as God because he deliberately created a defective species. Spare me the lame "they started perfect but were tricked by a snake" argument. If they were perfect they would not fall for a silly talking snake. Genesis is a work of gender bigoted fiction at its worst. The fact that there are several different versions to choose from doesn’t lend it any credence either.

    Recent research has shown that physical pain and social rejection trigger the same part of the brain. There is a point where the pain threshold has been exceeded sufficiently that anything, including death, that stops the pain becomes desirable.

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  15. 15. royniles 6:15 pm 10/13/2010

    It needs to be pointed out that "suicide" (if not self-sacrifice as well) requires the knowledge on some level that your individual being will ease to exist. The more those of your species have invested in their futures, the more the value of that existence, the more the cost to you of ending it by choice.
    Excellent article so far, however.

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  16. 16. Wayne Williamson 7:01 pm 10/13/2010

    nice(doesn’t sound right) article…like others i look forward to the next installment…

    nfscd(now for something completely different)…in my local(central florida) there has been a significant number of murder suicides…usually young men killing their family(or relatives) and then killing themselves…i wonder why all the time…any thoughts…

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  17. 17. lonkimay10 7:08 pm 10/13/2010

    answer to sdphelan: if you are trapped deep down a mine in Chile and you do not know what will become of you,try praying and asking God for mercy.This is reason
    why these men survived.Do you have a better choice?

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  18. 18. Squish 2:26 am 10/14/2010

    Fabrice: Thank you for my laugh of the day! I like the Bible myself, but I never confuse religion and science. Let’s leave this forum for science and reason, shall we? Your argument is weak by relying on such assumptions as "nothing clean comes from something unclean".

    People have myriad genes; some are adaptive in the circumstances they find themselves in, some are not. Adaptive or not, sometimes luck and consequences stalk the most adaptive specimens. Someone who is about to commit suicide may, in other circumstances (say, all the real men have suddenly died in a fight) be stud required to impregnate the whole harem, and quite willing to go on living life to the full. I bet you a nickel that if this option, though a fantasy, were somehow realistically presented to lots of teenagers with suicidal ideation, it would pick more than a few of them up.

    Nothing is inherently "flawed". Things are constantly reshuffled. Things are constantly judged by changing criteria. Some combinations emerge successful in the ever-changing environment, and others do not. If you don’t like science, read some Spinoza and get over your Angry God and Original Sin beliefs, they too may not be adaptive for our civilization. But that reshuffle and combination of ideas, like the genes of those who self-terminate, was still worth a shot. Sacrifice is not found solely on the cross, it is the fire that tempers a species fit by natural selection.

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  19. 19. sherylchilders 5:20 pm 03/17/2011

    I read this article a couple weeks ago, and I have been reflecting on it for some time. I even broke out my evolutionary biology text from college and buffed up on my knowledge on inclusive fitness, and I’ll tell you why this is wrong:

    First of all, what is not mentioned is that most, if not all examples of suicide in nature are in eusocial organisms – they are more than a 0.5 genetic relationship to their family, so have more significant evolutionary gain by protecting them. Not to mention that they may also reproduce asexually, so may have already left their genes behind in full. But humans are exclusively sexual organisms, with random sorting of genes occuring for each individual, so their evolutionary "desire" to maintain their own genes is so great, that the tendency to preserve siblings or parents is insignificant (they are more apt to preserve their own children).

    But, logically speaking, people don’t kill themselves non-selectively. That is, if this hypothesis were true, then people would kill themselves in ANY situation in which their kin’s survival were at risk, and their own death was less detrimental to the family’s genes. For example, people don’t kill themselves in situations like starvation or natural disaster. In fact, the survival instinct is stronger in these circumstances. One would risk their life to obtain food or shelter for themselves or family, but never kill themselves. And any life risking or self sacrifice would be in a direct relationship to others’ survival (they die to physically save others).

    People kill themselves for social, personal, and political reasons. Most common reasons for suicide are shame, humiliation, anger, loss, despair, and to protest. It’s genetic and evolutionary consequences are insignificant – that is, it is secondary to traits that increase survival, and not 100% heritable. If all traits were due to evolution, then fatal genetic diseases or diseases that cause sterility wouldn’t persist. But they do, because carriers still produce some sexually successful offspring, and the disease has nothing to do with increasing the healthy individuals’ survivals.

    In my opinion, evolutionary theories such as this are pretentious and offensive. It is reminiscent of so-called "ethnic biologists" of the mid to late 20th century. I would like to know how science puts a numerical value on the judgments of people who are dead – how they evaluated the the value of their life. In other words, this theory is pseudoscience that blatantly disregards its social impact.

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  20. 20. sherylchilders 6:40 pm 03/17/2011

    I really like this parallel you have drawn to religion. Anytime people try to explain human behavior in terms of pure, absolute science, there is usually a personal human intention behind it. This makes studying behavior especially prone to over speculation and false reasoning. These types of people believe that science can solve all problems, and so attribute it to some kind of supernatural form, which it is not.

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  21. 21. sherylchilders 6:48 pm 03/17/2011

    I don’t like your language and disrespect. Your arrogance and vulgarity discredit your point. Fabrice’s logical reasoning is sound, and his point well thought out. This is a subjective topic (as most of all social science is), and the fact that you believe in it so adamantly just shows that you use science as a form of religion, and that you are the intolerant one here.

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  22. 22. Beezy 8:16 am 01/19/2013

    Sherylchilders hit the nail on the head. This theory is completely bogus.

    For the overwhelming majority of our evolution, surviving was the primary concern. Look at history and your theory will all of a sudden make no sense. Our ancestors didn’t kill themselves because they were too busy trying to stay alive! For most of our evolution, we haven’t even lived that long. Our lifespan has just recently risen. Before civilization, humans had no time to play, they had no time to create art, they had no leisure time, they didn’t go swimming for fun, they didn’t think about life…because they didn’t have time to!

    Suicide is entirely unnatural. It goes against the core purpose of man! The reason why suicide has increased so much (and will continue to increase) is because it no longer takes any effort to live. Most people, especially those in the US, can do nothing their entire lives and still make it to age 80. Government assistance means that we can’t even die if we want to! The government won’t let us! How crazy is it that we even need a law that makes assisted suicides illegal!

    Unlike our ancestors who woke up every day with the intention of making it to the next one, we wake up and use our minds to do all sorts of things, especially to think about our lives and how we feel. Our ancestors didn’t have time to think about their feelings. They were busy fighting bears and warring tribes.

    Our ancestors were never unhappy because they didn’t have the time to get unhappy. We couldn’t imagine what that would be like even if we spent a lifetime trying to…and we definitely have the time to try.

    The fact you cite the high rate of suicide among the Greeks or Romans or whatever only shows the flaw in your theory. When looked at in the context of our evolution, the Greek civilization was very recent. The modern human came into being 50,000 years ago. But our evolutionary adaptations go back much much farther. Not counting the subtle differences between humans like skin color, nose size, or some other trivial trait, every single characteristic we have comes from the same evolutionary process that kept us alive. But they all helped us stay alive.

    We developed fears because the man who wasn’t afraid of the dark was less cautious in the dark and thus was less likely to survive and reproduce if he got eaten by a bear or pack of wolves. Same goes with any other feeling we experience…feelings of embarrassment, shame, and guilt all benefited us because if we alienated our tribe or didn’t conform to the norms, then we would be cast out or killed. It’s only recent that these evolutionary benefits have started hurting us. The same would apply to any other trait. Our ability to get fat so easily isn’t bad…it helped us survive when that was our ONLY concern in life. Why do you think the foods that taste the best have the most calories? Because the humans who liked eating high calorie foods would be more inclined to eat them and wouldn’t starve as easily. The mouth watering desire may now hurt us, but it helped us for millions of years when our desire to eat a big fat juicy steak outweighed the fear we had of getting hurt in the process of trying to kill whatever animal we had to catch.

    Look at history a little more and it becomes clear that suicide is present and prevalent because humans no longer have the purpose that they once did. Some do, some still fight every day to survive. But many people have no purpose. And having a job or a family doesn’t mean you have a purpose like it once did because we are not needed for their survival.

    To reduce suicide, we as a society need to address the issue of purpose. As the rest of the world develops, our entire planet will become a place where survival no longer becomes a concern because it’s so easy to live!

    The fears and worries and we have today are ridiculous because we have nothing else to worry about! When compared to the things our ancestors did on a daily basis, our lives are worthless. The ones who commit suicide have felt this the most.

    Now I’m not saying life is worthless, because it isn’t. But from an evolutionary standpoint it is.

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  23. 23. jbrack 1:42 pm 03/30/2015

    citing survival instincts where people do anything to stay alive as evidence to the contrary forgets the “do anything” part, which includes “suicide missions.” that is, “self interested” (whether self is oneself of their species) tasks where one is willing to risk death. another consideration is the possibility that suicidal persons place less value on life, and are at higher risk for committing mass murder. a person with nothing to lose can be very dangerous.

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