As the stag calms down


Aug. 1, 2014 – A study of 1,400 ancient and modern human skulls suggests that a reduction in testosterone hormone levels accompanied the development of cooperation, complex communication and modern culture some 50,000 years ago.

The research, published in today’s issue of the journal Current Anthropology, “uses craniofacial evidence to propose that lowered testosterone levels could explain the relatively sudden origin of modern behavior about 50,000 years ago,” says University of Utah biology graduate student Robert Cieri.

The idea being – to put it as crudely as possible – that lower testosterone would lead to less bashing over the head and more dialogue.

“Humans are uniquely able to communicate complex thoughts and cooperate even with strangers,” Cieri says. “New research on fossilized Stone Age humans from Europe, Africa and the Near East suggests these traits are linked, developed around 50,000 years ago, and were a driving force behind the development of complex culture.”

Homo sapiens, or modern humans, first appeared in the fossil record about 200,000 years ago, but evidence of modern behavior, such as symbolic artifacts and advanced tools are only about 50,000 years old, he adds.

So if that hypothesis is right, lower testosterone made all the good stuff possible – language, chat, jokes; social interaction and co-operation, art, pecan brownies. (Also nuclear weapons, global warming, genocide.)

I’m wondering if they mean lower testosterone in females as well as males or just males.

Patricia Churchland puts hormones at the center of human morality. Lena Groeger wrote up a talk of hers at Massimo Pigliucci’s blog in 2011.

It all begins with me. Ok, not me, but the self. Each one of us is equipped with a neural circuitry that ensures our own self-caring and well-being — values in the most fundamental sense. As Churchland likes to say “we’re all born with systems that are very deep in the values business.” Neurons in the brainstem and hypothalamus monitor the inner state of our bodies to keep us alive; they also cause us to run from predators or eat when we’re hungry. Without these life-relevant feelings we wouldn’t survive very long, let alone reproduce.

The next step is to move from self-caring to other-caring. In mammals, this shift occurs not by some radical new engineering plan, but by slight adjustments to the neural mechanisms that are already in place. Modifications to the emotional, endocrine, stress and reward/punishment systems motivate new values, namely, the well-being of certain others. It’s as if the “golden circle of me” expands to include offspring, mates, friends and eventually even strangers.

At the heart of all these modifications and changes to the brain is a relatively simple hormone called oxytocin. Oxytocin is thought to play an important role in mammalian bonding, evoking feelings of contentment and trust, reducing defensive behaviors like fleeing or fighting, and increasing the sense of calmness and security. Churchland describes the importance of oxytocin by telling her favorite story of all time — it involves voles.

Actually, two types of voles: prairie voles and montane voles. Prairie voles bond for life; montane voles are promiscuous. Male prairie voles protect their pups from harm, provide them with food, and fight off other males. Male montane voles take no role in guarding the nest, the female, or the pups. Scatter them across a room, prairie voles will collect back together in a huddle. Montane voles are content to be left alone.
What makes these furry little rodents behave so differently? In the 1970’s neuroscientist Sue Carter decided to look for the answer in the brain. She found that in a very specific place, the density for oxytocin receptors was much higher in prairie voles than in montane voles. Subsequent studies have shown that blocking the receptors for oxytocin in prairie voles changes their social behavior dramatically, and they no longer bond with their mates. For Churchland, this story was the clue that oxytocin was the neural mechanism for attachment, or what “Hume might accept as the germ of the moral sentiment.”
Oxytocin. Attachment. Feeeelings. Warm fuzzies. Without that there is no morality, there’s only self. Without that the greatest happiness of the greatest number is of no interest; you might as well talk about the greatest happiness of the greatest number of rocks. Without that the well-being of conscious creatures is of no more interest than the well-being of rocks. You need to add reason, to avoid making a whole lot of mistakes along the way, but reason isn’t the engine.


  1. Shatterface says

    Do you really want to go down the ‘cultural difference is down to hormones’ route?

    Especially a hormone implicated in such wonderful, fuzzy feelgood emotions like ethnocentrism:

    Human ethnocentrism—the tendency to view one’s group as centrally important and superior to other groups—creates intergroup bias that fuels prejudice, xenophobia, and intergroup violence. Grounded in the idea that ethnocentrism also facilitates within-group trust, cooperation, and coordination, we conjecture that ethnocentrism may be modulated by brain oxytocin, a peptide shown to promote cooperation among in-group members. In double-blind, placebo-controlled designs, males self-administered oxytocin or placebo and privately performed computer-guided tasks to gauge different manifestations of ethnocentric in-group favoritism as well as out-group derogation.

    That’s the hormone they are expermenting with on autistic kids.

  2. says

    Well we already know that, don’t we? That it’s both? We’re social and groupish, and therefore there are outgroups and hatreds and ethnocentrism and war. It’s good and it’s bad.

  3. Shatterface says

    Also, I don’t remember the Eighties being particularly notable for altruism despite half the population being loved up on oxtytocin-releasing disco biscuits.

  4. Shatterface says

    Well we already know that, don’t we? That it’s both? We’re social and groupish, and therefore there are outgroups and hatreds and ethnocentrism and war. It’s good and it’s bad.

    The OP seems to be arguing that it’s some sort of panacea:

    Oxytocin. Attachment. Feeeelings. Warm fuzzies. Without that there is no morality, there’s only self. Without that the greatest happiness of the greatest number is of no interest; you might as well talk about the greatest happiness of the greatest number of rocks.

    The problem with appeals-to-hormone type arguments is that they are far more likely to bite women in the arse. Oxytocin is released during child birth, oxytocin is good, therefore women should make babies.

  5. says

    Panacea? Not at all. I’m arguing that emotion is inextricably part of morality. People who don’t grasp that make a dog’s breakfast of trying to talk about it and think about it.

  6. John Morales says

    Shatterface @4:

    The OP seems to be arguing that it’s some sort of panacea:
    Oxytocin. Attachment. Feeeelings. Warm fuzzies. Without that there is no morality, there’s only self. Without that the greatest happiness of the greatest number is of no interest; you might as well talk about the greatest happiness of the greatest number of rocks.


    To me, it seems to be noting that there is a plausible biological mechanism (a hormone) which is associated with lower aggression just like there is one which is associated with attachment and fuzzies, and further opines that empathy (the fuzzies) is necessary to morality.

    So, I think she’s noting the significance of such things to our morality.

  7. Scr... Archivist says

    Shatterface @3,

    …the Eighties … oxtytocin-releasing…

    … disco biscuits.

    Be careful. It looks like you almost combined your MDMA and your Methaqualone.

  8. says

    This is a fascinating area! They are finding that the so called “sex hormones” are associated with cognitive roles in both sexes. No matter the hormone and the stereotype it’s doing something in both sexes and often the same thing. A favorite recent paper of mine is this one, mostly because the model in which the hormone functions is much less burdened by cultural baggage.

    Testosterone most closely maps to a dominance or competition versus nurturance switch from what I read and that is in both sexes. My question is that if you could somehow reverse the social roles would women show testosterone levels approaching what you see in men now? The establishment of physical gender is based on only a brief puff of the stuff early in gestation and there are likely many separated functions of these hormones in time and location.

    @ Shatterface

    Grounded in the idea that ethnocentrism also facilitates within-group trust, cooperation, and coordination, we conjecture that ethnocentrism may be modulated by brain oxytocin, a peptide shown to promote cooperation among in-group members.

    You have me intrigued so I’m going to try to read this tomorrow. Keep in mind that this effect if established could be dependent on the messages that one chooses to accept in ones culture and might be a matter of the emotional messages one chooses to listen to getting written and recalled more effectively. Children don’t get as much choice in parents or social messages and are inherently more impressionable (inter-generational racism might be a good example here).

    Don’t think I’m dismissing your ethical concerns, they are good ones. But the desired unknown here is precisely what the context that the hormone is meant to write to memory looks like.

  9. Blanche Quizno says

    Brony, there’s a window after birth when the mother’s hormone levels that facilitate maternal bonding are such that even what should be killed will be adopted instead. A recent example: mama cat adopts newly hatched ducklings – that nurse!

    I remember reading years ago about a study of female rats. If an adult female rat is presented with a newborn rat pup, she will kill it, But if the introduction is preceded by the injection of a minute amount of estrogen into the adult rat’s brain, the rat will instead adopt and mother the strange pup. Imagine the possibilities – if hormone-deficient mothers could have supplementation therapy that might help them bond better with their own sprouts!

    Also, keep in mind that dopamine triggers oxytocin release in the brain, a complex dynamic that affects emotional balance…

    Another effect of early maternal deprivation appears to be a permanent decrease in the production of oxytocin, one of our emotional modulation chemicals.17,18 Oxytocin regulates social recognition and affliction and modulates mood, anxiety and aggression. Use of illicit substances can alter the oxytocin-dopamine interaction. The interaction between oxytocin and dopamine may also be involved in drug-seeking behaviour.

  10. brucegee1962 says

    I heard a fascinating account on NPR about baboons. A guy was studying a baboon troop where the aggressive males found a garbage dump from a hotel, but had to fight through other baboons to get there. But the hotel threw out some tainted meat, and all these aggressive baboons died.

    The researcher was very depressed about this loss, of course. Before he left, though, he noted that among the baboons left behind, there were marked changes in behavior. There was more support for one another, and more mutual grooming among males (something that never happened normally with baboons).

    Twenty years later, he was back in the area, and took another look at the group. And he found out that these less aggressive, more nurturing behaviors had survived, even though none of the original baboons were still there.

    Culture matters.

  11. says

    Wow; that is interesting.

    It’s a bit like Germany and Japan after 1945. The aggressive baboons were dead or subdued, so a more liberal culture had room to grow.

  12. says

    Yep, cultural transmission of behaviors in apes and monkeys is pretty well established at this point, which raises the question of why so-called “skeptics” consistently ignore the influence of culture in human behavior. Yes, we’re animals; and, like animals, especially the ones we’re most closely related to, we’re heavily influenced by cultural cues in how we relate to each other throughout our lives.

  13. outsider79 says

    Craniofacial evidence… high testosterone leads to squarer faces according to motherboard. It’s also tied to a desire to dominate others, to cheat, and exploit other people.

    It may be a coincidence, but the example head shown in the middle of the article I linked to looks an awful lot like Mark Driscoll.

  14. says

    @ Blanche
    I’m actually quite fascinated by the Vulcan analogy. It’s not all useless, one does have to practice control of emotions to use logic well. But since all the really good fictional characters are fragmented or black and white versions of common human problems it’s not quite as simple as avoiding emotion. That’s actually a really lazy approach that leaves you blind to all sorts of things that come along with emotion. There are patterns in there. They are hard to work with and one needs to be ready to drop a possible hypothesis about particular manifestations of emotion at a moments notice, but the difficulty and chaos does not make the patterns any less real.

    I’m loving these more specific studies of precisely what various chemicals do in a raw computational sense. The difficulty is in translating it into what is going on in human brains and the minds grown from them through experience. Many of these creatures are far more stimulus-response then we are and the simple rules will likely be present in more complex fashion. We have this layer autobiographical memory capable of abstracting to all sorts of symbology, and we have far more choice in potential responses to what we perceive than most creatures because we have access to more context.
    Drugs that alter compounds that we know affect computational processes in the brain often produce altered feeling states. You get this new “thing” that pops up in your mind in certain circumstances. A context suddenly includes a new sensation. That thing can be contextualized in lots of ways and if someone is explicitly told that it will make them more sensitive to social information and contexts for example, they can prepare for that. They can treat it seriously and soberly and like the “indicator for rumination” that it is and not as a mere stimulus response. This of course does not prevent there being some things that do have simple stimulus-response results in humans.

    RE: Culture matters.
    It can get a little easy to overstate the case, but I’m getting pretty excited about the explanatory power of epigenetic effects. While we are still trying to lock down good evidence that supports specific phenomena in the emotional and psychological realms there are smoking guns everywhere that imply that we are clearly transmitting emotional presets via the experiences of previous generations. That IQ difference among races that racists love to go on about? What if the explanation is the shitty treatment that minority groups have been getting for generations? ADHD and Tourettes? This stuff feels very morally black and white and militant, my family is nearly all military and intense religious types going back centuries.

    I’m not expecting simple solutions or explanations, but when you are seeing papers like this trying to form good ideas about the patterns we are seeing, who the hell needs religion outside of convenient social organization?
    “Epigenetic transmission of holocaust trauma: can nightmares be inherited?”

  15. Blanche Quizno says

    @ Brony
    I remain fascinated by your perspectives on “tagging” emotions and how they’re contextualized within a framework, adopting context from those around you – you really put it in novel terms. I wish my son didn’t hang around with Evangelical Christians so much 😛

    I come from a long line of Baptist missionaries on my father’s side – his parents felt obligated to have 4 children (two to replace themselves, one to replace the one that would die, one to increase the population), but they clearly preferred preachin’ to parentin’ – as soon as each child turned 6, s/he was shipped halfway across the world to a boarding school/home for missionary kids. My father, the youngest, remains scarred from this maltreatment and neglect. When his parents thought their eldest child was going to die, they shipped him halfway across the world to a grandmother he’d never met, so as to not bother them with his selfish illness and inconvenient dying. Because Jesus was all that mattered, you see. He unexpectedly recovered.

    My Tourrette’s son is inexplicably drawn to WWII, Naziism, the Soviets, and white supremacy, which is shocking – we his parents are very progressive politically and socially. For ages, the only songs he wanted to play on the piano were German and Soviet anthems (“Die Wacht Am Rhein” is the song the Nazi soldiers are singing in this clip: ) or old country/Confederate songs. Fascinated by warfare and historical conflict – this summer, he visited Normandy on a school trip to France and found it deeply moving. In a little antiques shop, he bought an old rusted bayonet for his dad – there was trouble at customs, because they won’t let Nazi artefacts cross the borders!

    So I can definitely relate to everything you’re saying! I’m very interested in that inherited memory idea – it has been demonstrated in mice, I think: Here we go

    I’ll sheck out your link and get back to you.

  16. Blanche Quizno says

    @ Brony – per your article, I wonder if this “inherited nightmare” idea helps explain people’s lingering deference to Christianity, which used the most horrible methods imaginable to terrorize people into conformity and obedience. Also the deep societal changes in the wake of the devastating plagues – Justinian, Black – which could not be explained and were thus terrors – what moved into all those openings created from all those deaths, given the disruption of society, and what were their motivations? The Black Death spawned a novel art genre, for example – the Totentanz, or “Dance of Death”. It influenced music and art, even church decor, for centuries! How much of that is due to the inherited trauma of those plague survivors?

  17. johnthedrunkard says

    But… the menz activists love to point out that contemporary men’s testosterone levels are officially plummeting.
    “Most of you probably know that your individual testosterone levels fall as you age. But studies have shown that men today, across the population, have about 20% less testosterone than men the same age did just two decades ago. That’s a huge dip.”
    With links to REAL scientifical looking references:

    So no wonder men are 20% more social and supportive than they were 20 years ago.

  18. says

    This is where I’m going to get more tentative because of what I said about being careful to not overstate the case. There are likely things in what I’m reading into the literature and my experiences that I want to be true and don’t realize it and I have to admit that for me at least (and some of the other with TS that I have met) black and white thinking is a natural tendency. So while I do come to strong conclusions about things that I infer and seem to be implicated by what I have read and correlated with my experience and the experiences of those I have talked to, I treat all of them as hypotheses that can be discarded just as soon as better data comes to light. The good news is that the same too-easily triggered habit system that can allow the bothersome tics, obsessions, and compulsions can be shaped to create strong and easily triggered rules of personal conduct. I try to have rules like this that let the data tell me what it is on its own terms and while I’m not assuming that you are being sloppy, I have to provide warnings like this when people ask me about the more hypothetical things that I have been obsessing over when it comes to brains and minds.

    The way that I describe these emotional processes are attempts at metaphors that try to convey how the reality seems to work based on the way that brains do what they do. It took me a while when I first started digging into this stuff because you have to rethink a lot of how it is that you are putting together reality from the anatomy and that sort of context shift is like replacing a lot of mental filing cabinets and reorganizing conceptual categories. The stream of consciousness literally gets patched with new frames for everything and I really could not look human behavior the same way after starting to tie anatomy (and changes to it unique to my type of human) to elements of mind. In some respects I let that inner demon choose my words for me, but only with my permission and with thought because that thing is really all about the simple emotionally satisfying words to be applied to complicated things. Such words are effective and useful, but far too unsubtle on their own for today’s problems. I’m not the same person that I was five years ago when I was forced to leave science behind to figure this stuff out (I’m currently in the process of trying to get back into research, applying anyway).

    In my experience a big chunk of what TS is all about in terms of conscious experience is that the intensity of a subset of sensed emotion is turned up. If that is affected by experiences of one’s ancestors in terms of alterations to gene transcription the most immediate concern of most people would be what actually looks like on a broad level. They will likely look like the sort of inner presence that I mentioned above, a felt state that occurs with a specific context. The sorts of contexts will be really general things like the intensity and duration of reaction to social embarrassment or offense, or how readily one will act on urges to react in anger. In other sorts of transgenerational effects you may see greater tendencies to form anxiety in response to various stresses, or even to be more sensitive to negative aspects of things over positive aspects. But whatever they are they will be computationally simple things that end up as context sensors that will be sensible responses to the natural world that participate in multiple parts of cognition. Things like metabolism settings for starvation conditions, or a more cautious and critical (and probably some pessimistic and paranoid) mindsets for environments with lots of predators. There will be attempts to tie culture to things inappropriately and I agree with the criticisms of evolutionary psychology that you hear around here and make no mistake, I’m giving you my version of it so don’t tune out any criticism you might hear. Evolutionary psychology is real, but we collectively have a really hard time describing it objectively.
    When we are children we are more stimulus-response and we have to learn recognize that inner sensation of emotion and act with deliberation, mostly though teaching, role-models, and interaction but I won’t say that there are not people who are born with more introspective capabilities (in fact introspection abilities could be a target of a transgenerational emotional control, do you think about what the authorities tell you or do you follow orders?). We can choose let our first response to an urge or impulse happen, or we can learn to sense the impulse, consider different responses and then act. The society we grow up in shapes this strongly and I often think of society as having momentum as current biases are reinforced by how the next generation is raised. I don’t believe that these transgenerational modifications have to be “life sentences” (they do fade with the generations). Rather they are probably loaded biases that can be written over to varying extents with life experience in a process that is probably easier when you are younger (many speak of “early interventions”). But some emotional settings may be permanent in an individual or extremely hard to write over.

    At the anatomy level in terms of what these changes are doing computationally I would say that TS makes you more “motor minded” analogously to how someone like Temple Grandin (a fantastic autism advocate) has described her autism as being “visually minded”, but it might be “habit minded” (or even “ritual minded”) instead because I’m not sure if it’s motor related specifically or if it has to do with patterned behavior that also affects the motor system. TS is full of observations on pattern phenomena in language and more.
    Motor programs are easy to trigger resulting in tics which look like very much like strong habits that can be shaped. The mental habits may be connected to explanations of the origins of our symbolic abilities which are thought by some to be extensions of our motor system into other parts of cognition. When you train a primate that does not use tools in the wild to use tools, you see parts of the brain associated with the limbs in question (and regions that store context information for when, where, why and how for the limbs) expand and change.
    These regions are very expanded relative to other primates in human evolution and there are likely similar effects for eye-tools (telescopes). Conceptual tools get more interesting still and there I’m convinced there is a good reason for society to be worried about how likely we are to use one another as tools with respect to things like the “ends versus means” issue and concerns for autonomy. Essentially there is a motor aspect to perhaps all of cognition that helps to produce more complex patterning of reality and it’s overactive in TS. The effects are not all negative though and there is some literature on enhancements at some levels of cognition that I have written about elsewhere.

    An aspect of this that I want to explore more is the fact that I think we also have more of a desire to lose ourselves in sensations like food, sex and other pleasure like we also overstimulate on the feeling of our emotions (problems with excess rumination in unhealthy ways). It’s sensitive but there is data showing complaints of inappropriate sexual expression as well as things like anger control problems in TS. I’m not sure if there is a bias towards base pleasures or not but I have been kind of manic about how I feel about brain science on occasion though I am kind of a simple brute at heart. It’s a matter of what systems seem to dominate in terms of global effects. If I had to say what my primary motivating mental state is like it would be “DO”. I always have the urge to be doing, to be and feel busy, to act, to react. I almost literally can’t ever relax. I think it’s exactly like we are following signals sensed more intensely and I almost think in routines and analogous connections instead of things like pictures or words or voices.

    Getting to your son, I have some ideas but these are my thoughts on possibilities that someone might consider as a testable question but not one with collected data (at least directly). Definitely keep this a discardable hypothesis in your head. Precisely which of these are TS, ADHD, or OCD and which are the results of society are not all determined.
    First a more general frame. Think about the high intensity emotion as the signal relayed by the stimulus being “louder”, and the simple “stimulus-response” being somewhat analogous what are being called system-one responses. System-two matures as we age. I think that a problem related to increased intensity is a decrease in analogs to resolution and contrast that can cause hierarchical processing effects. In my mind often multiple responses compete for attention and I have some odd common logical errors as a result such as a tendency to say or type the opposite of a thing with a polar opposite like Right/Left, or East/West. It becomes harder to make sense of things so routines and rituals increase accuracy and structure in our world. Some social categories just don’t make as much sense to us because of these resolution/contrast issues and that shows up in data as problems with non-literal language, expression interpretation, sarcasm detection, and accuracy with social rules. I hesitate to generalize farthur but for me I have always been very anti-fad (until this Brony thing), get no joy from following sports (group oriented social competition and surrounding fanfare), automatically distrust larger social structures and expect them and authorities to be held to higher standards, am more “asocial” in general and prefer fewer but closer friends. And obviously I obsess over the forms that social interaction and its associated rules take and how we unconsciously regulate social interaction. I live my life in a way where I essentially try to turn down and control these things rationally and in ways that emphasize things like reducing suffering and evening out relative levels of power in society so we are all about as powerful as the next person. Everyone can feel free to speculate about how this might relate to things like conservative politics without worrying about me feeling insulted. I essentially try to share the cheat codes for what I discover about how these things in my head may relate to society at large around here anyway.
    In that frame what you describe in your son shows a interest in similar social categories, but that interest was shaped by things would be more familiar with. War and authoritarian governments are probably fascinating to people with more rule-based, ritualistic mindsets. Our increased tendency for error and accident (in more peripheral attention areas when not focused, what we are focused on appears to have greater accuracy in some contexts) probably create a greater attraction for order in society that helps us with predictability and accuracy through comfortable routine. We may also focus more on the basic things in life that are critical and vital for society in the lower levels of Maslow’s hierarchy. Or it’s tendency to focus on the simpler aspects of things. I suspect we have an advantage in getting “the gist” of things and may be good generalists but can have a hard time expanding into the details. But what we do get into our heads manages to stay there quite firmly and can be manipulated pretty deeply so the effort is worth it, but makes us rather structure and rule obsessed.

  19. says

    Pattern minded may be more likely than motor minded. I found this.
    “Sexually dimorphic neurons in the ventromedial hypothalamus govern mating in both sexes and aggression in males.”
    The hypothalamus seems to me to be involved in lots of behavior patterning. Cells involved in both sex and aggression? If a TS link exists I sense effects on “approach” or “approach and interact” at a basic computational level. That would correlate with that “DO” I have in my head all of the time.

  20. Blanche Quizno says

    @ 19 johnthedrunkard: But the REASON is that, for the last 20 years, those horrid FEMINISTS have been emasculating all the menz!!!

  21. Blanche Quizno says

    @ Brony, I can’t thank you enough! I hope you don’t mind if I share your ruminations with my husband (he’s a PhD in microbiology). I am also going to share some with my son – the whole getting caught in anger loops, the urge to “do” – all this describes him to a T! Or a TS!! I know – lame…

  22. says

    No problem!

    I’m happy to help. Learning what you are as well as who you are can be so illuminating, and terrifying, and humbling, and honestly fun. I’m happy to be able to make it useful to someone else. I just wish everyone could get into this material at it’s own level like this.

  23. Hj Hornbeck says

    Aha, I found this thread at last! From the linked article:

    He notes that lower testosterone is associated with social tolerance and cooperation in bonobos and chimpanzees, and with less aggression in humans. Cieri speculates that higher population densities could have triggered the shift towards lower testosterone levels, as people increasingly had to work together to succeed, and being highly aggressive became less advantageous.

    That bolded bit? Not established by the research. I covered this way back in the day:

    Testosterone is another ball of wax. We have tonnes of studies of men, looking for a link between aggression and the so-called male hormone. There’s plenty for a meta-analysis, and so far four have been done. The latest is a rehash of an earlier analysis, done in 2001, which the authors claim was flawed. Redoing the numbers, they found… a trivially small association, only 54% predictive.

    Archer’s re-exam of Book’s meta-analysis doesn’t have a quote-friendly abstract, so I’ll stick with Book’s original research:

    In non-human animals, the relationship between testosterone and aggression is well established. In humans, the relationship is more controversial. To clarify the relationship, Archer conducted three meta-analyses and found a weak, positive relationship between testosterone and aggression. Unfortunately, each of the analyses included only five to six studies. The aim of the present study was to re-examine the relationship between testosterone and aggression with a larger sample of studies. The present analyses are based on 45 independent studies (N=9760) with 54 independent effect sizes. Only studies that reported a p-value or effect size were included in the analyses and the sample may underestimate the proportion of non-significant findings in the population. Correlations ranged from −0.28 to 0.71. The mean weighted correlation (r=0.14) corroborates Archer’s finding of a weak positive relationship.
    Book, Angela S., Katherine B. Starzyk, and Vernon L. Quinsey. “The relationship between testosterone and aggression: A meta-analysis.” Aggression and Violent Behavior 6.6 (2001): 579-599.

  24. says

    Yes, thank you Hj. The correlation maps to something like dominance instead. I actually meant to mention something similar but it slipped my mind. Dominance need not involve overt aggression. So many species do dominance without doing overt aggression and in our own societies dominance shifts can be aggression, but it’s also so many other things like social posturing as well. Good point.

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