We’ve discussed signaling and status endlessly on LW; I think this is right up our vein: a 2011 review of research on the connections between famous male hormone testosterone and various forms of social interaction and especially social status, Eisenegger et al’s “The role of testosterone in social interaction”. (I grabbed this PDF in the short time Elsevier left full-text available, but only now, with some modafinil-powered spare time, have gotten around to excerpting it for you guys.)

1 Abstract

Although animal researchers established the role of testosterone as a ‘social hormone’ decades ago, the investigation of its causal influence on human social behaviors has only recently begun. Here, we review and discuss recent studies showing the causal effects of testosterone on social interactions in animals and humans, and outline the basic neurobiological mechanisms that might underlie these effects. Based on these recent findings, we argue that the role of testosterone in human social behavior might be best understood in terms of the search for, and maintenance of, social status.

2 Excerpts

Is testosterone simply aggression promoting (a sort of ‘roid rage’)?

Early evidence for the role of testosterone in social behavior suggested that it facilitates overt physical aggression (see Glossary) in social contexts. For instance, castrated rodents, which have little, if any, testosterone circulating in their blood, show a near-complete absence of physical fights; however, fights can be fully restored by providing testosterone supplementation to these animals [03]…high testosterone levels in male prisoners have been linked to having a history of rape, murder and armed robbery, and relatively lower levels to a history of theft and drug abuse [08]. A similar pattern was observed in a study of female prison inmates [9]. However, the causality in these studies remains unclear

Probably not:

the existing evidence for a link between aggression and testosterone in humans is relatively weak, but positive [12]. Even if one accepts the fact that reactive aggression can be measured in a controlled laboratory environment, results are similarly inconclusive: recent studies found a positive relationship between baseline testosterone levels and laboratory measures of reactive aggression (reviewed in [11]), but others also reported null findings (in larger samples) [13]. Most importantly, however, a causal role for testosterone in forms of reactive aggression could not be confirmed, as neither long-term nor acute administration of testosterone had an effect [13,14].

This may come as a surprise:

Folk wisdom holds that testosterone causes antisocial, egoistic, or even aggressive behaviors in humans. However, the correlational studies discussed above already suggest that this simple folk view probably requires revision [34,56]. A recent placebo-controlled testosterone administration study found support for the idea that the testosterone-aggression link might be based upon ‘folk’ views: individuals given placebo who believed they had been given testosterone showed less fair bargaining offers compared with those who believed that they had received placebo, thus confirming people’s stereotypes about the behavioral effects of testosterone.

The null findings may be due to a possible confounding effect of homeostasis, but that wouldn’t cover the null on acute administration:

The first study to use a causal testosterone administration procedure in an experimental economic setting did not find any effects on several economic social interactions [14]. Because the study used long-term administration of testosterone, this null finding might be due to secondary feedback effects on the neuroendocrine axis (i.e. suppression of endogenous testosterone production owing to chronic administration). In general, acute administration shows greater reliability in the production of both behavioral and neurophysiological effects (reviewed in [55]).

‘Dominant’ looks like a better perspective than ‘aggressive’:

rhesus monkeys with high testosterone levels use stares, threats and displacements, rather than overtly aggressive interactions, to ascertain high social status [16]…[saliva] measurements of testosterone at a single time-point correlate positively with high dominance in both adolescents [19,20] and adults [21,22]. In addition, salivary testosterone levels correlate with implicit measures of power motivation [23] and increased vigilance for status threats [24,25]. As a result of these relationships, and the moderate stability of testosterone levels over time, some have suggested that baseline testosterone levels reflect a personality trait [26]

men show a larger increase in testosterone when exposed to the scent of an ovulating woman compared with that of a non-ovulating woman or a control [27]. Apart from sexual social stimuli, which are reliable inductors of a testosterone response [28,29], social interactions outside a direct reproductive context have also been shown to induce a testosterone response [01]. In particular, testosterone levels rise within minutes in anticipation of both physical and non-physical competitive situations; for example, dyadic food competition in chimpanzees [30], or tennis, chess or domino tournaments in humans (reviewed in [31]). Testosterone also reacts to contest outcomes [32], and not just to anticipation: for instance, stock traders show higher testosterone levels if their daily profits are above average, and winners of soccer matches show higher testosterone levels than do the losers [33]….causal manipulation of social context (e.g. rigged contests) confirms a causal effect of winning situations on testosterone levels (e.g. [34–38]). These effects can be large; for example, merely watching oneself win a competitive interaction on video produces a 40% testosterone surge from baseline [37].

This interest in dominance leads to mental changes (I am reminded of self-deception):

individuals who generally have higher scores on self-reported dominance and higher basal levels of testosterone show vigilant responses to angry facial expressions (reviewed in [42]). Furthermore, exogenous administration of testosterone increases the sympathetic heart-rate response to angry, but not to happy facial expressions [43] (Figure 2). Although this could theoretically also reflect autonomic arousal as part of a fear response, testosterone has been shown to reduce fear [44], suggesting that dominant people perceive an angry face as a challenge….a recent testosterone administration study has shown that facial mimicry [“a precursor of empathy-related processes occurring automatically”] in response to emotional facial expressions is relatively suppressed after a single dose of testosterone [48]…a single administration of testosterone to young females leads to a significant impairment in the ability to infer emotions, intentions and feelings from the eye region of the face [49]. In addition, the same study established that subjects’ second-to-fourth digit ratio, which is thought to be a marker of prenatal testosterone exposure, is largely able to predict this effect…In line with this are findings of decreased trustworthiness ratings of facial photographs in subjects who received a single dose of testosterone [51]. Crucially, this effect was driven most strongly by those who trusted easily, suggesting that testosterone adaptively increases social vigilance in these trusting individuals to better prepare them for competition over status and valued resources

(The jokes about women and men almost make themselves.)

Not all of these changes are what one would naively expect (see previously about the ‘folk theory’ of testosterone):

one acute dose of testosterone in women increased the fairness of proposers’ bargaining offers in an ultimatum game [13] (Figure 3). An important motive driving proposer behavior is to avoid the rejection of the offer. Thus, if testosterone increases the concern for status, subjects who received testosterone might have perceived a rejection as more aversive, inducing them to make fairer offers…Another study [57] found that testosterone administration prior to an ultimatum game resulted in decreased generosity in a sample of healthy males if repeated measures were not controlled for. The results are insignificant, however, if the fact that the same subject participated in the ultimatum game several time is correctly controlled for statistically. Moreover, a recent study suggests that a low second-to-fourth digit ratio (high prenatal testosterone exposure) is associated with unfair proposer offers if subjects had previously received an unfair offer when in the responder role [58]. Many possible spill-over effects can thus occur in a within-subject design such as that used in [57], where subjects repeatedly play as a proposer and a responder, rendering the interpretation of the results difficult.

I found interesting the material starting page 267, “Neurobiological mechanisms underlying the role of testosterone in social status hierarchies” (due to my own musings about the possible effects of masturbation went that it might be misinterpreted as reproductive ‘success’ which reduces risk-taking or activity in general):

Maintaining a high status position requires an increased sensitivity for aversive events and impending social threats, particularly those that challenge the high social status of an individual. As we show below, testosterone appears to be able to influence such processes; in particular, it appears to confer high motivational drive, low fearfulness and high stress-resilience, either directly or via interactions with other hormones and neurotransmitter systems.

Fear & stress:

Among healthy young men, the blood oxygen level-dependent (BOLD) response in the amygdala to fearful and angry faces co-varies positively with individual differences in serum testosterone concentrations ([63,64], but see [65]). Exogenous testosterone has been shown to activate the amygdala in young women viewing angry facial expressions [66] (Figure 4). A mechanism underlying these observations might be that testosterone induces a functional decoupling between OFC and amygdala activity [67,68]…In humans, single acute doses of testosterone have been shown to reduce subconscious fear (Figure 5) and fear-potentiated startle [44,89].

…In face-to-face interactions, individuals are assumed to compete for status in fairly well-defined contests, each trying to ‘outstress’ the other with verbal and facial cues, and the fact that low-ranked members show more stress symptoms than higher-ranked members during mutual interaction is a common feature of status hierarchies [40]. Stress probably also plays an important role in anonymous competition. Hence, stress resilience might enable an individual to cope with a challenge adaptively. Studies in animals have confirmed that testosterone downregulates the hypothalamic-pituitary-adrenal stress response [90]. It has also been shown to attenuate the sympathetically mediated stress response to aversive stimuli in humans [91].

Motivation & learning:

Reward-based reinforcement effects in animals have been observed within short time periods (30 min) after systemic administration of testosterone [79], suggesting that a testosterone surge following a status-relevant social stimulus might reinforces any behavior that led to that testosterone response in the first place. In humans, patients who are hypogonadal (testosterone levels too low) show apathy and lack of motivation [80], whereas testosterone administration in healthy subjects induces motivation to act [81] and upregulates activity in the ventral striatum [82]

Summary of foregoing:

Testosterone administration studies confirm that the hormone also has fear-reducing properties in humans. A further important function of testosterone is its role in motivation; animal models have shown a tight link with the dopaminergic system within striatal areas. Thus, together with the ability to reduce fear and buffer stress responses, testosterone might have a pivotal role in promoting upward movement in a status hierarchy by facilitating the engagement in a competition for status. By contrast, testosterone can promote threat vigilance, which enables an individual to not only detect potential status challenges, but also, as a consequence of, and facilitated through the mechanisms detailed above, act accordingly to defend its high status position. These effects might be mediated by the amygdala

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New Comment
39 comments, sorted by Click to highlight new comments since: Today at 9:41 AM

Let me tell you about my personal experience with testosterone, which may be of some interest. At the age of 21 I was a junior in college majoring in math and physics, a very thin, effeminate, extremely shy nerd who was sometimes mistaken for a 14 year old prodigy. When I finally saw a doctor and it was found that I produced no natural testosterone, I began giving myself injections of the hormone. Anxious to get results, I often gave myself more than the prescribed dose. The results were profound: Within 6 months I had undergone an accelerated puberty which resulted in a bad case of acne, a much better physique and nearly caused me to flunk out of college. I was often overwhelmed, walking around campus among my peers, by the apish nature of my species. Having lost interest in intellectual pursuits, all I really wanted to do was fight, fuck and pick bananas off of trees. I even began shoplifting for no apparent reason other than it seemed like something I could get away with.

I managed to barely graduate, but my life was thrown into disarray from which I have never fully recovered. It became frighteningly clear to me just how much human lives are controlled by chemicals rather than any moralistic narratives. While a high testosterone level certainly gives you energy, ambition and fearlessness, it probably isn’t very helpful in a technological civilization which requires people to sit at computers all day manipulating symbols. My guess is that women are going to rule in such a world, as high testosterone men become increasingly useless and tend to wind up in prison. It may get to the point where testosterone levels will need to be technologically lowered to reduce crime and make men more socially acceptable.

So understand this, all you LessWrong nerds: when you see someone who is like a thug to you, that he is in the grip of an incredibly powerful mind-altering chemical called testosterone which, more than any other, is responsible for the evil that men do.

You gave yourself a powerful mind altering chemical that most peoples bodies/minds have grown up with and have built up mental models, skill, techniques to handle it. Your mind however did not have a half a life time to learn how to handle it. That is why:

it probably isn’t very helpful in a technological civilization which requires people to sit at computers all day manipulating symbols. My guess is that women are going to rule in such a world, as high testosterone men become increasingly useless and tend to wind up in prison. It may get to the point where testosterone levels will need to be technologically lowered to reduce crime and make men more socially acceptable.

So understand this, all you LessWrong nerds: when you see someone who is like a thug to you, realize that he is in the grip of an incredibly powerful mind-altering chemical called testosterone which, more than any other, is responsible for the evil that men do.

seem to be based on thin evidence.

Upvoted for informative account of experience, but not for inferences drawn therefrom (I agree with Davorak on that).

This is way way old I know, but I thought I'd give a contrasting viewpoint. I too produce no natural testosterone. I noticed something was off around age 16 and started getting injections at age 17, I think. My pubertal development was more gradual, probably taking about a year and half or so. I noticed no significant personality changes during that time or since (other than being horny all the time, of course), and definitely no increase in aggression (I started as a very passive person if you want a baseline). I don't think my physique changed that much (I was very skinny before taking testosterone and I still am), but I had a significant growth spurt. I got the occasional pimple, but no acne. Honestly the whole transition was very smooth and didn't cause me any trouble whatsoever - leading me to theorize at the time that late teens might actually be a better time to go through puberty, because one is cognitively more able to handle the abrupt changes. The above seems to argue against that though.

Incidentally, my testosterone dose at the moment gives me a peak level that's on the high end of normal. So I don't think it's a case of me not getting "enough" testosterone to make me aggressive, unless the effect only shows up for extremely high levels.


Trans men tend not to do that.

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The most interesting info on this topic I have seen is a trans guy's biography:

Becoming a Visible Man.

They interviewed the author on NPR and it was compelling audio (could not find it with a basic search). The thing which stuck out was his report that after he started taking the testosterone his personality and behavior and world view all changed very radically. He would be walking down crowded city sidewalks and intentionally bump into guys and behave in other defiant and challenging manners which were unimaginable to him before he started the therapy when still a bio woman.

I heard that FtM transsexuals tend to be much more aggressive than ("normal") males, because unlike men they aren't used to living with those hormones since they were kids.

Part of the problem here is that even if testosterone had absolutely no effect on aggression at all, we would still see people taking testosterone injections acting more aggressive. Why? Because the common belief is that testosterone will make you more aggressive. Give them saline and tell them it's testosterone and they'll start bumping people in the street as well.

To test whether there is an actual effect going on here, they'd need to look at what how two different groups of FtM transsexuals respond when one is placed on a placebo, and one given testosterone. The article linked to by Gwern discusses this effect of perception on behavior:

Folk wisdom holds that testosterone causes antisocial, egoistic, or even aggressive behaviors in humans. However, the correlational studies discussed above already suggest that this simple folk view probably requires revision [34,56]. A recent placebo-controlled testosterone administration study found support for the idea that the testosterone–aggression link might be based upon ‘folk’ views: individuals given placebo who believed they had been given testosterone showed less fair bargaining offers compared with those who believed that they had received placebo, thus confirming people’s stereotypes about the behavioral effects of testosterone. More importantly, however, when statistically controlling for this belief of treatment assignment, one acute dose of testosterone in women increased the fairness of proposers’ bargaining offers in an ultimatum game [13] (Figure 3).

From the Reddit discussion:

It reminds me of that article written by a female-to-male transsexual about the effects of introducing testosterone to his body. He specifically mentioned that most activities (especially sex) had become obscenely more focused on the goal or end-result, and how the rest of the journey didn't matter so much. I can probably find it again if anyone's interested. http://www.reddit.com/r/cogsci/comments/lipbp/testosterone_and_social_functioning/c2t254p

linking to http://tranifesto.com/2010/06/30/testosterone-and-sex-drive-my-second-adolescence/ - interesting indeed.

So, would it be advisable to use testosterone as an anti-akrasia aid or social phobia suppressor?

Advisable? I certainly wouldn't advise it - modafinil or melatonin, yeah, I've read a fair bit of material and think I know the minimal risks, but not testosterone. I'm a little concerned about the mixed bag I see in some of the case studies. For example, Andrew Sullivan has covered his experience with prescription testosterone:


If someone is going to try that, they should report back (considering there are so many fearless nootropic experimenters here already, it seems possible at least one or two people will try it).

I do not plan to supplement my natural levels but I do intend to use supllemental test to stay at my baseline as the level naturally drops off with aging.

Isn't testosterone also an immunosuppressant? It would need to be a pretty big effect to merit the tradeoff.

Anecdotally, I've always had social anxiety despite being, I'm fairly certain, on the high end of the natural testosterone distribution (very strong libido, very easy to build muscle mass, my chin has actual corners that make shaving a pain, etc.).

Isn't testosterone also an immunosuppressant? It would need to be a pretty big effect to merit the tradeoff.

Maybe. From Sullivan:

For reasons no one seems to understand, testosterone may also be an immune suppressant. High levels of it can correspond, as recent studies have shown, not only with baldness but also with heart disease and a greater susceptibility to infectious diseases. Higher levels of prostate cancer among blacks, some researchers believe, may well be related to blacks' higher testosterone levels. The aggression it can foster and the risks it encourages lead men into situations that often wound or kill them. And higher levels of testosterone-driven promiscuity make men more prone to sexually transmitted diseases. This is one reason that men live shorter lives on average than women. There is something, in other words, tragic about testosterone. It can lead to a certain kind of male glory; it may lead to valor or boldness or impulsive romanticism. But it also presages a uniquely male kind of doom. The cockerel with the brightest comb is often the most attractive and the most testosteroned, but it is also the most vulnerable to parasites. It is as if it has sacrificed quantity of life for intensity of experience, and this trade-off is a deeply male one.

The things that increase testosterone serum levels are things you should be doing anyway.

  1. ensure you're getting good quality sleep (poor quality sleep responsible for up to a 40% drop)
  2. ensure that your diet includes enough fresh vegetables that you're getting RDAs of zinc, magnesium, and b-vitamins.
  3. engage in physical activity, especially those that engage the largest muscle groups.
  4. stop eating low fat foods. the majority of people eating low fat food make up for the lack of calories with more sugary foods. whole milk, eggs, full fat cottage cheese, nuts are all good for you.
  5. decrease stress in your life. cortisol is bad for test levels. meditation has been shown to significantly reduce cortisol levels. this is one of the things sleep plays into as well.

I'm curious about your musings on the connection between masturbation and risk-taking. Would it be mediated by testosterone levels?

I've heard several people mention the idea that frequent masturbation would lower testosterone levels. But after a very brief search, I found claims that no studies supporting such a relationship exists, and a study (admittedly with few subjects) which failed to find any effects from sexual activity on blood plasma testosterone levels. Know any results to the contrary?

Would it be mediated by testosterone levels?

That was the obvious place to look for such connections, yeah, even before I went through the Eisenegger review; I already have a cite that fatherhood reduces testosterone levels.

From your modafinil link:

Interestingly, there seem to be some groups for which modafinil does little or nothing, and this ineffectiveness may not be due to counterfeit product or poor self-monitoring, but genetics:

“…Two-time 100 mg modafinil potently improved vigor and well-being, and maintained baseline performance with respect to executive functioning and vigilant attention throughout sleep deprivation in Val/Val genotype subjects but was hardly effective in subjects with the Met/Met genotype.”

The genotype variation specifically refers to the Rs4680 SNP, which is one of the SNPs that services like 23andMe test for.

Crap, I'm Met/Met! Thanks for saving me some money though.

You're welcome. You could get some and try anyway to see what happens - I've long wondered how reliable these SNP findings are.

I'm curious too. I did my MSc thesis on pharmacogenomics (pdf), and am now generally skeptical of this sort of result. I'll have a closer look at the paper and make a decision. Any tips on procurement if the decision goes that way?

Google Adrafinil. It works very well for me. It is legal and unregulated in USA and some other places.

Any tips on procurement if the decision goes that way?

Nothing that I haven't already written down or that a LWer shouldn't be able to figure out.


I am well aware of that site, have received modafinil from it, and have even corresponded with the owner; ignorance of specific websites was not the point I was making.

I just felt like the speed of my answer should still be of some benefit, and I wasn't aware that you had gained the knowledge of its existence in the month hence your previous comment.

So, ought we take supplemetary testosterone?

The benefits of weight training are typically significant and self-evident. Though anecdotal, most accounts I've heard (including my own) suggest that this is in large part due to increased testosterone levels. Why not supplement the natural process? If so, by how much?

So, ought we take supplemetary testosterone?

A question whose answer is far from obvious. See the homeostasis quote for one obstacle...

From Sullivan's article:

Testosterone's antidepressive power is only marginally understood. It doesn't act in the precise way other antidepressants do, and it probably helps alleviate gloominess primarily by propelling people into greater activity and restlessness, giving them less time to think and reflect. (This may be one reason women tend to suffer more from depression than men.) Like other drugs, T can also lose potency if overused. Men who inject excessive amounts may see their own production collapse and experience shrinkage of their testicles and liver damage.

Thank you for this excellent research.

It's nothing special; all I did was read a PDF and excerpt the bits I thought interesting.

In women, estrogen may be linked to power the way testosterone is in men.

A quick google couldn't find any link to the study itself, if you have a link, could you post it please?

That link does not talk the effects of estrogen...

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Estradiol is one of the estrogens.

Very useful info.

This is great!

Incidentally, apparently testosterone level tests are as low as $45.