[Fis] Emergence of Human Sexual Behaviour

[Rainer Feistel (IOW)]

> Dear Steve,
>
> Thank you for your quick response, your careful reading, and 
> encouraging comments with which, including the more critical ones, I 
> may fully agree. You raised a number of non-trivial points. However, I 
> cannot provide any rigorous proofs you are asking for, but merely a 
> “scaffolding” working hypothesis. In the Spanish film “Jamon, jamon” 
> the girl is asking her boyfriends why they do what they do with her 
> body. In fact, the boys had no idea except that they just enjoyed 
> doing that. I guess that most men all over the world instinctively 
> share their kind of behaviour, suggesting that this is commonly 
> inherited from a distant past. In my narrative and related paper, I 
> just speculate from where such courtship habits may have originated, 
> apparently being encoded in our genes. It is habit of use that 
> specifies the meaning of arbitrary symbols, as already Charles Peirce 
> had emphasised.
>
> (i)It is correct that my suggested scenario is a succession of 
> critical turnarounds, so that the entire staircase will break down as 
> soon as a single step underway is missed. No step appears plausible 
> without the preceding one, each step does not solve the problem but 
> urgently requires the next step until some final one. This is 
> intentionally so rather than representing a deficiency of the model. 
> Fossils have shown that hominin evolution in the past several million 
> years was a tree with numerous branches of which virtually all 
> disappeared except our direct ancestors. Low reproduction rate is a 
> crucial selective value; hominins that failed to find the next step of 
> the staircase suffered from subcritical reproduction rates and got 
> extinct. Likely, only one line successfully managed the entire risky 
> parcours, starting at challenging bipedalism and ending at safe 
> surplus multiplication with emigration pressure: our ancestors. No 
> stagnant survival possible in between, so the idea that violent 
> selective pressure enforced the (necessarily speedy) evident hominin 
> sexual revolution (rather than gradual sexual selection).
>
> (ii)I prefer to argue that any kind of information may be classified 
> into either “structural information” or “symbolic information”. Any 
> form of physical interaction necessarily transfers structural 
> information between the interacting objects, without purpose, 
> predictive intention or the need of symbols. Looking into the sky, the 
> light of a star carries structural information that arrives at our 
> eye. Our sensor cells convert this structural information into 
> symbolic information in a “symbolisation” process: representative 
> standard nerve pulses as symbols are generated, communicated, stored 
> and processed with purpose and intention. By natural evolution, 
> symbolic information emerged from the structural one by 
> “ritualisation” transitions. Shannon entropy refers to symbolic 
> information, Pauling entropy to structural information. More details 
> at, say, “Self-Organisation of Prediction Models”, 
> https://urldefense.com/v3/__https://doi.org/10.3390/e25121596__;!!D9dNQwwGXtA!XuI2mMrOQpdQkGnDLYOWh1_yq9UHSIM89MEBqvBJUyMMuX0YWG3N0xeiZFQkOtsKn2wmbxTXGL6aLsomEjDC-7LNJUk$  , and “Emergence of Symbolic 
> Information by the Ritualisation Transition”, 
> https://urldefense.com/v3/__https://doi.org/10.1142/9789813109001_0004__;!!D9dNQwwGXtA!XuI2mMrOQpdQkGnDLYOWh1_yq9UHSIM89MEBqvBJUyMMuX0YWG3N0xeiZFQkOtsKn2wmbxTXGL6aLsomEjDC_uoBcak$ 
>
> (iii)“Alternative hypotheses—fat storage byproduct, honest signal of 
> reproductive value, sexual selection, pair-bond reinforcement”: May or 
> may not be so. Common but vague and unspecific arguments. If so, why 
> do not chimp females exploit sexy breasts? By contrast, my argument 
> applies specifically to coercive mating of hominins. And to mammary 
> glands only. And supports contraception in order to protect toddlers 
> after weaning. It even explains, in the subsequent step, the 
> mysterious, cumbersome sexual interest of men in female nipples.
>
> (iv)“deceptive signals are often evolutionarily unstable”, and so also 
> here, as all the steps of the chain of transitions are unstable and 
> are dynamically replaced by their particular following step. The 
> lactation fake by adipose breast will sooner or later be revealed by 
> the next move of male behaviour: inspecting breast and nipples 
> visually, manually or orally.
>
> (v)There is little doubt that contraception implies futile ovulation 
> and menstruation instead of pregnancy. For the menopause, I have 
> borrowed the ovary exhaustion argument from Wallace and Kelsey (2010), 
> https://urldefense.com/v3/__https://doi.org/10.1371/journal.pone.0008772__;!!D9dNQwwGXtA!XuI2mMrOQpdQkGnDLYOWh1_yq9UHSIM89MEBqvBJUyMMuX0YWG3N0xeiZFQkOtsKn2wmbxTXGL6aLsomEjDC0F0JuLY$  . It does not only 
> support the grandmother hypothesis, it may also explain why humans 
> find young females sexy, quite in contrast to chimps who typically 
> ignore young females. As far as I know, chimps have post-reproductive 
> lives typically in captivity.
>
> (vi)Subcritical reproduction rates result from early weaning of 
> mothers with their sole responsibility for the helpless offspring 
> during childhood. To overcome this, other group members (preferably 
> females such as sisters or mothers) must assist in childcare when the 
> mother gives another birth too early. I prefer menopause and infertile 
> grandmothers as plausible candidates, produced by preceding 
> contraception and regular menstruation. I do not believe that male 
> chimps, as had elsewhere been suggested, which neither know about 
> their paternity nor are involved in any childcare, suddenly turn into 
> caring fathers who even voluntarily refrain from sex with the fertile 
> attractive mother after weaning.
>
> (vii)Proper investigation of human sexual behaviour is far beyond my 
> expertise. I merely review the published sex life of chimps from a 
> special perspective. I just imagine a fictitious scenario of the 
> effect of bipedalism on the reproduction behaviour of earliest 
> hominins, and the hypothetical emergence of novel sex symbols as a 
> consequence. Even this seems to appear, though, already as politically 
> provocative to radical feminists.
>
> (viii)I believe that my narrative is rather distinct from the typical 
> approaches in the anthropogenic literature, such as sexual selection 
> that gently transformed wild chimp hordes into harmonic 
> mother-father-child families. I am convinced that hominins were often 
> at the brink of extinction. Radical changes of reproduction (and 
> other) behaviour went along with frequent population bottlenecks and 
> enforced evolutionary progress at high speed. In order to support or 
> disprove my model, it may hopefully inspire experts of the various 
> fields involved to take a different look at their facts and models.
>
> Rainer
>
> -------- Weitergeleitete Nachricht --------
>
> *Betreff: *
>
> 	
>
> Re: [Fis] Emergence of Human Sexual Behaviour
>
> *Datum: *
>
> 	
>
> Thu, 12 Feb 2026 11:40:27 +0000
>
> *Von: *
>
> 	
>
> Steve Watson <sw10014 at cam.ac.uk>
>
> *An: *
>
> 	
>
> Rainer Feistel (IOW) <rainer.feistel at iow.de>, fis at listas.unizar.es 
> <fis at listas.unizar.es>
>
> Dear Rainer
>
> Thank you for initiating this stimulating discussion. Your narrative 
> on the emergence of human sexual behaviour is ambitious in scope and 
> admirable in its integrative intent. By placing ritualisation at the 
> centre of symbolic emergence and embedding human sexuality within a 
> biosemiotic framework, you invite precisely the kind of 
> cross-disciplinary dialogue that Foundations of Information Science 
> aims to foster.
>
> I would like to offer several reflections, structured around (1) the 
> conceptual strength of your approach, (2) empirical considerations, 
> and (3) theoretical implications concerning information and symbol 
> formation.
>
> First, regarding ritualisation as a mechanism of symbol emergence: 
> your use of ritualisation—following Julian Huxley’s ethological 
> work—as a transition from use-activity to signal-activity is 
> theoretically compelling. This move situates symbolic forms not as 
> sudden inventions, but as emergent transformations of already 
> functional behaviours. Symbols, in this view, crystallise from 
> repeated behavioural coordinations under selective pressures. That 
> conceptual continuity between biological function and informational 
> form is one of the strongest elements of your argument.
>
> Applying this mechanism to human courtship behaviour—especially the 
> proposal that inspection behaviours could have undergone 
> ritualisation—represents an interesting and creative extension of 
> ethological theory into anthropogenesis.
>
> However, several elements of the specific evolutionary narrative raise 
> questions concerning evidentiary robustness.
>
> One issue concerns the adaptationist chain structure of the argument. 
> The scenario is constructed as a sequential causal series: bipedalism 
> leads to earlier weaning; earlier weaning increases infant risk; this 
> selects for suppression of fertility swelling; persistent male 
> interest follows; coercion dynamics emerge; permanent adipose breasts 
> function as deceptive lactation signals; inspection behaviours are 
> ritualised; contraception produces futile ovulation and menstruation; 
> ovarian depletion lowers menopause age; grandmothering increases 
> reproductive success; demographic expansion follows.
>
> Each link may be plausible in isolation. Yet when combined into a 
> single linear chain, the explanatory burden becomes very high. If one 
> step is weakened, the dependent steps become unstable. Evolutionary 
> history is often more reticulate and multi-causal than such linear 
> reconstructions suggest. Clarifying which steps are essential to the 
> thesis and which are heuristic would strengthen the model.
>
> A particularly delicate component is the hypothesis that permanent 
> adipose breasts evolved primarily as anti-coercion deceptive signals. 
> Signalling theory suggests that deceptive signals are often 
> evolutionarily unstable unless constrained by costs or enforcement 
> mechanisms. Alternative hypotheses—fat storage byproduct, honest 
> signal of reproductive value, sexual selection, pair-bond 
> reinforcement—remain active and empirically viable. At present, the 
> evidence does not decisively privilege the anti-coercion account. The 
> proposal would benefit from explicit, discriminating predictions that 
> could in principle falsify it.
>
> Similarly, the suggestion that successful contraception led to futile 
> ovulation and regular menstruation is innovative but currently lacks 
> strong mechanistic support. Evolutionary explanations of menstruation 
> remain contested and diverse. A clearer account of physiological 
> pathways would be necessary to substantiate this connection.
>
> With respect to menopause and the grandmother effect, while there is 
> meaningful support for grandmothering hypotheses, the topic remains 
> debated. Moreover, recent primate research complicates sharp contrasts 
> between humans and chimpanzees regarding post-reproductive lifespan. 
> Thus, integrating menopause into the scenario is conceptually elegant 
> but empirically provisional.
>
> From an information-scientific perspective, further clarification may 
> also be helpful. When describing breasts or swellings as “sex symbols” 
> or “information tools,” it is important to specify what is meant by 
> information. Is it conceived in a Shannon-type transmission sense, a 
> functional selection sense, or a relational coordination sense? The 
> narrative occasionally risks reifying symbols as objects that carry 
> information, rather than describing them as stabilised patterns of 
> interaction within coupled organisms. Emphasising the relational 
> dimension of signalling may strengthen theoretical coherence within 
> the Foundations of Information Science context.
>
> Finally, the text connects deep evolutionary dynamics to contemporary 
> phenomena such as sexual harassment, divorce rates, and declining 
> birth numbers. While exploring long-term behavioural legacies is 
> legitimate, caution is warranted. Contemporary sexual behaviour is 
> deeply shaped by cultural, economic, institutional, and technological 
> factors. Any evolutionary inheritance operates within these 
> higher-order symbolic systems. Distinguishing between speculative 
> evolutionary predispositions and modern socio-cultural dynamics would 
> enhance explanatory precision and avoid unintended normative implications.
>
> In conclusion, your scenario is bold, integrative, and intellectually 
> generative. Its strength lies in provoking dialogue and in 
> foregrounding ritualisation as a mechanism for the emergence of 
> symbolic coordination. At present, however, the evidentiary 
> scaffolding appears insufficient to support the full sequential model 
> as more than a plausible reconstruction. Clarifying empirical 
> commitments, alternative hypotheses, and falsifiable predictions would 
> significantly strengthen the contribution.
>
> I look forward to further discussion.
>
> With collegial regards,
>
> Steve Watson
>
>
> -- 
> Note: New Email Address:rainer.feistel at iow.de
> Dr. rer. nat. habil. Rainer Feistel
> Physicist (emeritus)
> PS Gustav Hertz Prize, Berlin 1981
> CITAC Best Paper Award, Paris 2011
> IAPWS Honorary Fellow, London 2013
> BIPM Metrologia Highlight Articles, Paris 2016
> EGU Fridtjof Nansen Medal, Vienna 2018
> LS Daniel Ernst Jablonski Medal, Berlin 2021
> IAPWS Gibbs Award, Boulder, Co., 2024

-- 
Note: New Email Address:rainer.feistel at iow.de
Dr. rer. nat. habil. Rainer Feistel
Physicist (emeritus)
PS Gustav Hertz Prize, Berlin 1981
CITAC Best Paper Award, Paris 2011
IAPWS Honorary Fellow, London 2013
BIPM Metrologia Highlight Articles, Paris 2016
EGU Fridtjof Nansen Medal, Vienna 2018
LS Daniel Ernst Jablonski Medal, Berlin 2021
IAPWS Gibbs Award, Boulder, Co., 2024
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