[Fis] Emergence of Human Sexual Behaviour

[Francesco Rizzo]

Dear Rainer,
The following proposition, excerpted from your brilliant introduction—(...)
This is a speculative narrative about how the ritualization of human sexual
behavior was likely caused by the transition to bipedalism. The genetic
heritage of those ancient times may still influence the social behavior of
modern humans and may be part of contemporary sexual conflicts, such as
sexual harassment, high divorce rates, or declining birth rates in liberal
societies. (...)—stimulates me to affirm—confirm your conception in light
of my New Economy based on the theory of value—love, value-art, and
value-beauty: a triad founded on existential and cognitive emo-rationality.
Thank you and best wishes.
Francesco.
Caro Rainer,
la seguente proposizione stralciata dalla tua brillante  introduzione - *(...)
Questa è una narrazione speculativa su come la ritualizzazione del
comportamento sessuale umano sia stata probabilmente causata dalla
transizione all'andatura bipede. Il patrimonio genetico di quei tempi
antichi potrebbe ancora influenzare il comportamento sociale degli esseri
umani moderni e potrebbe essere parte dei conflitti sessuali contemporanei,
come le molestie sessuali, gli alti tassi di divorzio o il calo delle
nascite nelle società liberali.(...)-* mi stimola ad affermare-confermare
la tua concezione alla luce della mia Nuova economia basata sulla teoria
del valore- amore, valore-arte e valore-bellezza: triade fondata sulla
emo-ra-zionalità esistenziale e cognitiva.
Grazie e auguri.
Francesco.


Il giorno gio 12 feb 2026 alle ore 11:08 Rainer Feistel (IOW) <
rainer.feistel en iow.de> ha scritto:

>
> *FIS: Foundations of Information Science* (https://urldefense.com/v3/__https://fis.sciforum.net/__;!!D9dNQwwGXtA!VAw3pR8Nrbzg_T1l0Xb3p0Nf67Q__59wpE8wvQybBcPScQNtZgHjKII6wR079GbwR-YPzJGH2OEYQ0CTzwY8KvjZV3wi$ 
> <https://urldefense.com/v3/__https://fis.sciforum.net/__;!!D9dNQwwGXtA!TC2CF1FSxOwksszfRibYo-j0C5j9X5Cs5vqGu7HETa00ZgkgNYYHGXR8xptIeqtIIXPKzi_jI3a9XLFc541ei259VdY$>)
>
>
> Discussion kickoff narrative by Rainer Feistel, 11 Feb 2026
>
> *Emergence of Human Sexual Behaviour*
>
> Natural evolution invented symbols as information carriers, universally
> exploited by any living being in various forms. As a rule, self-organised
> symbols appear by ritualisation, a qualitative transition from behavioural
> use-activities to related signal-activities, as discovered by Julian Huxley
> in 1914. Numerous novel and unparalleled symbols emerged in the course of
> anthropogenesis. Sex symbols, or courtship habits, are typically
> unambiguous intra-species information tools, governing the species’
> reproduction behaviour by starting and terminating the mating season.
>
> Permanent adipose mammary glands recognised as sex symbols are unique to
> humans only. If those emerged by a ritualisation transition, what may have
> been the use activity they had originated from? Anatomically, the most
> likely such activity is breastfeeding. However, lactating female mammals
> are generally infertile and typically avoid any mating activities in favour
> of their childcare. “The verdict is still out on why the permanent breast
> evolved in humans” wrote Deena Emera yet in 2024.
>
> Fossil and genetic evidence is consistent with the plausible hypothesis
> that the last common ancestor (LCA) of humans and great apes lived about 7
> million years ago and was similar to recent chimpanzees. The sexual
> behaviour of the latter, however, is very distinct from that of humans.
> Female chimps breastfeed their offspring, carried on their back, for about
> five years. Premature weaning poses a high lethal risk to the helpless
> infant. After weaning, females develop a prominent anogenital swelling as a
> sex symbol that invites males to mate. It is exclusively then that males
> show relevant sexual interest, and preferably in old “ugly” females. How
> may human sex life have evolved from such foreign roots during a relatively
> short period of history? Likely, the radical change was enforced by violent
> selective pressure.
>
> When the LCA gradually turned to bipedalism, carrying older, heavier
> infants on the back became impractical and weaning occurred earlier, with
> increasing risks for the offspring and generally reduced reproduction
> rates. Females suppressing the fertility swelling protected the toddler by
> preventing early pregnancy. Males responded with permanent sexual interest
> also in non-swollen females. Females reacted with repulsive frigidity,
> males in turn with coercive mating. Already from a distance, ostentatious
> adipose breasts, perfectly imitating lactating ones, prevented coercive
> male approaches, who in return started closer visual, manual or oral
> inspection of the nipples in order to check fertility and reveal the
> possible fake. Successful contraception by fertile females caused periodic
> futile ovulation and subsequent regular menstruation. The resulting ovary
> depletion lowered the menopause age into the lifespan, so that old females
> became infertile and could take care of their grandchildren when the mother
> became pregnant too soon. This grandmother effect raised the reproduction
> rate substantially, supporting enhanced migration pressure on the younger
> generation. The previous inspection of female nipples and genitals was no
> longer a necessary use-activity and turned into a courtship habit of humans
> by a ritualisation transition, similar to that of waterfowls originally
> discovered by Huxley.
>
> This is a speculative narrative of how the ritualisation of human sexual
> behaviour was possibly caused by the transition to bipedal gait. The
> genetic heritage of those old days may still influence the social behaviour
> of modern humans and may be part of contemporary sexual conflicts, such as
> sexual harassment, high divorce rates or declining birth numbers in liberal
> societies. Causal mental models are key for understanding the origin of
> such problems rather than just lamenting and deprecating their symptoms.
> Finding suitable compromises between mutually inconsistent sexual interests
> may provide a challenging but promising future solution, rather than
> implementing restrictive, one-sided patriarchal or matriarchal social
> suppression systems.
>
> *Further reading*:
>
> Feistel, R. (2025): Bipedalism, childhood, and ritualisation of human
> sexual behaviour: A hominin model scenario of ontogenetic selection.
> BioSystems 257, 105598. *https://urldefense.com/v3/__https://doi.org/10.1016/j.biosystems.2025.105598__;!!D9dNQwwGXtA!VAw3pR8Nrbzg_T1l0Xb3p0Nf67Q__59wpE8wvQybBcPScQNtZgHjKII6wR079GbwR-YPzJGH2OEYQ0CTzwY8Ks6RH6yP$ 
> <https://urldefense.com/v3/__https://doi.org/10.1016/j.biosystems.2025.105598__;!!D9dNQwwGXtA!TC2CF1FSxOwksszfRibYo-j0C5j9X5Cs5vqGu7HETa00ZgkgNYYHGXR8xptIeqtIIXPKzi_jI3a9XLFc541eOyxoBfw$>*
>
> Feistel, R. (2023): On the Evolution of Symbols and Prediction Models.
> Biosemiotics 16, 311–371. https://urldefense.com/v3/__https://doi.org/10.1007/s12304-023-09528-9__;!!D9dNQwwGXtA!VAw3pR8Nrbzg_T1l0Xb3p0Nf67Q__59wpE8wvQybBcPScQNtZgHjKII6wR079GbwR-YPzJGH2OEYQ0CTzwY8Kj0zFOsQ$ 
> <https://urldefense.com/v3/__https://doi.org/10.1007/s12304-023-09528-9__;!!D9dNQwwGXtA!TC2CF1FSxOwksszfRibYo-j0C5j9X5Cs5vqGu7HETa00ZgkgNYYHGXR8xptIeqtIIXPKzi_jI3a9XLFc541eNp-bGc4$>
>
>
>
>
> --
> Note: New Email Address: rainer.feistel en 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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