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Fisherian runaway: Difference between revisions
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== Mechanism == | ==Explanation== | ||
=== Mechanism === | |||
[[File:Peacock courting peahen.jpg|alt=|thumb|"The females may be dull looking, but they're very picky." A peacock courting a peahen]] | [[File:Peacock courting peahen.jpg|alt=|thumb|"The females may be dull looking, but they're very picky." A peacock courting a peahen]] | ||
Females/males become more choosy about a heritable trait for the simple reason that other females/males find the trait attractive. As the selective pressure for females/males to prefer the trait increases so too does the selective pressure for females/males to produce the trait, creating a [https://en.wikipedia.org/wiki/Positive_feedback_loop positive feedback loop]. In response to the increased choosiness, males and females evolve to enlarge, overcomplicate or beautify that trait in efforts of becoming more attractive (larger dick size, larger breasts, etc.) The exponential nature of positive feedback loops leads to the inevitable conclusion, that the attractive trait eventually becomes comically unhealthy and [[Maladaptiveness|maladaptive]]. For example a man's dick becoming too long and large to fit inside the vagina, or a woman's breasts becoming so large and heavy the woman can no longer walk, and has to crawl, or be carried from point A to point B. These feedback loops in a stable environment do not become maladaptive for the entire species, because the comically unhealthy and [[Maladaptiveness|maladaptive]] individuals don't [[Reproductive success|reproduce]]. | Females/males become more choosy about a heritable trait for the simple reason that other females/males find the trait attractive. As the selective pressure for females/males to prefer the trait increases so too does the selective pressure for females/males to produce the trait, creating a [https://en.wikipedia.org/wiki/Positive_feedback_loop positive feedback loop]. In response to the increased choosiness, males and females evolve to enlarge, overcomplicate or beautify that trait in efforts of becoming more attractive (larger dick size, larger breasts, etc.) The exponential nature of positive feedback loops leads to the inevitable conclusion, that the attractive trait eventually becomes comically unhealthy and [[Maladaptiveness|maladaptive]]. For example a man's dick becoming too long and large to fit inside the vagina, or a woman's breasts becoming so large and heavy the woman can no longer walk, and has to crawl, or be carried from point A to point B. These feedback loops in a stable environment do not become maladaptive for the entire species, because the comically unhealthy and [[Maladaptiveness|maladaptive]] individuals don't [[Reproductive success|reproduce]]. | ||
== Initiation == | === Initiation === | ||
Such feedback loops can be initiated by arbitrary aesthetic selection, but also when a trait is slightly correlated with fitness (e.g. health), or when a trait is similar in appearance to attractive or otherwise valuable objects or body parts.<ref>Fuller, R. C., Houle, D., & Travis, J. 2005. ''Sensory Bias as an Explanation for the Evolution of Mate Preferences.'' [[https://www.jstor.org/stable/10.1086/444443 Abstract]], p. 444</ref> For example, women's breasts may have evolved to mimic their buttocks because the latter was already a sexually attractive body part before humans developed upright posture, and then Fisherian runaway may have lead to breasts becoming increasingly larger and increasingly attractive to men. | Such feedback loops can be initiated by arbitrary aesthetic selection, but also when a trait is slightly correlated with fitness (e.g. health), or when a trait is similar in appearance to attractive or otherwise valuable objects or body parts.<ref>Fuller, R. C., Houle, D., & Travis, J. 2005. ''Sensory Bias as an Explanation for the Evolution of Mate Preferences.'' [[https://www.jstor.org/stable/10.1086/444443 Abstract]], p. 444</ref> For example, women's breasts may have evolved to mimic their buttocks because the latter was already a sexually attractive body part before humans developed upright posture, and then Fisherian runaway may have lead to breasts becoming increasingly larger and increasingly attractive to men. | ||
Since females are [[Bateman's principle|more choosy]] in many species throughout the animal kingdom (including humans), the males tend to be more ornamented. | Since females are [[Bateman's principle|more choosy]] in many species throughout the animal kingdom (including humans), the males tend to be more ornamented. | ||
=== Sexy son hypothesis === | |||
The sexy son hypothesis in evolutionary biology and sexual selection—proposed by Ronald Fisher in 1930—states that a female's ideal mate choice among potential mates is one whose genes will produce male offspring with the best chance of [[reproductive success]]. | |||
This implies that the male's ability to provide is less important, especially in polygynous species (like humans are, moderately) where the lesser paternal investment must be outweighed by the benefit in reproductive success the female achieves through mating with an attractive male. She forgoes direct benefits (resources and protection) in exchange for indirect genetic benefits (greater reproductive success). Though these are not necessarily mutually exclusive, of course.<ref>https://academic.oup.com/beheco/article/19/2/456/214088</ref> | |||
{{#ev:youtube|https://www.youtube.com/watch?v=idc_XZpB0h0|frame|}} | |||
Since having sexy sons stems from women choosing the mate they are most physically attracted too, the male equivalent is doing the same thing (resulting in sexy daughters). However, men are typically [[bateman's principle|less choosy]] in regards to their standard in female looks (at least for relationships that require less investment). Males choosing women whom they were most physically attracted too, and could attain, having been the norm throughout human history, has resulted in the development of female ornamental traits designed to attract men. | |||
{{#ev:youtube|https://www.youtube.com/watch?v=kXrkgPgt234|frame|}} | |||
== Humans == | == Humans == | ||
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Beauty could have evolved simply by sexual selection, i.e. mate selection favoring objective [[beauty]] (simplicity). But feedback loops as mentioned above may have exaggerated aspects of it, leading to increased sexual dimorphism and amplified and narrowed the attraction to specific kinds of beautiful physical traits. This also stabilizes the phenotype, making it harder to adapt to environmental changes. Any sort of [[sexual dimorphism]], whether behavioral or ornamental likely tends to get reinforced by such feedback loops because [[sexual dimorphism]] is inherently attractive.<ref>https://incels.wiki/w/Scientific_Blackpill#Even_chickens_prefer_sexually_dimorphic_human_faces.2C_to_the_same_extent_as_humans</ref> | Beauty could have evolved simply by sexual selection, i.e. mate selection favoring objective [[beauty]] (simplicity). But feedback loops as mentioned above may have exaggerated aspects of it, leading to increased sexual dimorphism and amplified and narrowed the attraction to specific kinds of beautiful physical traits. This also stabilizes the phenotype, making it harder to adapt to environmental changes. Any sort of [[sexual dimorphism]], whether behavioral or ornamental likely tends to get reinforced by such feedback loops because [[sexual dimorphism]] is inherently attractive.<ref>https://incels.wiki/w/Scientific_Blackpill#Even_chickens_prefer_sexually_dimorphic_human_faces.2C_to_the_same_extent_as_humans</ref> | ||
==Criticism== | ==Criticism== | ||