> From: "Bethan Barnes" <BETHAN92@psy.soton.ac.uk>
> Date: Fri, 3 Mar 1995 15:54:34 GMT
> I was wondering after the discussion in yesterday's lecture about the
> ultimate aim of sex being reproduction, where does Darwin stand with
> regard to the paedophile? Clearly the paedophile cannot hope to
> reproduce with a pre pubescent child, so surely the ultimate aim in
> this instance is pleasure.
Remember my alert about not mixing up the proximal and the ultimate?
The ultimate aim of sexuality is reproduction; its proximal aim is
pleasure. In this respect, the paedophile example is the same as the
homosexual example I mentioned in class, and the Darwinian explanation
is similar in both cases.
Whenever you have an evolutionary "cue" (such as the size of the eyes,
for example), it is always possible to create an exaggerated
"superstimulus" out of it, one that satisfies the proximal detectors of
the cue, but at the expense of the ultimate causes that first shaped
them. The so-called "cute" cues -- huge eyes, big head in relation to
the body -- elicit the "oh isn't it cute" reaction, and the reaction
can be bigger for unnatural eye and head sizes that are actually
monsters than it is for real biological proportions. You can create an
artificial superstimulus for a stickle-back fish that it will prefer to
court over real members of its species by just exaggerating certain
features in the direction of an existing preference.
Remember the example I gave of children's selective appetite for sweets
and fat, which was adaptive in our Environment of Evolutionary
Adaptedness, where sugar and fat were rare, yet essential, but is now
merely an exaggerated preference for something that's not so good for
you? It used to be adaptive. Now, it's mildly maladaptive, but with
modern dentistry and dieting, it's not killing off those who have the
preference, so it's just there.
The story with paedophilia may be similar (at least
adult-male/female- child paedophilia): As you see in the Buss and
Kenrick/Keefe articles, human males have a tendency to prefer SOMEWHAT
younger mates, for Darwinian reasons. Just crank that up into a
"superstimulus" and you see where it might yield.
But because paedophilia is much rarer than addiction to sweets, there is
probably more to it than just a superstimulus effect. Many paedophiles
are probably sociopaths (see the Mealey article); and there is also the
fact that, because the Darwinian mechanism of "neotony" (also called
"paedogenesis," the prolonging of earlier developmental and even
embryological stages in the service of new adaptations) is such a
prominent feature of the human species, perhaps that leaves open the
possibility of becoming fixated on a cue that was "intended" for an
earlier stage of development (remember the ducklings that imprinted on
Lorenz -- and then wanted to mate only with human beings at maturity?).
Homosexuality is harder to explain. If it were just an exaggerated
bisexual preference, it could be explained as early fixation on
ambiguous androgynous cues, again a developmental fixation, and
then a superstimulus amplification effect. But if there really is a
subpopulation of the human species that is genetically disposed toward
exclusive homosexuality, then it, like left-handedness, is harder to
explain adaptively (though people have tried in both cases, producing
what I, at least, find rather silly "Just-So" stories; I've added
some Abstracts after this message).
> Also, with regard to this issue, many paedophiles claim maladaptive
> learning (or in other words the fact that they were abused themselves)
> as the reason that they themselves abuse. Does this mean that
> maladaptive learning can overide the genetic desire to reproduce?
Yes, of course it can. That's just the proximal over-riding the
ultimate (as in children's appetite for sweets). But there's always
something that has puzzled me about the transgenerational abuse
theories of paedophilia: They don't make sense in terms of the gender
statistics. It is my understanding that the vast majority of abusers
are males, and the majority of victims are younger females. How
could proportions like that pass themselves on from generation to
generation? You would have to predict some sort of oscillation, with
males abusing females for one generation, then females abusing
(males?), then vice versa again. If most abuse were male on male, then
the theory would have made sense, but as it is, there needs to be more
to it that just the abused-abuser hypothesis.
Here are some Abstracts of papers that have evolutionary theories about
about homosexuality, paedophilia and left-handedness.
Reproductive strategies and gender construction: An evolutionary view of
homosexualities. Homosexuality, Which Homosexuality? Conference (1987,
Journal of Homosexuality, 1993, v24 (n3-4):55-71.
ABSTRACT: Examined whether the historical occurrence of various forms of
homosexuality (HM) and bisexuality can be explained as part of the
management of reproduction in response to environmental conditions (ECs).
It is believed that explanations for the occurrence and forms of HM
appealing to genetics are biologically indefensible and historically
inadequate. However, Darwinian behavioral theory, specifically the life
history theory, provides an explanatory framework. An individual's life
course consists of behaviors coerced by parents and chosen by the
individual in response to ECs, forming a coherent reproductive strategy.
In the process, alternate male and female genders are explained, and the
normative male bisexuality of classical Athens and modern
Mediterranean/Latin societies is elucidated. The rise of modern HM in
industrial nations results from the demographic transition to low
mortality and low fertility.
Mihalik, Gary J.
From anthropology : Homosexuality, stigma, and biocultural evolution.
Special Section: Stigma and homosexuality.
Journal of Gay & Lesbian Psychotherapy, 1991, v1 (n4):15-29.
ABSTRACT: Discusses stigmatization of homosexuals from the standpoint of
neuropsychological functioning. One model of the processing of perceptual
and cognitive information uses descriptive axes composed of antonyms; this
is the basis of the "us-them" dichotomy that is an integral part of the
process of stigmatization. The development of the neocortex has made
greater cognitive and behavioral flexibility possible, releasing humans
from the rigid stimulus-response behavioral paradigm. There is a strong
positive correlation between psychological androgyny and the flexibility,
adaptability, and complexity of mental function. Homosexuals are more
psychologically androgynous than nonhomosexuals and are likely to
contribute significantly to the process of cultural evolution. Hampering
such evolution through continued stigmatization of homosexuals is
detrimental to the species.
Weinrich, James D.
Human reproductive strategy. I: Environmental predictability and
reproductive strategy; effects of social class and race. II: Homosexuality
and non-reproduction; some evolutionary models.
Dissertation Abstracts International, 1977 Apr, v37 (n10-B):5339.
Wilson, Glenn D., ed.
Variant sexuality: Research and theory. Johns Hopkins University Press;
Baltimore, MD, US, 1987.
ABSTRACT: (from the book) The study of sexual behaviour is a subject that
always attracts wide interest, but which is characterised more by
sensational stories in the media than by scientific analysis. With variant
sexuality and sexual deviation that is even more true. Some deviations,
such as fetishes, may be trivial or at times amusing, but others may lead
to horrific crimes. Although family forms of sexual behaviour such as
homosexuality are now more widely discussed, others such as paedophilia
are still largely taboo, and others may require clinical treatment....
This book presents contributions from major international authorities
reviewing major themes in variant sexuality, and presenting new research.
For example, there is evidence of neurological factors being identifiable
in exhibitionists, who can be distinguished from normals on the basis of
EEG responses to mental tasks. Genetic and evolutionary arguments are
presented for the preponderance of paraphilia in males. Freudian and
psychoanalytic theories are shown to have limited scientific explanatory
power. These and other topics are reviewed in a book that should interest
psychologists, biologists and psychiatrists in particular, as well as
others fascinated by the social, behavioural and biological aspects of
List of contributors.
Deviation and variation. Alex Comfort. (Chapter record available).
Genetic and hormonal factors in human sexuality: Evolutionary and
developmental perspectives. Raymond E. Goodman. (Chapter record
Cerebral aspects of sexual deviation. Pierre Flor-Henry. (Chapter record
An ethological approach to sexual deviation. Glenn D. Wilson. (Chapter
Logical models of variant sexuality. Vaclav Pinkava. (Chapter record
The phylogenetics of fetishism. Arthur W. Epstein. (Chapter record
Sexual deviation: Psychoanalytic research and theory. Paul Kline. (Chapter
A cross-cultural perspective on homosexuality, transvestism and
trans-sexualism. Frederick L. Whitam. (Chapter record available).
The courtship disorders. Ron Langevin and Reuben A. Lang. (Chapter record
The sadomasochistic contract. Christopher C. Gosselin. (Chapter record
ABSTRACT: (from the cover) (The authors) analyze current research on asymmetry
Springer, Sally P.; Deutsch, Georg.
Left brain, right brain (4th ed.). W. H. Freeman & Co, Publishers; New
York, NY, US, 1993.
ABSTRACT: (from the cover) (The authors) analyze current research on asymmetry
in brain-damaged, split-brain, and normal Subjects, and explore its
implications for human behavior.
(from the publicity materials) (This book presents) information on:
(left-handedness) and mortality; the role of hormones on sex differences
in cognition; "handedness" in non-human primates; how the concept of
"hemisphericity" has been applied and misapplied; "natural" split brains
or agenesis of the corpus callosum; developmental disabilities and
asymmetry; the promise and limitations of neuroimaging; the newest views
on memory and perception; hemispheric differences and emotion; issues of
mind-brain relationships (and) left brain/right brain programs in business
management and creativity seminars.
Early evidence from the clinic: The discovery of asymmetry.
The human split brain: Surgical separation of the hemispheres.
Asymmetries in the normal brain.
Measuring the brain and its activity: Physiological correlates of
The puzzle of the left-hander.
Further evidence from the clinic: Aphasia, apraxia, agnosia.
Further insights from the clinic: Neglect, amnesia, music, and emotion.
Sex and asymmetry.
Phylogeny and ontogeny: The evolution and development of asymmetry.
Asymmetry's role in developmental disabilities and psychiatric illness.
Hemisphericity, education, and altered states.
Concluding hypotheses and speculations.
Appendix: Functional neuroanatomy: A brief review.
McManus, I. C.; Bryden, M. P.
Handedness on Tristan da Cunha: The genetic consequences of social
isolation. International Journal of Psychology, 1993 Dec, v28 (n6):831-843.
ABSTRACT: Examined the suggestion by K. A. Provins (see PA, Vol 78:514) that
the apparently low incidence of left-handedness on the island of Tristan
da Cunha (TDC) is the result of social pressures such as deference to
authority and group conformity, and that "any genetic factor determining
left-handedness must be very weak." The authors used 10,825 Monte Carlo
simulations of the growth of the population of TDC from 1827 to 1961, to
show that if the original population was randomly selected from a large
population with a typical gene-frequency, then a combination of founder
effects, genetic drift, and evolutionary bottlenecks can readily explain
the low incidence of left-handedness that was found. Indeed, in 15% of the
simulations the C allele, which is postulated to be responsible for
left-handedness, has disappeared, resulting in a population with no
left-handers. The data from TDC are therefore compatible with a genetic
model of left-handedness. (French abstract)
Hopkins, W. D.; Bard, K. A.; Jones, A.; Bales, S. L.
Chimpanzee hand preference in throwing and infant cradling: Implications
for the origin of human handedness.
Current Anthropology, 1993 Dec, v34 (n5):786-790.
ABSTRACT: Responds to W. H. Calvin's (1983) hypothesis that right-handed
throwing in humans has evolved as a result of a left-hemisphere
specialization for planned sequential movements, and that it has been more
predominant in females due to infant carrying on the left arm.
Observations of throwing were made on 36 chimpanzees to see whether
nonhuman primates exhibit population level hand preference. 24 Subjects
were categorized as right-handed, 9 as left-handed, and 3 as ambidextrous.
Observations of infant cradling were made on 12 captive mother-infant
pairs of chimpanzees. Seven mothers exhibited a left-side bias and 5
exhibited a right-side bias; however, infants favored hand preferences
opposite to their mothers' cradling preferences. These data partially
support Calvin's hypothesis; handedness may have been influenced by
evolutionary selection for throwing. However, this effect is neither
specific to homonid evolution, nor especially pronounced in females.
Corballis, Michael C.
Laterality and human evolution.
Psychological Review, 1989 Jul, v96 (n3):492-505.
ABSTRACT: The question of whether there is a fundamental discontinuity between
humans and other primates is discussed in relation to the predominantly
human pattern of right-handedness and left-cerebral representation of
language. Both phenomena may go back at least to Homo habilis, 2-3 million
years ago. However, a distinctively human mode of cognitive representation
may not have emerged until later, beginning with H. erectus and the
Acheulean tool culture about 1.5 million years ago and culminating with H.
sapiens sapiens and rapid, flexible speech in the last 200,000 years. It
is suggested that this mode is characterized by generativity, with
multipart representations formed from elementary canonical parts (e.g.,
phonemes in speech, geons in visual perception). Generativity may be
uniquely human and associated with the left-cerebral hemisphere. An
alternative, analogue mode of representation, shared with other species,
is associated with the right hemisphere in humans.
MacNeilage, Peter F.; Studdert-Kennedy, Michael G.; Lindblom, Bjorn.
Primate handedness reconsidered.
Behavioral & Brain Sciences, 1987 Jun, v10 (n2):247-303.
Pub type: Literature Review; Review.
ABSTRACT: Discusses population-level hand use asymmetries in nonhuman primates.
Studies indicating left-hand preferences for reaching and right-hand
preferences for manipulation and practiced performance in stereotyped
situations are reviewed. It is argued that previous negative conclusions
on preferences were due to methodological problems (e.g., failure to
emphasize serial trends). Primate handedness patterns are believed to have
evolved with adaptations to feeding and to be precursors of human
hemispheric specialization patterns. It is suggested that left-hand
specialization evolved with the prehensile hand, followed by evolution of
right-hand specialization with the development of the opposable thumb. 25
commentaries and a response to those commentaries by the authors are
MacNeilage, Peter F.
The "postural origins" theory of primate neurobiological asymmetries.
IN: Biological and behavioral determinants of language development.; Norman
A. Krasnegor, Duane M. Rumbaugh, Richard L. Schiefelbusch, Michael
Studdert-Kennedy, Eds. Lawrence Erlbaum Associates, Inc, Hillsdale, NJ, US.
1991. p. 165-188.
ABSTRACT: (from the book) discusses a theory of how cerebral hemispheric
specialization evolved in primates; argues that asymmetries in cerebral
function emerged due to an adaptation of posture in the aboreal habitat of
early primates; postulates that both handedness and communicative capacity
become dependent on " ...whole-body postural organization"; asserts that
validity of the theoretical position hinges in part upon the observation
that "human footedness, a necessarily postural specialization, has a
stronger contralateral relation to language specialization in humans than
does handedness; evidence for the theory is reviewed in the context of
studies that indicate a preference for left-hand-right-hemisphere
specialization of visually guided reaching and a corresponding
right-side-left-hemisphere postural control specialization in primates;
reviews the implications of his theory for the ontogenesis of language.
Corballis, Michael C.
The lopsided ape: Evolution of the generative mind. Oxford University
Press; New York, NY, US, 1991.
ABSTRACT: (from the jacket) In "The Lopsided Ape," Corballis takes us on a
fascinating tour of the origins and implications of the specialization of
the two halves of the brain--known as laterality--in human evolution. He
begins by surveying current views of evolution, ranging from the molecular
level--the role of viruses, for instance, in transporting genes between
species--to the tremendous implications of such physical changes as
walking on two feet.... Corballis argues that the evolution of the
brain--and language--was intimately tied up with these changes: The
proliferation of objects made by early hominids, in an increasingly
artificial environment marked by social cooperation, demanded greater
flexibility in communication and even in thinking itself. These
evolutionary pressures spurred the development of laterality in the brain.
He goes on to look at the structure of language, following the work of
Noam Chomsky and others, showing how grammar allows us to create an
infinite variety of messages. In examining communication between animals
and attempts to teach apes and dolphins language, he demonstrates that
only humans have this unlimited ability for expression--an ability that he
traces back through hominid evolution. After this engrossing account of
what we know about evolution, language, and the human brain, Corballis
suggests that the left hemisphere has evolved a Generative Assembling
Device, a biological mechanism that allows us to manipulate open-ended
forms of representation and provides the basis for mathematics, reasoning,
music, art, and play as well as language and manufacture. It is this
device, he writes, that truly sets us off from the apes.... Both a
detailed account of human language and evolution and a convincing argument
for a new view of the brain, "The Lopsided Ape" provides fascinating
insight into our origins and the nature of human thought itself.
Are humans unique?
The human condition.
The evolution of language.
Language and the brain.
Praxis and the left brain.
The generative mind.
The duality of the brain.
The plastic brain.
Macneilage, Peter F.
The evolution of hemispheric specialization for manual function and
IN: Higher brain functions: Recent explorations of the brain's emergent
properties. Wiley series in neurobiology.; Steven P. Wise, Ed. John Wiley
& Sons, New York, NY, US. 1987. p. 285-309.
ABSTRACT: (from the chapter) reevaluation of the evolution of hemispheric
specialization for language and its relation to hemispheric specialization
for manual function... characterization of the nature of language form...
functional discontinuity between hominids and other primates in language,
in handedness, and in the left hemispheric specializations related to
both... ways in which language and manual actions are functionally
related, which may have important implications.
This archive was generated by hypermail 2b30 : Tue Feb 13 2001 - 16:23:16 GMT