Scientists reveal why incest revolts
Sydney Feb 15 (ANI): Revulsion and
taboo against sex with family members is a natural
instinct and isn't taught, say US researchers,
whose findings challenges some basic tenets of
psychologist Dr Leda Cosmides from the University
of California Santa Barbara and colleagues report
their findings in today's issue of the journal
"We went in search of a kin
detection system because some of the most
important theories in evolutionary biology said
such a thing should exist," Cosmides was quoted by
ABC online, as saying.
"It should regulate
both altruism and incest disgust." The research
team found that humans have an inbuilt system that
"[Our] data shows that the
degree to which we feel those things is governed
by these cues that, for hunter-gatherers, predict
whether somebody is a sibling. And it works
regardless of your beliefs - who you are told who
your siblings are," she says.
her colleagues tested 600 volunteers, asking them
all sorts of questions jumbled together so they
would not know what was being studied.
asked them how many favours did you do for this
particular sibling in a month. We asked if this
sibling needed a kidney, how likely would you be
to donate this sibling a kidney."
asked about all sorts of ethical dilemmas,
including questions about sexual relationships
Among the volunteers were
people who had never shared a home with their
siblings - for instance, full- or half-siblings
born 10 or even 20 years apart.
determined incest disgust and altruism was the
same - how much time an older sibling spent
watching his or her mother care for a younger one,
or how much time the two spent together in the
"If you co-resided with
them for a long time as a child, you'd treat them
as you'd treat any full sibling. This seems to
operate non-consciously," Cosmides says.
Especially strong was the effect of
watching one's mother care for a younger child.
"They would be very altruistic towards
that baby and they'd be grossed out at the idea of
sex with that baby as an adult," Cosmides says.
She says women are especially sensitive to
"One whiff of possible siblinghood
and that's it for you if you are a woman," says
The study contradicts the
teachings of Sigmund Freud, who described Oedipal
urges and conflicts, Cosmides says.
thought you are attracted to your relatives and
your siblings and parents and it takes the force
of culture and society to keep you from committing
the incest that is in your heart," she says.