“Well, don’t you think that people who live in large urban areas, who travel and read and speak other languages are better able to make informed choices?”
"Norway rats have been bred in scientific laboratories since the middle
nineteenth century. Artificial selection has elicited-partly
through unconscious choices by laboratory personnel-a strain of rats
that is calmer, tamer, less aggressive, more fertile, and with significantly
smaller brains than their wild ancestors. All this is a convenience
for those experimenting on rats.
In a now-classic experiment, the psychologist John B. Calhoun let
Norway rats reproduce in an enclosure of fixed size until the number
of occupants, and therefore the population density, was very high. He
made sure, however, to provide everyone with enough to eat. What
happened?
As the population increased, a range of unusual behavior was
noted. Nursing mothers became somehow distracted, rejecting and
abandoning their infants, who would wither away and die. Despite the
surplus of ordinary food, the bodies of the newborn would be greedily
eaten by passersby. An adult female in heat or estrus would be pursued
relentlessly, not by one, but by a pack of males. She had no hope
of escape, or even sanctuary. Obstetrical and gynecological disorders
proliferated, and many females died giving birth, or from complications
soon after. When crowded together, the rats lost their inclination
or ability to build nests for themselves and their young; their desultory
constructions were amateurish and ineffective.
Among the males Calhoun distinguished four types: the dominant,
highly aggressive ones who, although "the most normal," would occasionally
go "berserk"; the homosexuals who made sexual advances
to adults and juveniles of both sexes (but, significantly, only to non ovulating
females): their invitations were generally accepted, or at
least tolerated, but they were frequently attacked by the dominant
males; a wholly passive population that "moved through the community
like somnambulists" with nearly complete social disorientation;
and a subgroup Calhoun calls the "probers," uninvolved in the struggle
for status but hyperactive, hypersexual, bisexual, and cannibalistic.
(from Carl Sagan and Ann Druyan-Shadows of Forgotten Ancestors 1992 pages 184-185)
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http://216.239.39.100/search?q=cache:vjj8FGZBelYC:luna.cas.usf.edu/~miles/belchpt9.htm+%22behavioral+sink%22&hl=en&ie=UTF-8 Animal study: Calhoun and the behavioral sink …. In his study rats were placed in a "perfect" environment, had adequate resources and were allowed to reproduce freely. The cage was designed so that 2 of the 4 rooms had only one entrance/exit, while the other 2 rooms had 2 entrances/exits. What happened was that in the 2 rooms with limited entrance/exit, a dominant male was able to maintain reasonable order, with limited crowding, normal feeding, socialization, and breeding. In the two rooms with multiple entrances/exits, no single male was able to maintain a normal dominance hierarchy, high density occurred, social order broke down, 4 classes of males developed (including marginally normal dominants, pansexuals, passive neutrals, and probers who were "hyperactive, hypersexual, homosexual/cannibals") and two classes of females (one abnormal in almost all manner, and the other marginally normal) occurred. Total chaos occurred in rooms 2 and 3. ….Would humans, if faced with such density levels act the same way?
Excellent post. Quite interesting, and would explain much if it holds true in more general form. Thanks!