Delte hjerner er klogere
Jesus-loves-you
>
> Subject: Menneskets store- og lille-hjerne
> 09481 news:4a8faec5$0$298$1472...@news.sunsite.dk
> http://groups.google.dk/group/dk.videnskab/msg/b00c21c815440a72
> >
> > apropos "bj�lken" mellem h�jre- og venstre-hjernehalvdel !!!
Videnskaben.dk skriver ...
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Delte hjerner er klogere
En ny unders�gelse af papeg�jer viser, at opdelingen af hjernen
i h�jre og venstre for�ger computerkraften. L�nge har man troet, at
denne opdeling var unik for mennesker, men forskning har nu vist, at
det ogs� er udbredt hos hvirveldyr s�som papeg�jer.
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Og her st�r der s� f�lgende:
(science.com)
http://sciencenow.sciencemag.org/cgi/content/full/2009/902/4
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Divided Brains Are Smarter
By Constance Holden
ScienceNOW Daily News
2 September 2009
The two sides of the brain are responsible for different
tasks in many animals. In people, for example, the left
side is usually the language center, whereas the right side
handles more visual and spatial chores. Now, research on
parrots shows that this separation increases brainpower.
For many years, researchers thought that the division of laborin
the brain, known as cerebral lateralization, was unique to humans.
But recent research has shown that such lateralization is actually
pervasive in vertebrates. A leading theory suggests that the
attribute leads to faster, more accurate problem-solving. The theory
holds true for minnows--the ones whose brains are lateralized
are better at catching shrimp while simultaneously keeping an eye
out for predators--but many other species haven't been tested>
Among birds, parrots and crows are renowned for their cleverness.
So behavioral ecologist Culum Brown and biologist Maria Magat of
Macquarie University in Sydney, Australia, tested 40 parrots from
eight different Australian species. Just as right-handedness
indicates left-brain dominance in most humans, brain laterality was
determined in birds by observing which eye each bird used to
fixate on a piece of food and which foot grabbed it. Each bird received
a laterality score ranging from 0 (no preference) to 5 (strongly lateralized).
The parrots were then given two tests. One involved picking out
seeds from a background of similar-looking pebbles; their
performance was evaluated by dividing the number of seeds
consumed by the number of pecks. The more challenging task required birds
to obtain food hanging below their perch on a 50-centimeter-long string.
Hauling up the prize is a problem requiring a lot of beak,
foot, and eye coordination.
Today in the Proceedings of the Royal Society B, the researchers
report that birds with stronger brain asymmetries tended to be more
successful. Cockatoos tended to be the brightest and budgerigars
the dimmest, but within species there was variability according to
the degree of laterality. In the string test, for example, five strongly
lateralized birds (one right-footed and the rest
left-footed) from four species succeeded on the first try. Birds with
no lateralization performed the worst--in the pebble test they
scored 55% compared to 95% in the strongly lateralized individuals.
"These individuals have problems with coordination," says Brown.
"They try a mixture of approaches, and sometimes they manage to
muddle through it."
The authors say the experiments show that cerebral lateralization
promotes fast and accurate thinking and coordinated movements--and
hence would increase the birds' fitness, or ability to survive and reproduce.
Cognitive neuroscientist Giorgio Vallortigara of the University of Trento
in Italy, who has studied performance of chicks on the
seed-pecking test, says, "The idea of a link between lateralization
strength and cognitive abilities has been around ... for many
years, but little comparative and experimental work has been done
with animals." This study, he says, provides "fascinating
confirmation of the link between higher cognition and brain asymmetry."
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Og p� dansk st�r der s�ledes ...
(NB! �redigeret overs�ttelse via http://translate.google.dk/translate_t# )
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Delt hjerner er mere intelligente
Ved Constance Holden
ScienceNOW Daily News
2 September 2009
De to sider af hjernen er ansvarlige for forskellige
opgaver i mange dyr. I mennesker, for eksempel, venstre
side er normalt sprog centrum, mens h�jre side
h�ndterer mere visuel og rumlig g�rem�l. Nu, forskning
papeg�jer viser, at denne adskillelse �ger intellektuelle ressourcer.
I mange �r troede forskerne, at opdelingen af laborin
hjernen, kaldet cerebral lateralization, var enest�ende for mennesker.
Men nyere forskning har vist, at en s�dan lateralization er faktisk
omsiggribende hos hvirveldyr. En f�rende teori foresl�r, at
attribut f�rer til hurtigere og mere pr�cis probleml�sning. Teorien
g�lder for minnows - dem, hvis hjerne er lateralized
er bedre til at fange rejer og samtidig holde �je
ud for rovdyr - men mange andre arter er ikke blevet testet>
Blandt fugle, er papeg�jer og krager kendt for deres dygtighed.
S� adf�rdsm�ssige �kolog Culum Brown og biolog Maria Magat af
Macquarie University i Sydney, Australien, testet 40 papeg�jer fra
otte forskellige australske arter. Ligesom h�jre-h�ndethed
angiver venstre-hjerne dominans i de fleste mennesker, hjerne laterality var
bestemmes i fugle ved at iagttage, som �jet hver fugl, der anvendes til at
fiksere p� et stykke af f�devarer, og som fod greb den. Hver fugl, fik
en laterality score p� mellem 0 (ingen pr�ference) til 5 (st�rkt lateralized).
Papeg�jerne blev derefter givet to tests. Var involveret piller ud
fr� fra en baggrund af lignende udseende sm�sten; deres
resultater blev evalueret ved at dividere antallet af fr�
forbruges af antallet af hel T�nde. Jo mere udfordrende opgave kr�vede fugle
at f� mad h�ngende under deres aborre p� en 50 centimeter lang streng.
Indhaling pr�miepengene er et problem, der kr�ver en masse n�b,
fods, og �je koordination.
Dag i Proceedings of the Royal Society B, forskerne
rapport, at fugle med st�rkere hjernen asymmetrier tendens til at v�re mere
vellykket. Kakaduer tendens til at v�re de klogeste og undulater
Det dimmest, men inden for arter, der var variation i henhold til
graden af laterality. I strengen test, for eksempel fem st�rkt
lateralized fugle (en h�jre ben og resten
venstre-footed) fra fire arter lykkedes i f�rste fors�g. Fugle med
ingen lateralization udf�rt de v�rste - i pebble test de
scorede 55% i forhold til 95% i den st�rkt lateralized enkeltpersoner.
"Disse personer har problemer med koordinering," siger Brown.
"De fors�ger en blanding af strategier, og nogle gange det lykkes dem at
klarer sig igennem det. "
Forfatterne siger, at eksperimenter viser, at cerebral lateralization
fremmer hurtig og pr�cis t�nkning og koordinerede bev�gelser - og
derfor ville �ge fuglenes kondition, eller evne til at overleve og formere sig.
Kognitiv neurolog Giorgio Vallortigara fra universitetet i Trento
i Italien, som har studeret udf�relsen af kyllinger p�
fr�-hakke test, siger: "Tanken om en sammenh�ng mellem lateralization
styrke og kognitive evner har v�ret omkring ... for mange
�r, men har lidt sammenlignende og eksperimentelt arbejde er gjort
med dyr. "Denne unders�gelse, siger han, giver" fascinerende
bekr�ftelse af forbindelsen mellem h�jere kognition og hjerne asymmetri. "
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�h ...
Jeg "fristes" over evne til at komme ind p� det vi i psykologiens verden kalder
spejlning; fordi ...
Det er en kendsgerning, at de to hjernehalvdele er i stand til *selvst�ndigt* at
drage konklusioner (uanh�ngigt af hinanden).
(Og den fristende tanke best�r s� i, at ...)
Og ved at spejle sig i hinanden, opn�s der derved en art selvbevidsthed (med
dertil h�rende veto-ret und so weiter) ?
With kind regards,
Mogens Kall, The servant of Michael, the *fool* of Christ.
--
Coming up news: Iran hit by a Asteroid. Iran is no more (Jer.49,34-)
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http://sites.google.com/site/theservantofmichaelshomepage File no: 9632
Martin Larsen
news:4a9fbd64$0$283$1472...@news.sunsite.dk...
Der kan vist s� ikke l�ngere v�re nogen der kan s� berettiget tvivl om denne
sidespecialisering?
Mvh
Martin