I recently finished reading The Faith Instinct: How Religion Evolved and Why It Endures, a new book by Nicholas Wade, a science writer for The New York Times. Before giving it the "full treatment" I thought it behooved me to revisit some of the scientific literature which Wade relies upon to give form to his argument. One of the pillars of The Faith Instinct is group selection, and one of the scholars who Wade specifically cites is the economist Samuel Bowles. Bowles was an author on a paper I reviewed earlier this week, on the empirical assessment of the extent of heritability of wealth across generations in various societies. But in this case what is more relevant was a paper that Bowles published in Science last spring, Did Warfare Among Ancestral Hunter-Gatherers Affect the Evolution of Human Social Behaviors?:
Since Darwin, intergroup hostilities have figured prominently in explanations of the evolution of human social behavior. Yet whether ancestral humans were largely "peaceful" or "warlike" remains controversial. I ask a more precise question: If more cooperative groups were more likely to prevail in conflicts with other groups, was the level of intergroup violence sufficient to influence the evolution of human social behavior? Using a model of the evolutionary impact of between-group competition and a new data set that combines archaeological evidence on causes of death during the Late Pleistocene and early Holocene with ethnographic and historical reports on hunter-gatherer populations, I find that the estimated level of mortality in intergroup conflicts would have had substantial effects, allowing the proliferation of group-beneficial behaviors that were quite costly to the individual altruist.
The thesis presented in this paper is essential to The Faith Instinct because a central assertion in that book is that religious behavior emerged as an evolved trait in the context of intergroup competition. In short, war among hunter-gatherers. But let us set aside the relatively controversial issue of the evolution of religion, and focus on group selection among humans, and its possible role in the emergence of the trait of altruism.
David Sloan Wilson, who just recently joined ScienceBlogs, has written extensively on the topic of group selection (or, multilevel selection, though I will use the term group selection because that is what Bowles uses). It is a controversial topic in the context of evolutionary biology. The short sketch is that naive variants of group selection were in vogue until the 1960s, when a new wave of theorists tore down its theoretical basis and offered up alternative processes to explain social behavior. In more recent years David Sloan Wilson has been leading a campaign to return group selection, or more generally multilevel selection, to respectability. Others have always "kept the faith," but only begun to speak up more forcefully in its defense recently. Why only recently? In part because skeptics of selection above the level of the individual have always assented to its theoretical possibility, but diminished the likelihood of its realized probability. With the fleshing out of some empirical data which makes that probability more than speculation, the theoretical window for group selection may translate into something more substantive.
Todo mundo gosta de saborear uma boa barra de chocolate. Infelizmente, essa atitude, em geral, é acompanhada de uma boa dose de culpa. Não seria muito bom se descobríssemos que chocolate é bom para saúde, ao invés de apenas engordar? Os efeitos do chocolate sobre o sistema circulatório têm sido sugeridos por vários estudos dos quais, poucos são bem conduzidos. Recentemente, uma prestigiosa revista de coagulação e trombose (Journal of Thrombosis and Thrombolysis) publicou uma revisão dos efeitos circulatórios e antitrombogênicos do chocolate amargo (dark chocolate). É essa revisão que comentamos abaixo.Os efeitos benéficos do chocolate são provenientes de polifenóis chamados flavonóides que estão presentes em quantidades significativas no alimento com biodisponibilidade suficiente para causar o efeito farmacológico. Acredita-se que o potencial benefício do chocolate amargo ao sistema cardiovascular seja causado por um aumento da capacidade antioxidante dos flavonóides, em especial das catequinas, epicatequinas e procianidinas no sangue. Esses efeitos são divididos em metabólicos, anti-hipertensivos, moduladores da função endotelial, anti-inflamatórios e anti-trombóticos, como mostra a figura abaixo (retirada do original).Desde a primeira descrição dos efeito antioxidantes dos polifenóis do cacau contra a oxidação da LDL (o colesterol de baixa densidade cujo nível sérico é altamente associado à aterosclerose) em 1996, estudos vêm se acumulando sobre seus efeitos cardiovasculares, principalmente associados ao uso do chocolate amargo (dark chocolate). Dada a gigantesca penetração do chocolate em nossa cultura, é importante estabelecermos os efeitos de sua ingesta. Numerosos estudos, epidemiológicos e biológicos, agora dão conta de um efeito complexo, multifacetado e consistente dos polifenóis presentes no chocolate sobre o sistema cardiovascular. Esses estudos ainda necessitam ser confirmados por ensaios clínicos randomizados, controlados, com múltiplas dosagens diferentes de modo a definir qual a proporção mais vantajosa de polifenóis mono, oligo e poliméricos. E, então, o simples prazer associado ao consumo do chocolate pode também ser justificado sob uma perspectiva saudável e por seus efeitos psicológicos (funcionamento cognitivo e melhora do humor). Entretanto, como é demonstrado no artigo, o chocolate amargo tem níveis bem mais elevados de flavonóides do que o chocolate ao leite, além do que, as proteínas lácteas podem inibir a absorção dos polifenóis. Por essa razão, e por razão dietéticas, é preferível consumir chocolate amargo do que ao leite. Sempre em quantidades "civilizadas".Lippi, G., Franchini, M., Montagnana, M., Favaloro, E., Guidi, G., & Targher, G. (2008). Dark chocolate: consumption for pleasure or therapy? Journal of Thrombosis and Thrombolysis, 28 (4), 482-488 DOI: 10.1007/s11239-008-0273-3 Read the comments on this post......
Lippi, G., Franchini, M., Montagnana, M., Favaloro, E., Guidi, G., & Targher, G. (2008) Dark chocolate: consumption for pleasure or therapy?. Journal of Thrombosis and Thrombolysis, 28(4), 482-488. DOI: 10.1007/s11239-008-0273-3 Dark chocolate: consumption for pleasure or therapy?
See original: Chocolate: Pecado ou Remédio?
RT @Wildcat2030:"we have a population explosion of ideas, but not enough brains to cover them" -Dan Dennett’s... http://tumblr.com/xt83wghrrSat, 07/11/2009 - 2:33pm | by sandygautam
@sumhuts you can subscribe to rss feed of the #cognitive tribe and keep track of all the relevant conversation happening in the tribeSat, 07/11/2009 - 2:03pm | by sandygautam
I first read Barbara Ehrenreich in 1971 when she wrote The American Health Empire: Power, Profits, and Politics with her (then) husband John Ehrenreich (Health PAC, 1971). She was by then a PhD in cell biology (Rockefeller University) and anti-war activist. We traveled in the same circles and I knew her slightly at the time. Her next book, Witches, Midwives, and Nurses: A History of Women Healers (with Deirdre English) was a new reading of women in medical history. It was an influential text in the emerging women's health movement. Since then she has published many books, several making the best seller lists and throughout an astute and still influential observer. Now she has penned a brief comment on the the alleged swine flu vaccine supply problem and who's to blame. And I find myself in complete agreement with her:
We will meet Tuesday Nov 17th at 12:30pm – 1:30pm in SSC 9244. Jeremy will be presenting an article about the potential origins of motor variation:
Osborne, L., Lisberger, S., & Bialek, W. (2005). A sensory source for motor variation Nature, 437 (7057), 412-416 DOI: 10.1038/nature03961
Remember to join the mailing list if you’re interested in receiving [...]...
See original: Journal Club: A sensory source for motor variation
A real-time timeless tweet :-) RT @ScepticGeek: [If you haven't read my post yet] Timelessness vs. Real-time http://bit.ly/39qVJZSat, 07/11/2009 - 10:15am | by sandygautam
Besides being a delicacy in Japan and various other parts of the world, sea urchins have a longstanding career as a model organism in biology. The first description of these spiny, spineless creatures can be found in Aristotle’s History of Animals, dating from the 4th century BC 1. From the 1800s onward, the sea urchin [...]...
Rast, J., Smith, L., Loza-Coll, M., Hibino, T., & Litman, G. (2006) Genomic Insights into the Immune System of the Sea Urchin. Science, 314(5801), 952-956. DOI: 10.1126/science.1134301 Genomic Insights into the Immune System of the Sea Urchin
Buckley KM, Terwilliger DP, & Smith LC. (2008) Sequence variations in 185/333 messages from the purple sea urchin suggest posttranscriptional modifications to increase immune diversity. Journal of immunology (Baltimore, Md. : 1950), 181(12), 8585-94. PMID: 19050278 Sequence variations in 185/333 messages from the purple sea urchin suggest posttranscriptional modifications to increase immune diversity.
See original: Immunology for the Spineless
As I was stuffing my face today, I wondered if the Universe cared. The short answer is no. The slightly longer and more depressing answer is: my existence is more marginal than a speck of stray DNA on a grain of sand staring at vast oceans (that's literally true, oh the irony...). Clearly, there's no point to existence except amusement. So, here's some:
On average, each of us human beings from birth till death consume about (2000 per day x 365 days x 70 years) calories. That is a pretty big number (51,100,000 calories).Big, of course, is a relative term. The big calories translates to about 0.00002 milligrams of matter. In the scheme of things--compared to, say, the amount of matter Sun converts to pure energy per second--, the amout of matter we manage to process in 70 years is stupefyingly underwhelming. Sun converts about 4,000,000,000 kilograms of mass to pure energy every second compared to our biological knickers-in-knots process*. Still, we are here and we can point a resounding finger at the Sun. That's quite something, isn't it? Life is an extraordinarily strange and fragile business whichever way you look at it (the strangeness includes the looking-at-it part too). Perhaps, in a thousand years, we may climb up the energy ladder, sit alongside stars and have a proper material breakfast of a few hundred tons of hydrogen. It would be way more amusing than what we do with the less-than-nothing we consume today. Of course, we've got to survive to do that.
*The comparison is sort of fudged. Sun does atom crushing, we don't do that. Sun literally converts the mass to energy. OTOH, we do a lot of very very minute electrochemical energy extraction. The comparison aims to show the scale of energies involved, which differ by orders of magnitude. Physics savvy readers please pitch in and clarify my muddle if needed. Read the comments on this post...
RT @Palsule: RT @ShashiTharoor @adivik2000: Must Watch free Live Stream - http://ted.indiatimes.com/ @ShashiTharoor spkng at #TEDindia 11.30Sat, 07/11/2009 - 8:09am | by sandygautam
RT @AbhiSuryawanshi: http://bit.ly/TEDxPune_Intro TEDxPune - Intro n Call for Volunteer's #TEDxPune #TEDxSat, 07/11/2009 - 8:04am | by sandygautam
Jon Foley argues for the integration of industrial and organic agriculture to meet the challenge of rising demand for agriculture production in a turbulent world in Room for Debate Blog on Can Biotech Food Cure World Hunger?
… Currently, there are two paradigms of agriculture being widely promoted: local and organic systems versus globalized and industrialized [...]
Treating the complexity of neck pain...
OLEARY, S., FALLA, D., HODGES, P., JULL, G., & VICENZINO, B. (2007) Specific Therapeutic Exercise of the Neck Induces Immediate Local Hypoalgesia. The Journal of Pain, 8(11), 832-839. DOI: 10.1016/j.jpain.2007.05.014 Specific Therapeutic Exercise of the Neck Induces Immediate Local Hypoalgesia
“There are as many theories of sleep’s functions as there are sleep researchers” :The Why of Sleep http://bit.ly/3Enbe1Sat, 07/11/2009 - 4:54am | by sandygautam
sandygautam: “There are as many theories of sleep’s functions as there are sleep researchers” :The Why of Sleep http://bit.ly/3Enbe1
sandygautam: Psychiatric Tales: Last Chapter http://j.mp/1SMPXw
See original: Psychiatric Tales: Last Chapter http://j.mp/1SMPXw