Natural selection and cultural rates of change
It has been claimed that a meaningful theory of cultural evolution is not possible because human beliefs and behaviors do not follow predictable patterns. However, theoretical models of cultural transmission and observations of the development of societies suggest that patterns in cultural evolution do occur. Here, we analyze whether two sets of related cultural traits, one tested against the environment and the other not, evolve at different rates in the same populations. Using functional and symbolic design features for Polynesian canoes, we show that natural selection apparently slows the evolution of functional structures, whereas symbolic designs differentiate more rapidly. This finding indicates that cultural change, like genetic evolution, can follow theoretically derived patterns.
The name of the supercomputer is literal: Each of its microchips has been programmed to act just like a real neuron in a real brain. The behavior of the computer replicates, with shocking precision, the cellular events unfolding inside a mind.
Smallpox or Facebook?
Which better explains how ideas move through society: diseases or social networks?
Paradoxical Alzheimer's Finding May Shed New Light On Memory Loss
| Who'd a thunk? Younger brains show evidence of more memory loss than those with Alzheimer's. But those younger brains are also making memories faster than they lose them. A new study shows that normal memory loss is hyperactivated in Alzheimer's, pointing to AD as a syndrome affecting the plasticity or malleability of the brain.
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| It's common knowledge that humans and other animals are able to visually judge depth because we have two eyes and the brain compares the images from each. But we can also judge depth with only one eye, and scientists have been searching for how the brain accomplishes that feat.
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| For the first time, a researchers have linked pain receptors found throughout the nervous system to learning and memory in the brain. The findings, published in Neuron, point up new drug targets for memory loss or epileptic seizures.
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| A new study of whether people receive different quality of hospital care because of their race or ethnicity found that when whites and minorities are admitted to a hospital for the same reason, they receive the same quality care in that hospital.
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| Researchers have discovered that a system in the brain for processing grammar is impaired in some children with specific language impairment, but that these children compensate with a different brain area. The findings offer new hope for sufferers of with specific language impairment, which affects seven percent of children and is a major cause of many not reaching their educational potential.
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| Researchers have made an important neurobiological discovery of how humans learn to predict risk. The research, appearing in the Journal of Neuroscience, will shed light on why certain kinds of risk, notably financial risk, are often underestimated, and whether abnormal behavior such as addiction (e.g. to gambling or drugs) could be caused by an erroneous evaluation of risk.
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| A new CDC study estimates that one in four (26 percent) young women between the ages of 14 and 19 in the United States -- or 3.2 million teenage girls -- is infected with at least one of the most common sexually transmitted diseases.
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| Scientists are developing systems that process and understand spoken language and automatically obtain information particularly from Basque radio and television. Carrying out a search in the net for written documents is an easy task – the word is simply introduced in to the search tool. Nevertheless, these searches do not work with the spoken word or with audio archives, unless these have an accompanying written explanation.
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| While life expectancy has increased significantly for educated people over the last twenty years, it has plateaued for less educated people. In other words, those whose education level does not exceed high school have not been sharing the benefits of prolonged lifespan. This is the case for both African Americans and Caucasians. Deaths related to tobacco use account for at least one-fifth of the growth in mortality differences by education that create this life expectancy gap.
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| Leading academic research institutions seek increased NIH funding to reverse effects that are threatening advances in medicine. They warned that if NIH does not get consistent and robust support in the future, the nation will lose a generation of young investigators to other careers and other countries and, with them, a generation of promising research that could cure disease for millions for whom no cure currently exists.
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| Parental monitoring can reduce high-school drinking and, as a result, have a protective effect on students' drinking at college. Underage drinking is linked to a number of negative outcomes in this group, including suicide, high-risk sexual activity and an increased chance of alcohol dependence.
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| Scientists are engineering video game characters with the capacity to have beliefs and to reason about the beliefs of others. The characters will be able to predict and manipulate the behavior of even human players, with whom they will directly interact in the real, physical world, according to the team.
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