10
Mar 11

Untangling The Brain

(Link)


06
Mar 11

Giant Ant Hill Excavated

(Link)


23
Feb 11

Milford Wolpoff And Razib Khan Discuss Multiregional Evolution

Milford Wolpoff and Razib Khan discuss multiregional evolution, including Neaderthal and Denisova contributions to modern humans.

(Link)


06
Feb 11

Kathryn Clancy and John Hawks talk Anthropology

Kathryn Clancy and John Hawks talk on BlogggingHeads about anthropology, genetics, blogging, and more.

(Link)


26
Jan 11

The Secret Life of Chaos

A nice video on Chaos Theory. The video comes in 6 parts. All 6 parts are below.

part 1 of 6

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part 2 of 6

http://www.youtube.com/watch?v=wHu8iaLs9i4

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part 3 of 6

http://www.youtube.com/watch?v=Oj–pxcFUjg

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part 4 of 6

http://www.youtube.com/watch?v=AMbua0BGfFE

part 5 of 6

http://www.youtube.com/watch?v=wc0IYJm5-mE

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part 6 of 6

http://www.youtube.com/watch?v=-1x-7ZLKhjw


26
Jan 11

David Buss: Conflict Between The Sexes

Evolutionary psychologist David Buss speaks at The University of Southern Mississippi, on conflict between the sexes. The video of his talk is divided into 7 parts; all 7 parts of the video are below:

part 1 or 7

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part 2 of 7

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part 3 of 7

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part 4 of 7

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part 5 of 7

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part 6 of 7

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part 7 of 7

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10
Dec 10

Women Tend To Prefer Older Guys, Men Tend To Prefer Younger Women

From ScienceDaily

Research at the University of Abertay Dundee discovered that as women become more financially independent, they want an older, more attractive male partner.

Studies have previously found that women place greater emphasis on whether a man can provide for them, while men place more importance on good looks. The new study revealed that as women earn more and become more independent, their tastes actually change.

The finding suggests that greater financial independence gives women greater confidence in choosing their partner. Instinctive preferences for material stability and security become less important, physical attractiveness becomes more important, and the age of partner women pick also increases.
[...]
[M]ore financially independent women actually preferred even older men. We think this suggests greater financial independence gives women more confidence in partner choices, and attracts them to powerful, attractive older men.”

(Emphasis mine.)


07
Aug 10

Distinct Neural Signatures Associated With Different Learning Strategies

The process of learning requires the sophisticated ability to constantly update our expectations of future rewards so we may make accurate predictions about those rewards in the face of a changing environment. Although exactly how the brain orchestrates this process remains unclear, a new study by researchers at the California Institute of Technology (Caltech) suggests that a combination of two distinct learning strategies guides our behavior.
[...]
One accepted learning strategy, called model-free learning, relies on trial-and-error comparisons between the reward we expect in a given situation and the reward we actually get. The result of this comparison is the generation of a “reward prediction error,” which corresponds to that difference. For example, a reward prediction error might correspond to the difference between the projected monetary return on a financial investment and our real earnings.

In the second mechanism, called model-based learning, the brain generates a cognitive map of the environment that describes the relationship between different situations. “Model-based learning is associated with the generation of a ‘state prediction error,’ which represents the brain’s level of surprise in a new situation given its current estimate of the environment,” says Jan Gläscher, a postdoctoral scholar at Caltech and the lead author of the study.
[...]
Eighteen participants were scanned using functional magnetic resonance imaging as they learned the task. The brain scans showed the distinctive, previously characterized neural signature of reward prediction error — generated during model-free learning — in an area in the middle of the brain called the ventral striatum. During model-based learning, however, the neural signature of a state prediction error appeared in two different areas on the surface of the brain in the cerebral cortex: the intraparietal sulcus and the lateral prefrontal cortex.

These observations suggest that two unique types of error signals are computed in the human brain, occur in different brain regions, and may represent separate computational strategies for guiding behavior. “A model-free system operates very effectively in situations that are highly automated and repetitive — for example, if I regularly take the same route home from work,” Gläscher says, “whereas a model-based system, although requiring much greater brain-processing power, is able to adapt flexibly to novel situations, such as needing to find a new route following a roadblock.”

(Link)

For those interested, the actual paper is:
"States versus Rewards: Dissociable Neural Prediction Error Signals Underlying Model-Based and Model-Free Reinforcement Learning", by Jan P. Glascher, Nathaniel Daw, Peter Dayan and John P. O’Doherty.


18
Jun 10

Eye Color Predicts and Doesn’t Predict Perceived Dominance

Razib Khan talks about eye color predicting and not predicting perceived dominance.

First, the study replicates the common finding of some differences in perceived dominance between blue vs. brown-eyed males. But, they observed that when the eye colors were digitally manipulated the dominance ranking did not change. In other words the eye colors seem to have correlated with other traits of masculinity, rather than been a causal signal. The authors offer up a model whereby socialization of blue eyed individuals for longer periods as children (because the trait is neotenous) produces less facial masculinization. But I don’t buy the idea that this couldn’t be genetically mediated by variation on the HERC2/OCA2 locus (where most blue vs. non-blue eye color variation is controlled). In particular, I believe there’s a body of literature that melanin and testosterone production pathways affect each other so that there is a positive correlation, though the exact causal connections are still to be worked out. Note that all this only applies within populations; between population complexion differences don’t necessarily predict dominance differences because the genetic variates are not controlled as they are within populations.


30
May 10

Fines Can Make “Bad” Behavior Happen More Often (Instead Of Less Often)

From an article on daycares and late fees

The fines that most child-care centres now charge – typically $1 per minute – to discourage adults from being tardy may actually promote lateness, researchers have found.

“Certain cues can switch moral behaviour on or off,” says Samuel Bowles, director of the Behavioural Sciences Program at the Santa Fe Institute in New Mexico. “Charging for things often switches off moral behaviour.”

Bowles concluded that fines can undermine a parent’s sense of ethical obligation to be on time for the teachers. And lateness becomes “just another commodity” to purchase.

Bowles’s research assigns a moral measure to the incentive principle raised in Freakonomics, which cited a groundbreaking study on daycare fines in Israel. Shortly after six centres in Haifa began charging late parents, the experiment backfired spectacularly. Parents reacted by coming even later.

If you are interested in reading the paper this is based on it is "A Fine is a Price", by Uri Gneezy and Aldo Rustichini.