Oct
28
2008
0

Trends in Marital Fidelity

http://www.nytimes.com/2008/10/28/health/28well.html?8dpc

Two excerpts:

Theories vary about why more people appear to be cheating. Among older people, a host of newer drugs and treatments are making it easier to be sexual, and in some cases unfaithful — Viagra and other remedies for erectile dysfunction, estrogen and testosterone supplements to maintain women’s sex drive and vaginal health, even advances like better hip replacements.

“They’ve got the physical health to express their sexuality into old age,” said Helen E. Fisher, research professor of anthropology at Rutgers and the author of several books on the biological and evolutionary basis of love and sex…

The General Social Survey data also show some encouraging trends, said John P. Robinson, professor of sociology and director of the Americans’ Use of Time project at the University of Maryland. One notable shift is that couples appear to be spending slightly more time together. And married men and women also appear to have the most active sex lives, reporting sex with their spouse 58 times a year, a little more than once a week.

“We’ve looked at that as good news,” Dr. Robinson said.

Written by Elliott in: Uncategorized |
Oct
25
2008
1
Oct
23
2008
1

Humans reflexively synchronize to rhythms

Nice article on human auditory capabilities and music perception by Trehub and Hannon (2006):

Here’s the abstract:

We review the literature on infants’ perception of pitch and temporal patterns, relating it to comparable research with human adult and non-human listeners. Although there are parallels in relative pitch processing across age and species, there are notable differences. Infants accomplish such tasks with ease, but non-human listeners require extensive training to achieve very modest levels of performance. In general, human listeners process auditory sequences in a holistic manner, and non-human listeners focus on absolute aspects of individual tones. Temporal grouping processes and categorization on the basis of rhythm are evident in non-human listeners and in human infants and adults. Although synchronization to sound patterns is thought to be uniquely human, tapping to music, synchronous firefly flashing, and other cyclic behaviors can be described by similar mathematical principles. We conclude that infants’ music perception skills are a product of general perceptual mechanisms that are neither music nor species-specific. Along with general-purpose mechanisms for the perceptual foundations of music, we suggest unique motivational mechanisms that can account for the perpetuation of musical behavior in all human societies.

And some excerpts:

Adults are biased to group successive events according to their similarity in spectral structure (timbre), pitch, intensity, temporal proximity, or spatial location. For example, they segment a repeating, ambiguous pattern into groups of similar elements, reporting XXXOO or OOXXX, which begin and end with multiple instances of the same element (X or O) but rarely reporting OXXOO, which cuts across multiple identical elements (O) (Royer & Garner, 1966)…

French newborns distinguish speech samples from different rhythmic classes, such as English and Japanese, but not those within the same rhythmic class, such as English and Dutch (Nazzi, Bertoncini, & Mehler, 1998)…

Measures of durational contrast in English and French are associated with culture- specific rhythms in music from England and France, which implies that rhythmic structures in speech influence, or are influenced by, rhythmic structures in music (Patel & Daniele, 2003)…

[P]igeons categorize temporal intervals on the basis of relative duration (longer or shorter) (Zentall, Weaver, & Clement, 2004), and starlings (Hulse, Humpal, & Cynx, 1984a) as well as bottle-nosed dolphins (Harley et al., 2003) discriminate contrasting rhythms composed of identical intervals. After starlings learn to respond differentially to rhythmic versus arrhythmic patterns, they show generalization to patterns with altered tempo and tone frequency (Hulse, Humpal, & Cynx, 1984b). Dolphins also discriminate rhythms despite transformations of pitch level and tempo (Harley et al., 2003). These findings imply that rhythmic patterns are salient for non-human as well as human listeners…

When adults are asked to tap to music, they show a high degree of inter-subject agreement, tapping at metrically strong beats in the music (Drake, Penel, & Bigand, 2000; Snyder & Krumhansl, 2001)… [T]he tendency to perceive meter is so strong that most listeners perceive a ‘‘tick-tock’’ or strong–weak pattern in isochronous patterns of uniform tones (Brochard, Abecasis, Potter, Ragot, & Drake, 2003)…

Synchronized movement to music has been observed in all known cultures, which implies that this skill is universal and perhaps unique to human musical behavior (Brown, 2003)… There are no known examples of non-human animals synchronizing their behavior to music, which makes it tempting to suggest that musical meter is species-specific. The closest non-human parallel to musical meter is the synchronous flashing of fireflies. Some firefly species synchronize their flashing with that of other fireflies and with flashing artificial lights, typically in the context of courtship (Buck, 1988). Interestingly, some species synchronize at multiples of an exogenous stimulus, an ability that is characteristic of human responses to musical meter (Buck, 1988). Different mechanisms may underlie firefly flashing and human dancing, but similar mathematical principles can describe and predict synchronization in firefly flashing, human tapping, sleep–wake cycles, menstrual cycles, and many other processes, which implies that synchronization is common or even inevitable (Glass, 2001; Large & Kolen, 1994; Strogatz, 2003). Perhaps human listeners’ perception of meter arises from a simple, widespread mechanism of synchronization rather than from unique, music-specific abilities.

Written by Elliott in: Uncategorized |
Oct
23
2008
2

Towards a unified science of cultural evolution

A group of heterodox cultural anthropologists have begun examining human cultural change through the lens of Darwinian evolution. Alex Mesoudi and colleagues offer this encouraging preliminary assessment of the field:

http://journals.cambridge.org/action/displayFulltext?type=6&fid=544784&jid=&volumeId=&issueId=04&aid=544776&fulltextType=RA&fileId=S0140525X06009083

Some excerpts:

Cultural traits go extinct as a result of competition, as occurred with the gun in Japan (Perrin 1979) and with bone tools in Tasmania (Diamond 1978). Basalla (1988) amassed extensive historical evidence for the gradual accumulation of modifications through time, such as Joseph Henry’s 1831 electric motor, which borrowed many features from the steam engine, or Eli Whitney’s 1793 cotton gin, which was based on a long line of Indian devices…

Culture exhibits the convergent evolution of similar forms in unrelated lineages, such as the tendency for both teddy bears (Hinde & Barden 1985) and cartoon characters (Gould 1980) to become increasingly neotenous over the course of time. Finally, cultural traits change in function or become vestigial, as documented by Basalla (1988) for numerous technological artifacts, such as the no longer optimal QWERTY keyboard layout…

Other evolutionary archaeologists have adapted neutral drift models from evolutionary biology (e.g., Crow & Kimura 1970) to account for “stylistic variation” in artifacts. For example, Neiman (1995) demonstrated that changes in decorative styles of Illinois Woodland ceramics can be predicted by a model incorporating the selectively neutral but opposing forces of drift and innovation…

Howe et al. (2001) describe how different manuscript versions of the same text can be used to reconstruct the evolution of that text. This was demonstrated by Barbrook et al. (1998), who used cladistic methods to reconstruct the historical relationships between 58 different manuscripts of Chaucer’s Canterbury Tales, improving on previous non-phylogenetic reconstructions. Bentley et al. (2004), meanwhile, found that the frequencies of first names and patent applications in twentieth-century United States both conform to a simple model of random copying originally developed in evolutionary biology

For example, McKone and Halpern (2003) developed a population genetic model of androgenesis, a rare phenomenon seen in freshwater clams, Saharan cypress trees, and stick insects, where the offspring acquire nuclear DNA from the male parent only. The model predicts that mutations causing androgenesis will often spread rapidly to fixation in an initially non-androgenetic population, and in some cases cause extinction of that population because of the loss of females, perhaps explaining the rarity of such mutations.

Feldman and Cavalli-Sforza (1989) modelled the coevolution of genes for lactose absorption and the cultural trait of dairy farming, finding that the allele for lactose absorption will spread provided there is a high probability that the offspring of dairy farmers themselves become dairy farmers, but not otherwise, even with a significant viability advantage. Another case study examined the evolution of handedness (Laland et al. 1995b), proposing a model that gave a better fit to patterns of handedness in families and among twins than do leading purely genetic models…

Boyd and Richerson (1985), meanwhile, have developed a model of runaway cultural selection similar to runaway sexual selection, which they argue can account for a range of cultural traits, from oversized yams in Ponapae to extensive tattooing in Polynesia (paralleling elaborate sexually selected biological traits such as the peacock’s tail)…

…research in sociology on the diffusion of innovations (Rogers 1995) examines how new ideas and technologies are transmitted through naturally occurring populations. Typically, questionnaires or interviews are employed to assess the past and present use of the innovation by the respondent, and used to compile a picture of diffusion through the population. Classic studies have examined the diffusion of new types of seed among farmers (Ryan & Gross 1943) and antibiotic among doctors (Coleman et al. 1966). A recurring finding from more than 3,000 diffusion studies is an S-shaped cumulative adoption curve (Rogers 1995), which indicates a slow initial uptake, followed by a rapid increase in adoption, and finally another slow period as the population reaches saturation (similar sigmoidal dynamics characterise the diffusion of alleles)…

Many of these diffusion studies, however, can be criticised for not clearly identifying a priori the putative selection pressure responsible for the diffusion and then testing this prediction in natural populations, as is commonly done in evolutionary biology (Endler’s first method)… One recent study that did specify a priori a hypothesised selection pressure is Bangerter and Heath’s (2004) study of the “Mozart effect,” the idea that exposure to classical music enhances intelligence, especially during childhood. Although it has very weak scientific support, this idea has gained wide currency in the United States mass media, which Bangerter and Heath (2004) hypothesised was because it offers a cheap and easy way of supposedly enhancing one’s child’s development. This hypothesis predicts that the Mozart effect should be more prevalent in the mass media of states where there is poor academic performance and low spending on education, which Bangerter and Heath showed to be the case…

[C]ultural traits may adapt to physical features of the environment such as temperature or rainfall. Cultural traits may also compete with and adapt to other cultural knowledge, equivalent to the biotic environment. Finally, cultural traits may adapt to biologically evolved or implicit features of human cognition. This has no exact equivalent in the biological world, although perhaps there is a loose parallel in genetic or developmental constraints on adaptation, or in the coevolution of symbionts and hosts (Dennett 2001; 2002)…

The practical methods of human behavioural ecology… involve observing and recording behaviour in natural environments… guided by the predictions of formal mathematical models… An example is the occurrence in Tibet of polyandry, which has been shown to be functionally adaptive under the particularly harsh environmental conditions of the region (Crook & Crook 1988)…

[B]ecause cultural traits rely predominantly on human minds for their storage and transmission, there is the possibility of adaptation to biologically evolved or developmentally acquired cognitive features of those minds… Evolutionary psychology (e.g., Barkow et al. 1992) also provides a rich theoretical and empirical body of research on biologically evolved features of human cognition that might be predicted to bias cultural transmission in particular directions. Sperber and Hirschfeld (2004) similarly argue that the diversity of some cultural traits, such as religious beliefs or classifications of animals and plants, is the result of adaptation to biologically evolved domain-specific cognitive capacities (e.g., folk biology; Atran 1998). There is also evidence that biomechanical properties of the human vocal apparatus significantly constrain the form of words (MacNeilage & Davis 2000). The infant vocal tract, for example, favours simple consonant-vowel alternations such as “dada” and “mama” (MacNeilage & Davis 2000), which may explain why such word forms are used in many languages to denote parents…

It may also be fruitful to study the adaptation of cultural traits to alternative transmission media such as printed documents or the Internet, and to examine whether such media are merely direct extensions of cognitive capacities or whether they generate their own novel transmission constraints (see Donald 1991)…

In order to illustrate the universality and substrate-neutrality of his replicator-centred theory of evolution, Dawkins (1976) coined the term meme to describe a cultural replicator, or a unit of cultural transmission. Memetics has been developed further by Hull (1982), Dennett (1995), Blackmore (1999), and Aunger (2000b; 2002), amongst others…

A more detailed picture of the mechanisms of cultural transmission requires an understanding of how the brain processes relevant information…

Aunger (2002) has recently attempted to integrate memetics with neuroscience, arguing that a robust conceptualisation of the “meme” must specify its material basis in the brain. He proposes that memes should be seen as electrochemical states of multiple neurons, and offers a definition of a “neuromeme” as “a configuration in one node of a neuronal network that is able to induce the replication of its state in other nodes” (p. 197). As Aunger acknowledges, however, any attempt to provide a more detailed description and theory of a neuromeme is severely limited by the current lack of understanding within neuroscience concerning the precise neural and molecular basis of how learned information is stored in the brain…

[T]here are several reports of category-specific naming impairments of human patients with brain damage who have been found to recognise and correctly name all items except those in a specific category, such as fruits and vegetables or country names (Crosson et al. 1997). Such studies suggest that at least some learned knowledge stored in human brains is organised into separable semantic categories. There is also recent evidence that single neurons in the human medial temporal lobe respond to the higher-order abstract representation of a specific person or building (Quiroga et al. 2005)…

[T]here is evidence from a number of species of behavioural traditions not obviously attributable to genetic or ecological differences, and hence thought to constitute socially learned cultural patterns. For example, Whiten et al. (1999; 2001) documented 39 putative cultural traits in chimpanzees from various regions of Africa, such as tool usage and grooming behaviour. Similar regional differences inferred to be cultural in origin have been observed in orangutans (van Schaik et al. 2003) and capuchins (Fragaszy & Perry 2003; Perry et al. 2003a), as well as in the vocalisations of birds (Catchpole & Slater 1995) and mammals (especially cetaceans: Janik & Slater 1997), and behavioural traditions in fish (Helfman & Schultz 1984; Warner 1990). There are obvious parallels here with the databases compiled by cultural anthropologists documenting worldwide geographical variation in human culture…

[A] number of studies have tracked the diffusion of innovations within nonhuman communities, paralleling the research tradition of the same name for human technology (Rogers 1995). The most famous case is the diffusion of potato-washing in a community of Japanese macaques (Kawai 1965). Lefebvre (1995) found that 16 of 21 reported cases of the diffusion of foraging innovations in primates exhibit a rapid accelerating pattern of adoption characteristic of cultural transmission (an example of which is the S-shaped distribution reported by Rogers 1995)…

[P]opulation genetic modelling has been used to analyse patterns of nonhuman culture, specifically birdsong. Lynch and Baker (1993) found that the geographical distribution of chaffinch songs can be accounted for by a neutral model in which mutation, migration, and drift are at equilibrium. Lachlan and Slater (1999) adopted gene-culture coevolution methods to find that vocal learning can be maintained in a “cultural trap” formed by the interaction between genes (which specify the constraints on songs) and culture (the songs themselves). Gene-culture coevolutionary methods have also been used to explore how song learning might affect speciation (Beltman et al. 2004) and the evolution of brood parasitism (Beltman et al. 2003).

Written by Elliott in: Uncategorized |
Oct
22
2008
1

Jojo and Mikey suffer alternative perspective

The Bryan/College Station Eagle endorses Barack Obama for president:

http://www.theeagle.com/editorial/Barack-Obama-is-the-better-choice-for-president

This is the first time in 50 years that the conservative paper has endorsed a Democrat for president.

Jojo and Mikey, by the way, are my cousins attending college in College Station. In fact, every one of the four college-age cousins in my family are attending college there.

Written by Elliott in: Uncategorized |
Oct
22
2008
0

Fetal Hormones Influence Personality

Olivia Judson has a great essay in the New York Times about the effect of hormones on personality:

…the early environment matters. In rats, mice, gerbils and ferrets — all of which have several offspring in each litter — a pup’s position in the uterus will have a lasting effect on its personality. A female mouse who was between two females will be more docile than a female who was between two males. She will also be more attractive to males. Similarly, a male mouse who finds himself between two females will have a higher sex drive than a male who was between two other males. He will also be less likely to help look after the pups, and he’ll have a stronger preference for sweet food. Here again, the reason is hormones. Developing fetuses give them off, so the neighborhood an embryo finds itself in affects which hormones it gets exposed to while it is growing…

As adults, rats and mice whose mothers were stressed during pregnancy tend to be more timid and anxious than other animals: they tend to be more reluctant to explore new environments, or to come out of their cages when the door has been left open. A mother’s stress can also make it harder for her pups to learn their way through mazes…

…evidence is mounting that humans are affected in much the same way that other animals are. Exposure to estrogen and testosterone affects behavior in adults. And children whose mothers were stressed during pregnancy often have learning problems, and may be more prone to anxiety.

I suppose that, like the mice, Ryan and I exuded hormones that influenced each others’ personalities.

Written by Elliott in: Uncategorized |
Oct
21
2008
0

Evil Delusions

Little did the Hutu know, but the ethnic division between Hutu and Tutsi was artificially arbitrated by their Belgian colonial conquerors:

http://en.wikipedia.org/wiki/Hutu_Ten_Commandments

Written by Elliott in: Uncategorized |
Oct
21
2008
0

Owners of ScienceDirect Engaged in Arms Trade

From the Wikipedia article for science publisher Elsevier:

An editorial in the medical journal The Lancet in September 2005 sharply criticized the journal’s owner and publisher, Reed Elsevier, for its participation in the international arms trade. Defence Systems and Equipment International Exhibition (DSEi), a large arms fair in the U.K. The authors, appealing to the Hippocratic oath called for the publisher to divest itself of all business interests that threaten human, and especially civilian, health and well-being.

Elsewhere in the article, it is noted that

the subscription rates charged by the company for its journals have been criticised; some very large journals (those with more than 5000 articles) charge subscription prices as high as $14,000, far above average. The company has been criticised not just by advocates of a switch to the so-called open-access publication model, but also by universities whose library budgets make it difficult for them to afford current journal prices. For example, a resolution by Stanford University’s senate singled out Elsevier as an example of a publisher of journals which might be “disproportionately expensive compared to their educational and research value” and which librarians should consider dropping, and encouraged its faculty “not to contribute articles or editorial or review efforts to publishers and journals that engage in exploitive or exorbitant pricing”. Similar guidelines and criticism of Elsevier’s pricing policies have been passed by the University of California, Harvard University and Duke University.

Written by Elliott in: Uncategorized |
Oct
20
2008
0

Limits of Human Rationality

From Gintis 2006:

Numerous experiments document that many people
have beliefs concerning probabilistic events that are
without scientific foundation, and which will likely lead
them to sustain losses if acted upon. For example, virtually
every enthusiast believes that athletes in competitive
sports run “hot and cold,” although this has never been
substantiated empirically. In basketball, when a player
has a “hot hand,” he is preferentially allowed to shoot
again, and when he has a “cold hand,” he is often taken
out of the game. I have yet to meet a basketball fan who
does not believe in this phenomenon. Yet Gilovich et al.
(1985) have shown, on the basis of a statistical analysis
using professional basketball data, that the “hot/cold
hand” does not exist.12 This is but one instance of the
general rule that our brains often lead us to perceive a
pattern when faced with purely random data. In the
same vein, I have talked to professional stock traders
who believe, on the basis of direct observation of stock
volatility, that stocks follow certain laws of inertia and elasticity
that cannot be found through a statistical analysis of
the data. Another example of this type is the “gambler’s
fallacy,” which is that in a fair game, the appearance of
one outcome several times in a row renders that
outcome less likely in the next several plays of the game.
Those who believe this cannot be dissuaded by scientific
evidence.

Written by Elliott in: Uncategorized |
Oct
20
2008
0

Blood Drinkers Slide Show

The New York Times’s science section has a couple of engaging articles about blood up today, the highlight of which is a nice slide show featuring blood-drinking animals:

http://www.nytimes.com/slideshow/2008/10/20/science/102108-Blood_index.html?partner=permalink&exprod=permalink

Written by Elliott in: Uncategorized |

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