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Clarke and Beck's defense of the theoretical construct “approximate number system” (ANS) is flawed in serious ways – from biological misconceptions to mathematical naïveté. The authors misunderstand behavioral/psychological technical concepts, such as numerosity and quantical cognition, which they disdain as “exotic.” Additionally, their characterization of rational numbers is blind to the essential role of symbolic reference in the emergence of number.
Social inequality is ubiquitous in contemporary human societies, and has deleterious social and ecological impacts. However, the factors that shape the emergence and maintenance of inequality remain widely debated. Here we conduct a global analysis of pathways to inequality by comparing 408 non-industrial societies in the anthropological record (described largely between 1860 and 1960) that vary in degree of inequality. We apply structural equation modelling to open-access environmental and ethnographic data and explore two alternative models varying in the links among factors proposed by prior literature, including environmental conditions, resource intensification, wealth transmission, population size and a well-documented form of inequality: social class hierarchies. We found support for a model in which the probability of social class hierarchies is associated directly with increases in population size, the propensity to use intensive agriculture and domesticated large mammals, unigeniture inheritance of real property and hereditary political succession. We suggest that influence of environmental variables on inequality is mediated by measures of resource intensification, which, in turn, may influence inequality directly or indirectly via effects on wealth transmission variables. Overall, we conclude that in our analysis a complex network of effects are associated with social class hierarchies.
The evolution of agriculture improved food security and enabled significant increases in the size and complexity of human groups. Despite these positive effects, some societies never adopted these practices, became only partially reliant on them, or even reverted to foraging after temporarily adopting them. Given the critical importance of climate and biotic interactions for modern agriculture, it seems likely that ecological conditions could have played a major role in determining the degree to which different societies adopted farming. However, this seemingly simple proposition has been surprisingly difficult to prove and is currently controversial. Here, we investigate how recent agricultural practices relate both to contemporary ecological opportunities and the suitability of local environments for the first species domesticated by humans. Leveraging a globally distributed dataset on 1,291 traditional societies, we show that after accounting for the effects of cultural transmission and more current ecological opportunities, levels of reliance on farming continue to be predicted by the opportunities local ecologies provided to the first human domesticates even after centuries of cultural evolution. Based on the details of our models, we conclude that ecology probably helped shape the geography of agriculture by biasing both human movement and the human-assisted dispersal of domesticates.
Considerable progress in explaining cultural evolutionary dynamics has been made by applying rigorous models from the natural sciences to historical and ethnographic information collected and accessed using novel digital platforms. Initial results have clarified several long-standing debates in cultural evolutionary studies, such as population origins, the role of religion in the evolution of complex societies and the factors that shape global patterns of language diversity. However, future progress requires recognition of the unique challenges posed by cultural data. To address these challenges, standards for data collection, organisation and analysis must be improved and widely adopted. Here, we describe some major challenges to progress in the construction of large comparative databases of cultural history, including recognising the critical role of theory, selecting appropriate units of analysis, data gathering and sampling strategies, winning expert buy-in, achieving reliability and reproducibility in coding, and ensuring interoperability and sustainability of the resulting databases. We conclude by proposing a set of practical guidelines to meet these challenges.
During 1990 we surveyed the southern sky using a multi-beam receiver at frequencies of 4850 and 843 MHz. The half-power beamwidths were 4 and 25 arcmin respectively. The finished surveys cover the declination range between +10 and −90 degrees declination, essentially complete in right ascension, an area of 7.30 steradians. Preliminary analysis of the 4850 MHz data indicates that we will achieve a five sigma flux density limit of about 30 mJy. We estimate that we will find between 80 000 and 90 000 new sources above this limit. This is a revised version of the paper presented at the Regional Meeting by the first four authors; the surveys now have been completed.
We welcome Norenzayan et al.’s claim that the prosocial effects of beliefs in supernatural agents extend beyond Big Gods. To date, however, supporting evidence has focused on the Abrahamic Big God, making generalisations difficult. We discuss a recent study that highlights the need for clarity about the causal path by which supernatural beliefs affect the evolution of big societies.
Tool use is widespread in the animal kingdom. It has been reported in taxa ranging from insects to primates (see reviews in Beck, 1980; Bentley-Condit & Smith, 2010; Shumaker et al., 2011). However, although it is taxonomically widespread, tool use is relatively rare. The rarity of tool use is surprising given the potential evolutionary advantages that a species can gain. Tools can be used to extract rich food sources such as termites and wood-boring larvae that would otherwise be extremely difficult to obtain. Given the obvious advantages of tool use, an equally obvious question is why tool use is seen in very few species.
A glance across the species that use objects as tools rules out any simple association between the presence or absence of tool use and level of cognitive ability. Tool use is seen in insects, marine invertebrates and fish, as well as in birds and mammals. Indeed, Jane Goodall (1970) recognized that the evolutionary processes underpinning tool use across the animal kingdom will be very different. Beck (1980) emphasized that there was no simple correlation between the presence of tool use and cognitive abilities. Hansell and Ruxton (2008) recently proposed another possible explanation for the rarity of tool use in animals – that tool use was rare simply because of the lack of ecological contexts in which it was advantageous (we call this the lack-of-utility hypothesis). However, we will show here that an “excess of opportunity” clearly contradicts the lack-of-utility hypothesis because in evolutionary terms tool use appears to be potentially much more useful than its frequency in the animal kingdom indicates. Given its potential usefulness, why is tool use so rare?
Ramsey et al. attempt to clarify methodological issues for identifying innovative behaviour. Their effort is seriously weakened by an underlying presumption that the behavior of primates is generally learned and that of non-primates is generally “innate.” This presumption is based on a poor grasp of the non-primate literature and a flawed understanding of how learned behaviour is genetically assimilated.
Adult albino mammals have specific retinal defects, including
reduced numbers of rod photoreceptors. To examine when
this rod deficit arises and whether it exists in nonmammalian
albinos, we have used absorbance spectrophotometry to measure
photopigment levels in dark-adapted eyes taken from three
groups of pigmented and albino animals: adult rodents (rats
and mice), developing rats, and mature Xenopus
frogs. Rhodopsin concentrations were consistently and significantly
reduced in mammalian albinos compared to their wild-type
counterparts from before the time of eye opening, but photopigment
levels were similar in frogs of both pigmentation phenotypes.
The results strongly suggest that deficits in the rod cell
population arise early in development of the mammalian
albino retina, but do not generalize to nonmammalian mutants
lacking retinal melanin.
Deaf children of elementary and secondary school age participated in a study designed to
examine their understanding of display rules, the principles governing the expression and
concealment of emotion in social situations. The results showed that deaf children's
knowledge of display rules, as measured by their reported concealment of emotion, was
comparable to that of hearing children of the same age. However, deaf children were less
likely to report that they would conceal happiness and anger. They were also less likely to
produce reasons for concealing emotion and a smaller proportion of their reasons were
prosocial, that is, relating to the feelings of others. The results suggest that the understanding
of display rules (which function to protect the feelings of other people) may develop more
gradually in deaf children raised in a spoken language environment than it does in hearing
Deaf children aged 4 to 16 years were given a false-belief test
of theory of mind. Although
the children experienced difficulty with the test, relative to hearing
children, confirming a
report by Peterson and Siegal (1995), performance was age-related, with
higher proportion of 13- to 16-year-olds passing the test. It was concluded
that deaf children
raised in a spoken language environment show a developmental delay in theory
acquisition. This delay is consistent with the assumption that their early
learning about mental states are relatively restricted and that the normal
theory of mind is dependent upon such opportunities.
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