On the functional origins of essentialism

This essay examines the proposal that psychological essentialism results from a history of natural selection acting on human representation and inference systems. It has been argued that the features that distinguish essentialist representational systems are especially well suited for representing natural kinds. If the evolved function of essentialism is to exploit the rich inductive potential of such kinds, then it must be subserved by cognitive mechanisms that carry out at least three distinct functions: identifying these kinds in the environment, constructing essentialized representations of them, and constraining inductive inferences about kinds. Moreover, there are different kinds of kinds, ranging from nonliving substances to biological taxa to within-species kinds such as sex, and the causal processes that render these categories coherent for the purposes of inductive generalization vary. If the evolved function of essentialism is to support inductive generalization under ignorance of true causes, and if kinds of kinds vary in the implicit assumptions that support valid inductive inferences about them, then we expect different, functionally incompatible modes of essentialist thinking for different kinds. In particular, there should be differences in how biological and nonbiological substances, biological taxa, and biological and social role kinds are essentialized. The functional differences between these kinds of essentialism are discussed

Understanding death as the cessation of intentional action: A cross-cultural developmental study

Determining whether or not an entity is capable of acting intentionally is a fundamental cognitive skill that emerges in the first year of infancy, and the inability to act is a key aspect distinguishing dead from living things. Though young children’s understanding of death is generally thought to be poor, an understanding of death as the permanent cessation of agency might develop early in childhood. This study tested the cessation-of-agency hypothesis cross-culturally, by examining the differences between children’s judgments about sleeping and dead animals. The results showed that children understand that death entails the permanent cessation of the ability to act by age 4 in two different cultures. This is consistent with a view that those distinctions that are most crucial for adaptive decision-making are the ones that develop earliest

Climate Change Adaptation and the Back of the Invisible Hand

We make the case that scientifically accurate and politically feasible responses to the climate crisis require a complex understanding of human cultural practices of niche construction that moves beyond the adaptive significance of culture. We develop this thesis in two related ways. First, we argue that cumulative cultural practices of niche construction can generate stable equilibria and runaway selection processes that result in long-term existential risks within and across cultural groups. We dub this the back of the invisible hand. Second, we argue that the ability of cultural groups to innovate technological solutions to environmental problems is highly constrained in ways that are exacerbated by sustained intergroup conflict, inequality and by inherently unpredictable cascades in climate change and human migration patterns. After developing these theoretical points about human cultural practices of niche construction in detail, we conclude our discussion with some tentative practical suggestions about the way that cultural evolutionary history can more fruitfully be used in efforts to remit the climate crisis and contribute to sustainable practices of human climate change adaptation

Artifacts and Original Intent: A Cross-Cultural Perspective on the Design Stance

How do people decide what category an artifact belongs to? Previous studies have suggested that adults and, to some degree, children, categorize artifacts in accordance with the design stance, a categorization system which privileges the designer’s original intent in making categorization judgments. However, these studies have all been conducted in Western, technologically advanced societies, where artifacts are mass produced. In this study, we examined intuitions about artifact categorization among the Shuar, a hunter-horticulturalist society in the Amazon region of Ecuador. We used a forced-choice method similar to previous studies, but unlike these studies, our scenarios involved artifacts that would be familiar to the Shuar. We also incorporated a community condition to examine the possible effect of community consensus on how artifacts are categorized. The same scenarios were presented to university student participants in the UK. Across populations and conditions, participants tended to categorize artifacts in terms of a creator’s intent as opposed to a differing current use. This lends support to the view that the design stance may be a universal feature of human cognition. However, we conclude with some thoughts on the limitations of the present method for studying artifact concepts

A unitary correlation operator method

The short range repulsion between nucleons is treated by a unitary correlation operator which shifts the nucleons away from each other whenever their uncorrelated positions are within the replusive core. By formulating the correlation as a transformation of the relative distance between particle pairs, general analytic expressions for the correlated wave functions and correlated operators are given. The decomposition of correlated operators into irreducible n-body operators is discussed. The one- and two-body-irreducible parts are worked out explicitly and the contribution of three-body correlations is estimated to check convergence. Ground state energies of nuclei up to mass number A=48 are calculated with a spin-isospin-dependent potential and single Slater determinants as uncorrelated states. They show that the deduced energy- and mass-number-independent correlated two-body Hamiltonian reproduces all "exact" many-body calculations surprisingly well.Comment: 43 pages, several postscript figures, uses 'epsfig.cls'. Submitted to Nucl. Phys. A. More information available at http://www.gsi.de/~fm

NMR Determination of 2D Electron Spin Polarization at ν=1/2\nu=1/2

Using a `standard' NMR spin-echo technique we determined the spin polarization of two-dimensional electrons, confined to GaAs quantum wells, from the hyperfine shift of Ga nuclei in the wells. Concentrating on the temperature and magnetic field dependencies of spin polarization at Landau level filling factor $\nu =1/2$, we find that the results are described well by a simple model of non-interacting composite fermions, although some inconsistencies remain when the two-dimensional electron system is tilted in the magnetic field.Comment: 4 pages (REVTEX) AND 4 figures (PS

Thermoelectric Response of an Interacting Two-Dimensional Electron Gas in Quantizing Magnetic Field

We present a discussion of the linear thermoelectric response of an interacting electron gas in a quantizing magnetic field. Boundary currents can carry a significant fraction of the net current passing through the system. We derive general expressions for the bulk and boundary components of the number and energy currents. We show that the local current density may be described in terms of ``transport'' and ``internal magnetization'' contributions. The latter carry no net current and are not observable in standard transport experiments. We show that although Onsager relations cannot be applied to the local current, they are valid for the transport currents and hence for the currents observed in standard transport experiments. We relate three of the four thermoelectric response coefficients of a disorder-free interacting two-dimensional electron gas to equilibrium thermodynamic quantities. In particular, we show that the diffusion thermopower is proportional to the entropy per particle, and we compare this result with recent experimental observations.Comment: 18 pages, 2 postscript figures included. Revtex with epsf.tex and multicol.sty. In the revised version, the comparison with experimental observations at $\nu=1/2, 3/2$ is extended to include the possibility of corrections due to weak impurity scattering. The conclusions that we reach regarding the applicability of the composite fermion model at these filling fractions are not affecte

Moral parochialism misunderstood: a reply to Piazza and Sousa

Our paper [1] compared two competing hypotheses. The hypothesis that we label universalistic moral evaluation holds that a definitional feature of reasoning about moral rules is that, ceteris paribus, judgements of violations of rules concerning harm, rights or justice will be insensitive to spatial or temporal distance or the opinions of authority figures. The hypothesis that we label moral parochialism, consonant with a variety of theories of the evolutionary origins of morality, holds that, because moral judgements primarily serve to navigate local social arenas, remote events will not activate the mechanisms that generate negative moral evaluation to the same extent as events occurring in the here and now, whereas the consent of local authority figures will temper condemnation. Hence, moral parochialism predicts that the collective output of the faculties responsible for moral judgement will exhibit a reduction in the severity of judgement as a function of spatial or temporal distance or the opinions of local authority figures. We provided evidence from seven diverse societies, including five small-scale societies, showing that such reductions in severity judgements exist in all of the societies examined. Piazza and Sousa [2] argue that our data do not support parochialism, and instead support universalism, because (1) Only a minority of our participants reversed their initial judgement of the wrongness of an action (from wrong to not wrong or good) when it was subsequently framed as having occurred long ago or far away, or as having been sanctioned by authority figures. (2) Our use of graduated moral judgements, rather than dichotomous judgements, is inappropriate. (3) Only a minority of our participants diminished the severity of their initial judgement of the wrongness of an action when it was subsequently framed as having occurred long ago or far away, or as having been sanctioned by an important person. These objections stem from misunderstandings of moral parochialism and the evolutionary reasoning behind it

Charge-based quantum computing using single donors in semiconductors

Solid-state quantum computer architectures with qubits encoded using single atoms are now feasible given recent advances in atomic doping of semiconductors. Here we present a charge qubit consisting of two dopant atoms in a semiconductor crystal, one of which is singly ionised. Surface electrodes control the qubit and a radio-frequency single electron transistor provides fast readout. The calculated single gate times, of order 50ps or less, are much shorter than the expected decoherence time. We propose universal one- and two-qubit gate operations for this system and discuss prospects for fabrication and scale up.Comment: 5 pages, 4 figures, updated version submitted to Physical Review