7,058 research outputs found
An evolved cognitive bias for social norms
Social norms are a widely used concept for explaining human behavior, but there are few studies exploring how we cognitively utilize them. We incorporate here an evolutionary approach to studying social norms, predicting that if norms have been critical to biological fitness, then individuals should have adaptive mechanisms to conform to, and avoid violating, norms. A cognitive bias toward norms is one specific means by which individuals could achieve this. To test this, we assessed whether individuals have greater recall for normative information than for nonnormative information. Three experiments were performed in which participants read a text and were then tested on their recall of behavioral content. The data suggest that individuals have superior recall for normative social information and that performance is not related to rated importance. We discuss how such a cognitive bias may ontogenetically develop and identify possible hypotheses that distinguish between alternative explanatory accounts for social norms
Mammals of Southwestern Arkansas Part II. Rodents
This study investigated the composition and habitat affinities of the mammalian fauna of southwestern Arkansas. The study area was comprised of the 21 counties located south and/or west of and including Pulaski County. The previously existing data set pertaining to the mammals of Arkansas was notably incomplete and this study area in particular, was poorly known mammalogically. Specimens were collected by standard trapping and salvage methods throughout the study area. The mammals considered during this study were limited to those species meeting a set of criteria designed to eliminate species that had been introduced or artificially maintained. This study has accumulated records of 25 species of rodents; over 1500 specimens have been recorded; and a total of 95 new county records have been documented
Accessing Rydberg-dressed interactions using many-body Ramsey dynamics
We demonstrate that Ramsey spectroscopy can be used to observe
Rydberg-dressed interactions. In contrast to many prior proposals, our scheme
operates comfortably within experimentally measured lifetimes, and accesses a
regime where quantum superpositions are crucial. The key idea is to build a
spin-1/2 from one level that is Rydberg-dressed and another that is not. These
levels may be hyperfine or long-lived electronic states. An Ising spin model
governs the Ramsey dynamics, for which we derive an exact solution. Due to the
structure of Rydberg interactions, the dynamics differs significantly from that
in other spin systems. As one example, spin echo can increase the rate at which
coherence decays. The results also apply to bare (undressed) Rydberg states as
a special case, for which we quantitatively reproduce recent ultrafast
experiments without fitting
Finite-size scaling at infinite-order phase transitions
For systems with infinite-order phase transitions, in which an order
parameter smoothly becomes nonzero, a new observable for finite-size scaling
analysis is suggested. By construction this new observable has the favourable
property of diverging at the critical point. Focussing on the example of the
F-model we compare the analysis of this observable with that of another
observable, which is also derived from the order parameter but does not
diverge, as well as that of the associated susceptibility. We discuss the
difficulties that arise in the finite-size scaling analysis of such systems. In
particular we show that one may reach incorrect conclusions from large-system
size extrapolations of observables that are not known to diverge at the
critical point. Our work suggests that one should base finite-size scaling
analyses for infinite-order phase transitions only on observables that are
guaranteed to diverge.Comment: 7 pages, 5 figures, 1 table; v2: publication details adde
Ultracold nonreactive molecules in an optical lattice: connecting chemistry to many-body physics
We derive effective lattice models for ultracold bosonic or fermionic
nonreactive molecules (NRMs) in an optical lattice, analogous to the Hubbard
model that describes ultracold atoms in a lattice. In stark contrast to the
Hubbard model, which is commonly assumed to accurately describe NRMs, we find
that the single on-site interaction parameter is replaced by a
multi-channel interaction, whose properties we elucidate. The complex,
multi-channel collisional physics is unrelated to dipolar interactions, and so
occurs even in the absence of an electric field or for homonuclear molecules.
We find a crossover between coherent few-channel models and fully incoherent
single-channel models as the lattice depth is increased. We show that the
effective model parameters can be determined in lattice modulation experiments,
which consequently measure molecular collision dynamics with a vastly sharper
energy resolution than experiments in an ultracold gas.Comment: 4 pages+refs, 3 figures; 2.5 pages+1 figure Supplemental Materia
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