How fairness and dominance guide young children’s bargaining decisions

Reaching agreements in conflicts is an important developmental challenge. Here, German 5-year- olds (N = 284, 49% female, mostly White, mixed socioeconomic backgrounds; data collection: June 2016–November 2017) faced repeated face-to- face bargaining problems in which they chose between fair and unfair reward divisions. Across three studies, children mostly settled on fair divisions. However, dominant children tended to benefit more from bargaining outcomes (in Study 1 and 2 but not Study 3) and children mostly failed to use leverage to enforce fairness. Communication analyses revealed that children giving orders to their partner had a bargaining advantage and that children provided and responded to fairness reasons. These findings indicate that fairness concerns and dominance are both key factors that shape young children's bargaining decision

Sign change of the Grueneisen parameter and magnetocaloric effect near quantum critical points

We consider the Grueneisen parameter and the magnetocaloric effect near a pressure and magnetic field controlled quantum critical point, respectively. Generically, the Grueneisen parameter (and the thermal expansion) displays a characteristic sign change close to the quantum-critical point signaling an accumulation of entropy. If the quantum critical point is the endpoint of a line of finite temperature phase transitions, T_c \propto (p_c-p)^Psi, then we obtain for p<p_c, (1) a characteristic increase \Gamma \sim T^{-1/(\nu z)} of the Grueneisen parameter Gamma for T>T_c, (2) a sign change in the Ginzburg regime of the classical transition, (3) possibly a peak at T_c, (4) a second increase Gamma \sim -T^{-1/(nu z)} below T_c for systems above the upper critical dimension and (5) a saturation of Gamma \propto 1/(p_c-p). We argue that due to the characteristic divergencies and sign changes the thermal expansion, the Grueneisen parameter and magnetocaloric effect are excellent tools to detect and identify putative quantum critical points.Comment: 10 pages, 7 figures; final version, only minor change

Why should I trust you?: Investigating young children’s spontaneous mistrust in potential deceivers

Children must learn not to trust everyone to avoid being taken advantage of. In the current study, 5- and 7-year-old children were paired with a partner whose incentives were either congruent (cooperative condition) or conflicting (competitive condition) with theirs. Children of both ages were more likely to mistrust information spontaneously provided by the competitive than the cooperative partner, showing a capacity for detecting contextual effects on incentives. However, a high proportion of children, even at age 7, initially trusted the competitive partner. After being misled once, almost all children mistrusted the partner on a second trial irrespective of the partner’s incentives. These results demonstrate that while even school age children are mostly trusting, they are only beginning to spontaneously consider other’s incentives when interpreting the truthfulness of their utterances. However, after receiving false information only once they immediately switch to an untrusting attitude

Differential development and trainability of self-regulatory abilities among preschoolers

Self-regulation (SR) as well as self-regulated learning (SRL) show large interindividual variance in preschoolers. This variance may result in differential developmental trajectories. The present study aims to investigate whether a reduction in interindividual differences over time, which could previously be found for preschoolers' SR, is also present for SRL. Furthermore, the present study aims to explore whether preschool SRL training transfers to SR and whether training effects visible in SRL depend on initial performance. A sample of 94 preschoolers participated in this intervention study. Children were assigned to either a training group or to an active control group. Additionally, the sample was divided into high- and low-SRL preschoolers based on pretest SRL performance. Repeated measures ANCOVAs revealed that in the active control group, differences between high- and low-SRL preschoolers decreased over time. The training group showed a greater increase in SRL than the active control group. Training-induced increases did not vary between high- and low-SRL preschoolers. Additionally, increases in SR were identical for training and active control group. Further research on the transferability of preschool SRL training to SR is needed

Self-regulated learning as a mediator of the relation between executive functions and preschool academic competence

Executive functions (EF) and self-regulated learning (SRL) are processes for the goal-directed control of cognition and (learning) behavior that positively affect academic outcomes. Based on the finding that EF form the developmental basis for SRL, this study tested a model that assumes SRL as a mediator of the relationship between preschool EF and academic competence. Previous studies that found evidence for this mediation considered as predictors cool EF, which are important in emotionally neutral situations. However, since (pre) school-based learning is also associated with motivational incentives (e.g., praise from teachers and educators), this study aimed to test the validity of the above-mentioned mediation model using as predictors hot EF, which are important in emotional–motivational contexts. To this end, the constructs included in the model were crosssectionally examined using performance measures and parent ratings in a sample of n = 77 German preschoolers (Mage = 71.61 months, SD = 4.13; 51.9 % girls). Results show that SRL mediates the relationship between hot EF and academic competence. Methodological limitations of the present study and implications for research and practice are discussed

Magnetic Grueneisen ratio of the random transverse-field Ising chain

The magnetic analog of the Gr\"{u}neisen parameter, i.e., the magnetocaloric effect, is a valuable tool for studying field-tuned quantum phase transitions. We determine the magnetic Gr\"{u}neisen parameter of the one-dimensional random transverse-field Ising model, focusing on its low-temperature behavior at the exotic infinite-randomness quantum critical point and in the associated quantum Griffiths phases. We present extensive numerical simulations showing that the magnetic Gr\"{u}neisen parameter diverges logarithmically with decreasing temperature in the quantum Griffiths phase. It changes sign right at criticality. These results confirm a recent strong-disorder renormalization group theory. We also compare our findings to the behavior of the clean transverse-field Ising chain.Comment: 5 pages, 6 eps figures, submitted to Proc. of QCNP0

Universally diverging Grueneisen parameter and the magnetocaloric effect close to quantum critical points

At a generic quantum critical point, the thermal expansion $\alpha$ is more singular than the specific heat $c_p$. Consequently, the "Gr\"uneisen ratio'', \GE=\alpha/c_p, diverges. When scaling applies, \GE \sim T^{-1/(\nu z)} at the critical pressure $p=p_c$, providing a means to measure the scaling dimension of the most relevant operator that pressure couples to; in the alternative limit $T\to0$ and $p \ne p_c$, \GE \sim \frac{1}{p-p_c} with a prefactor that is, up to the molar volume, a simple {\it universal} combination of critical exponents. For a magnetic-field driven transition, similar relations hold for the magnetocaloric effect $(1/T)\partial T/\partial H|_S$. Finally, we determine the corrections to scaling in a class of metallic quantum critical points.Comment: 4 pages, 1 figure; general discussion on how the Grueneisen exponent measures the scaling dimension of the most relevant operator at any QCP is expande

An analytic model of the Gruneisen parameter at all densities

We model the density dependence of the Gruneisen parameter as gamma(rho) = 1/2 + gamma_1/rho^{1/3} + gamma_2/rho^{q}, where gamma_1, gamma_2, and q>1 are constants. This form is based on the assumption that gamma is an analytic function of V^{1/3}, and was designed to accurately represent the experimentally determined low-pressure behavior of gamma. The numerical values of the constants are obtained for 20 elemental solids. Using the Lindemann criterion with our model for gamma, we calculate the melting curves for Al, Ar, Ni, Pd, and Pt and compare them to available experimental melt data. We also determine the Z (atomic number) dependence of gamma_1. The high-compression limit of the model is shown to follow from a generalization of the Slater, Dugdale-MacDonald, and Vashchenko-Zubarev forms for the dependence of the Gruneisen parameter.Comment: 14 Pages, LaTeX, 5 eps figues; changes in the tex

On the relative importance of thermal and chemical buoyancy in regular and impact-induced melting in a Mars-like planet

We ran several series of two-dimensional numerical mantle convection simulations representing in idealized form the thermochemical evolution of a Mars-like planet. In order to study the importance of compositional buoyancy of melting mantle, the models were set up in pairs of one including all thermal and compositional contributions to buoyancy and one accounting only for the thermal contributions. In several of the model pairs, single large impacts were introduced as causes of additional strong local anomalies, and their evolution in the framework of the convecting mantle was tracked. The models confirm that the additional buoyancy provided by the depletion of the mantle by regular melting can establish a global stable stratification of the convecting mantle and throttle crust production. Furthermore, the compositional buoyancy is essential in the stabilization and preservation of local compositional anomalies directly beneath the lithosphere and offers a possible explanation for the existence of distinct, long-lived reservoirs in the martian mantle. The detection of such anomalies by geophysical means is probably difficult, however; they are expected to be detected by gravimetry rather than by seismic or heat flow measurements. The results further suggest that the crustal thickness can be locally overestimated by up to ~20 km if impact-induced density anomalies in the mantle are neglected.Comment: 29 pages, 10 figure