Is Communication Complexity Physical?

Recently, Brassard et. al. conjectured that the fact that the maximal possible correlations between two non-local parties are the quantum-mechanical ones is linked to a reasonable restriction on communication complexity. We provide further support for the conjecture in the multipartite case. We show that any multipartite communication complexity problem could be reduced to triviality, had Nature been more non-local than quantum-mechanics by a quite small gap for any number of parties. Intriguingly, the multipartite nonlocal-box that we use to show the result corresponds to the generalized Bell inequality that manifests maximal violation in respect to a local hidden-variable theory

Enhanced dispersion interaction in confined geometry

The dispersion interaction between two point-like particles confined in a dielectric slab between two plates of another dielectric medium is studied within a continuum (Lifshitz) theory. The retarded (Casimir-Polder) interaction at large inter-particle distances is found to be strongly enhanced as the mismatch between the dielectric permittivities of the two media is increased. The large-distance interaction is multiplied due to confinement by a factor of $(33\gamma^{5/2}+13\gamma^{-3/2})/46$ at zero temperature, and by $(5\gamma^2+\gamma^{-2})/6$ at finite temperature, \gamma=\ein(0)/\eout(0) being the ratio between the static dielectric permittivities of the inner and outer media. This confinement-induced amplification of the dispersion interaction can reach several orders of magnitude.Comment: 4 page

The hierarchical competing systems model provides a process account of social decision making

We applaud Richardson, Mulvey, and Killen’s [2012] application of the hierarchical competing systems model (HCSM) to models of social decision making. The HCSM is a framework of the development of executive function that was formulated to account for patterns of behavior in infant and toddler search tasks. However, the principles of the model are relevant across a wide range of domains throughout the lifespan [Marcovitch & Zelazo, 2009]. According to the HCSM framework, behavior (or decision making) results from the joint contributions of a habit system (appropriately relabeled ‘experience’ by Richardson et al.) and a representational system. In turn, the act of reflection – defined as representing a representation – strengthens the influence of the representational system to the point where it can override the influence of the habit system. Importantly, reflection is not always needed for an individual to act in a novel, appropriate fashion (i.e., this can occur through the influences of unreflective representations). That said, the presence of reflection allows for the modification of behavior (or preexisting rationales for decision making) based solely on endogenous processes, even when these endogenous processes can be triggered from environmental events. In short, we argue that unexpected changes in the environment have the potential to initiate reflection, provided that the individual is attentive, capable of processing the nature of the disturbance, and motivated to reconcile the situation

Self-Reflection and the Cognitive Control of Behavior: Implications for Learning

In this article, we suggest that self-reflection and self-control--studied under the rubric of "executive function" (EF)—have the potential to transform the way in which learning occurs, allowing for the relatively rapid emergence of new behaviors. We describe 2 lines of research that indicate that reflecting on a task and its affordances helps children to respond flexibly in a more top-down fashion despite interference from prior learning or perceptually salient aspects of the task. Research on A-not-B tasks with infants and young children revealed that postswitch flexibility is an inverted U-shaped function of number of preswitch trials. Overlearning may provide additional opportunities for reflection, in part by freeing up cognitive resources as behavior becomes automatized. Findings from the Flexible Item Selection Task with preschoolers and adults revealed that, although labeling the relevant dimension facilitates performance, performance declines when participants are prohibited from labeling. Labeling one's perspective on a situation not only helps make that perspective an explicit object of consideration, but it may also help children access more abstract conceptual descriptions of a stimulus Research on EF has broad implications for the way in which human learning differs from learning in other species and the way in which human learning may change over the course of development

Young Children’s Ability to Use Ordinal Labels in a Spatial Search Task

The use and understanding of ordinal terms (e.g., “first” and “second”) is a developmental milestone that has been relatively unexplored in the preschool age range. In the present study, 4- and 5-year-olds watched as a reward was placed in one of three train cars labeled by the experimenter with an ordinal (e.g., first car), color (e.g., brown car), or generic label (e.g., that car). Results revealed that 4-year-olds actually had more difficulty retrieving the reward once occluded under identical tunnels when they were provided with ordinal labels compared to color and generic labels. Search performance improved with age and showed dramatic growth in the ordinal-label condition from 4 to 5 years of age. Results are discussed with regard to children’s ability to use verbal labels of developing conceptual knowledge (i.e., linked to ordinality) to guide behavior

Goal neglect and working memory capacity in 4- to 6-year-old children

Goal neglect is the phenomenon of failing to execute the momentary demands of a task despite understanding and being able to recall the task instructions. Successful goal maintenance is more likely to occur in adults with high working memory capacity (WMC) who can keep rules mentally accessible while performing the task. The current study predicted that goal neglect would also be related to WMC in children. It assessed thirty-seven 4-year-old and twenty-eight 6-year-old children on the goal neglect version of the Dimensional Change Card Sort, and 3 tasks that measure WMC. As predicted, children with higher WMC scores were more likely to maintain goals adequately for task performance. The findings are consistent with a 2-factor model of working memory and its development

Integration of Behavioral Frequency and Intention Information in Young Children's Trait Attributions

Two experiments examined three- to six-year-olds' use of frequency and intention information to make trait attributions and behavioral predictions. In experiment 1, participants were told a story about an actor who behaved positively once or four times on purpose or incidentally. Children were most likely to make trait-consistent behavioral predictions after hearing about several positive, intentional behaviors. Trait attributions were largely positive. Experiment 2 examined children's use of the same cues concerning negative behavioral outcomes. Participants tended to predict that actors who engaged in negative behavior would do so again, irrespective of intention, although younger children required more exemplars than older children. Participants were most likely to make negative trait attributions after hearing about multiple intentional behaviors; however, there was reluctance with age to describe actors as mean. Implications for children's ‘theory of personality’ are discussed

Integration of behavioral frequency and intention information in young children’s trait attributions.

Two experiments examined three- to six-year-olds' use of frequency and intention information to make trait attributions and behavioral predictions. In experiment 1, participants were told a story about an actor who behaved positively once or four times on purpose or incidentally. Children were most likely to make trait-consistent behavioral predictions after hearing about several positive, intentional behaviors. Trait attributions were largely positive. Experiment 2 examined children's use of the same cues concerning negative behavioral outcomes. Participants tended to predict that actors who engaged in negative behavior would do so again, irrespective of intention, although younger children required more exemplars than older children. Participants were most likely to make negative trait attributions after hearing about multiple intentional behaviors; however, there was reluctance with age to describe actors as mean. Implications for children's ‘theory of personality’ are discussed

Use it or lose it: Examining preschoolers’ difficulty in maintaining and executing a goal

Individuals with low working memory capacity (e.g. preschoolers) are more prone to goal neglect, or a failure to execute a goal even though it is understood. We examined the role of goal neglect in performance on the Dimensional Change Card Sort by including ‘redundant’ cards that could be sorted without attending to the rules, as well as the traditional ‘conflict’ cards that encouraged awareness of the rules. In Experiment 1, 4- and 5-year-old children were administered two card sorts that differed on the proportion of redundant cards presented (20% vs. 80%). Children neglected the goal more often when faced with a preponderance of redundant cards, suggesting that consistent attention to the rules leads to goal maintenance. In Experiment 2, results were replicated even when the post-switch rules were repeated on every trial. Implications for the development of working memory are discussed

Process Tomography for Systems in a Thermal State

We propose a new method for implementing process tomography that is based on the information extracted from temporal correlations between observables, rather than on state preparation and state tomography. As such, the approach is applicable to systems that are in a mixed state, and in particular to thermal states. We illustrate the method for an arbitrary evolution described by Kraus operators, as well as for simpler cases such as a general Gaussian channels, and qubit dynamics