Visual discrimination,sequential learning and memory retrieval in the Australian desert ant <Emphasis Type="Italic">Melophorus bagoti</Emphasis>

Bees, wasps and ants—so-called central-place foragers—need potent homing strategies to return to their nest. Path integration and view-based landmark guidance are the key strategies for the ants’ navigation. For instance, they memorise different views in a sequence (sequential memory) but also have a step counter that informs them about the covered distance during each foraging trip (odometer). The sequential memory and the odometer information can act as contextual cues during travel for retrieving the appropriate stored view. When and which cue is used at different stages and lengths of the foraging trips is still unknown. In this study, we examined how the Australian desert ant Melophorus bagoti uses sequential memory and odometric information to retrieve visual memories. Using a set-up made out of channels and two-choice boxes (Y-mazes), we demonstrate first that M. bagoti foragers are able to learn and discriminate a variety of visual stimuli in a sequence of views along the inbound trip back to the nest. We then forced the homing ants to encounter a fixed sequence of two visual patterns during their inbound trips. By manipulating the position and distance of the visual stimuli and decision boxes, we could set the two contextual cues (sequential memory and odometer) into conflict. After the short 4-m outbound distance, a preference for odometric information as a contextual cue was found, but after the long 8-m outbound distance, ants relied primarily on their sequential memory retrieval. Odometer precision deteriorates with increasing travel distance, and accordingly, our findings imply that desert ants may be relying on the most reliable contextual cue for retrieving visual memories.     

Punitive versus compensatory reactions to injustice: Emotional antecedents to third-party interventions

The almost exclusive focus on punishment and inattention to compensatory alternatives in studies involving experimental games may yield patterns that do not accurately reflect how and when people respond to injustice, particularly if punishment and compensation are not psychologically equivalent approaches to justice restoration. In the current study, we examined participants' preference for punitive and compensatory actions, while also exploring emotional determinants and boundary conditions. Our results indicated that participants actually compensated victims more than they punished offenders and that the majority of participants assigned both. Furthermore, although both interventions were associated with emotional experiences of moral outrage toward the offender, self-focused emotions reflecting feelings of threat only predicted compensation and only when victims were aware that they had been victimized. These findings augment our understanding of third-party interventions, emphasizing the importance of considering response alternatives when studying the psychology of justice.     

Geometry, features, and panoramic views: ants in rectangular arenas

When tested in rectangular arenas, the navigational behavior of the ant Gigantiops destructor can produce results similar to vertebrates. Such results are usually interpreted as supporting the ability of animals to segregate spatial geometry and features. Here, we combine a detailed analysis of ants' paths with panoramic images taken from the ant's perspective that can serve as a basis for developing view-based matching models. The corner choices observed in ants were better predicted by the use of panoramic views along with a simple matching process [rotational image difference function (rIDF)] than by models assuming segregation of geometry and features (G/F). Our view-based matching model could also explain some aspects of the ants' path (i.e., initial direction, length) resulting from the different visual conditions, suggesting that ants were using such a taxon-like strategy. Analyzed at the individual level, the results show that ants' idiosyncratic paths tend to evolve gradually from trial to trial, revealing that the ants were partially updating their route memory after each trial. This study illustrates the remarkable flexibilities that can arise from the use of taxon-like strategies and stresses the importance of considering them in vertebrates.     

A reinforcement learning diffusion decision model for value-based decisions

Psychonomic Bulletin & Review - Psychological models of value-based decision-making describe how subjective values are formed and mapped to single choices. Recently, additional efforts have...     

A New Game Equivalence,its Logic and Algebra

We present a new notion of game equivalence that captures basic powers of interacting players. We provide a representation theorem, a complete logic, and a new game algebra for basic powers. In doing so, we establish connections with imperfect information games and epistemic logic. We also identify some new open problems concerning logic and games.

     

Psychopathy scores and violence among juvenile offenders: a multi-measure study

This study examined the relations between psychopathy scores and violent behavior in 113 incarcerated adolescents. We compared the results of four different instruments designed to assess psychopathy features among juveniles-the Psychopathy Checklist: Youth Version (PCL:YV), two versions of the Antisocial Processes Screening Device (APSD), and a Psychopathy Content scale on the Millon Adolescent Clinical Inventory (MACI). We found that PCLY:YV scores were significantly correlated with violent offense history, unadjudicated violence, and institutional violence, as well as measures of the severity and instrumentality of prior violence. Receiver operating characteristic analyses generated statistically significant effect sizes (AUC values) ranging from 0.64 to 0.79. The three other measures generated statistically significant correlations with one or more of the violence criteria, although correlations and effect sizes tended to be smaller in magnitude. Our results offer some support for the validity of these measures of psychopathic features, and the value of the PCL:YV in particular, with respect to short-term measures of violence outcome among juvenile offenders.     

Long-term motor programming improvements occur via concatenation of movement sequences during random but not during blocked practice

According to S. T. Klapp (1995, 1996), extensive practice serves to induce the concatenation of multiple-element responses. One benefit of the chunking process, argued Klapp, is more efficient execution of motor programming. The authors conducted the present study with 30 participants to investigate that proposition. The chunking process was found to be very transient following some practice regimes. Specifically, compared with exposure to random practice, extensive blocked practice resulted in only temporary movement sequence consolidation. The present results provide support for the claim that random practice not only leads to improvements in the completion of intratrial movement planning processes but also affects the structure of the memory developed during practice. Both components are important contributors to long-term improvements in movement preparation associated with a high contextual-interference practice condition.     

Distributional Models of Category Concepts Based on Names of Category Members

Cognitive scientists have long used distributional semantic representations of categories. The predominant approach uses distributional representations of category-denoting nouns, such as “city” for the category city. We propose a novel scheme that represents categories as prototypes over representations of names of its members, such as “Barcelona,” “Mumbai,” and “Wuhan” for the category city. This name-based representation empirically outperforms the noun-based representation on two experiments (modeling human judgments of category relatedness and predicting category membership) with particular improvements for ambiguous nouns. We discuss the model complexity of both classes of models and argue that the name-based model has superior explanatory potential with regard to concept acquisition.     

Expressivism,meaning, and all that

Abstract

It has recently been suggested that meta-normative expressivism is best seen as a meta-semantic, rather than a semantic view. One strong motivation for this is that expressivism becomes, thereby, compatible with truth-conditional semantics. While this approach is promising, however, many of its details are still unexplored. One issue that still needs to be explored in particular, is what accounts of propositional contents are open to meta-semantic expressivists. This paper makes progress on this issue by developing an expressivist-friendly deflationary account of such contents.     

An Analysis of Factors Influencing the International Migration of Indian Nurses

Based on our survey conducted in Tamil Nadu, this paper analyses the characteristics of Indian migrant nurses and the factors influencing their migration. India is considered the second largest exporter of nurses after the Philippines. Many Indian nurses have migrated to work in OECD countries, the Gulf countries and some ASEAN countries. While Indian nurses are migrating overseas to fill shortages at their destinations, India has itself been suffering from an acute scarcity of nurses since its independence in 1947. Therefore, the large scale of nurse migration is a serious threat to the Indian healthcare system. The results of the survey imply that international migration by nurses can be explained in part by the gap between the private sector and the public sector in terms of salary and working environment. Since the impact of social status on the migration decisions of nurses has lessened, economic factors are the crucial determinant of international migration of nurses. Policy intervention in this area is the necessary first step to solving this long-standing problem. The priority in any policies formulated should be given to nurses working in the private sector whose salaries are considerably lower than those in the public sector and whose voices are unheard.