Self-organizing continuous attractor network models of hippocampal spatial view cells

Single neuron recording studies have demonstrated the existence of hippocampal spatial view neurons which encode information about the spatial location at which a primate is looking in the environment. These neurons are able to maintain their firing even in the absence of visual input. The standard neuronal network approach to model networks with memory that represent continuous spaces is that of continuous attractor networks. It has recently been shown how idiothetic (self-motion) inputs could update the activity packet of neuronal firing for a one-dimensional case (head direction cells), and for a two-dimensional case (place cells which represent the place where a rat is located). In this paper, we describe three models of primate hippocampal spatial view cells, which not only maintain their spatial firing in the absence of visual input, but can also be updated in the dark by idiothetic input. The three models presented in this paper represent different ways in which a continuous attractor network could integrate a number of different kinds of velocity signal (e.g., head rotation and eye movement) simultaneously. The first two models use velocity information from head angular velocity and from eye velocity cells, and make use of a continuous attractor network to integrate this information. A fundamental feature of the first two models is their use of a 'memory trace' learning rule which incorporates a form of temporal average of recent cell activity. Rules of this type are able to build associations between different patterns of neural activities that tend to occur in temporal proximity, and are incorporated in the model to enable the recent change in the continuous attractor to be associated with the contemporaneous idiothetic input. The third model uses positional information from head direction cells and eye position cells to update the representation of where the agent is looking in the dark. In this case the integration of idiothetic velocity signals is performed in the earlier layer of head direction cells.     

Realist ethical naturalism for ethical non-naturalists

It is common in metaethics today to draw a distinction between “naturalist” and “non-naturalist” versions of moral realism, where the former view maintains that moral properties are natural properties, while the latter view maintains that they are non-natural properties instead. The nature of the disagreement here can be understood in different ways, but the most common way is to understand it as a metaphysical disagreement. In particular, the disagreement here is about the reducibility of moral properties, where the “naturalists” maintain that moral properties are in some way reducible to the lower-level natural properties on which they supervene, while the “non-naturalists” maintain that moral properties are sui generis and robustly irreducible. In this paper I present a novel version of realist ethical naturalism—a view that I call Emergentist Ethical Naturalism—that reveals this common way of understanding the distinction between naturalism and non-naturalism to be flawed by combining a commitment to ethical naturalism with a commitment to the sui generis and robustly irreducible nature of moral properties that typically defines non-naturalism. Then, after presenting the theory and addressing a few worries that one might have about it, I show how it offers some novel, emergence-based responses to the various supervenience challenges that plague moral realism and thereby gives the ethical naturalist a robustly non-reductive option for dealing with these challenges.     

Grief Therapy and the Reconstruction of Meaning: From Principles to Practice

Viewed from a constructivist perspective, grieving is a process of reconstructing a world of meaning that has been challenged by loss. Although most people successfully navigate bereavement and retain or return to pre-loss levels of functioning, a significant proportion struggle with protracted grief, and are unable to find meaning in the wake of an unsought transition. For these individuals, constructivist therapists have a number of strategies at their disposal that foster meaning making and help clients reestablish a coherent self-narrative that integrates the loss, while also permitting their life story to move forward along new lines. After reviewing theory and evidence that scaffolds this constructivist conceptualization, this article draws on excerpts of therapy with two bereaved clients to illustrate how narrative retelling, therapeutic writing, a focus on metaphorical language, and the use of visualization can all be viable strategies in helping individuals reconstruct meaning in the wake of bereavement.     

The Effects of Limited and Conflicting Stereotypic information on Group Categorization in Northern Ireland1

The process of group categorization, as suggested by Tajfel and Turner's (1979) theory of intergroup comparison, was examined under conditions of intergroup conflict in Northern Ireland. The theory predicts that under “normal” conditions groups have a need to distinguish themselves from others. The present study investigates how individuals in Northern Ireland under extreme environmental pressures to identify both their own and other groups, can use learned stereotypic cues in making such categorizations. Results suggested that such limited information was highly effective in the process of categorization, with both Protestant and Catholic subjects exhibiting significant agreement and confidence in identifying unknown persons on the basis of stereotypic cues Conflicting information was found to reduce subject's confidence levels, with conflicting Catholic cues being more disruptive than Protestant ones     

Bayesian inference for the information gain model

One of the most popular paradigms to use for studying human reasoning involves the Wason card selection task. In this task, the participant is presented with four cards and a conditional rule (e.g., “If there is an A on one side of the card, there is always a 2 on the other side”). Participants are asked which cards should be turned to verify whether or not the rule holds. In this simple task, participants consistently provide answers that are incorrect according to formal logic. To account for these errors, several models have been proposed, one of the most prominent being the information gain model (Oaksford & Chater, Psychological Review, 101, 608–631, 1994). This model is based on the assumption that people independently select cards based on the expected information gain of turning a particular card. In this article, we present two estimation methods to fit the information gain model: a maximum likelihood procedure (programmed in R) and a Bayesian procedure (programmed in WinBUGS). We compare the two procedures and illustrate the flexibility of the Bayesian hierarchical procedure by applying it to data from a meta-analysis of the Wason task (Oaksford & Chater, Psychological Review, 101, 608–631, 1994). We also show that the goodness of fit of the information gain model can be assessed by inspecting the posterior predictives of the model. These Bayesian procedures make it easy to apply the information gain model to empirical data. Supplemental materials may be downloaded along with this article from .     

Gender recognition from point-light walkers

Point-light displays of human gait provide information sufficient to recognize the gender of a walker and are taken as evidence of the exquisite tuning of the visual system to biological motion. The authors revisit this topic with the goals of quantifying human efficiency at gender recognition. To achieve this, the authors first derive an ideal observer for gender recognition on the basis of center of moment (J. E. Cutting, D. R. Proffitt, & L. T. Kozlowski, 1978) and, with the use of anthropometric data from various populations, show optimal recognition of approximately 79% correct. Next, they perform a meta-analysis of 21 experiments examining gender recognition, obtaining accuracies of 66% correct for a side view and 71% for other views. Finally, results of the meta-analysis and the ideal observer are combined to obtain estimates of human efficiency at gender recognition of 26% for the side view and 47% for other views.     

成人日常问题解决的老化研究

日常问题解决能力是近十几年来老年心理学中研究比较活跃的一个领域。本文介绍了有关日常问题解决研究的四种理论,即心理测量的智力内隐理论、形式后思维的辨证思维理论、信息加工理论和社会认知与智慧理论,及其初步的研究成果,并进一步指出在理论上整合和在实践中开展干预的研究方向。     

Group affiliation and confidence in denominational categorization in Northern Ireland

The effects of group affiliation on group categorization confidence were examined in Northern Ireland. Subjects were presented with stereotypic name, school and location cues and a group affiliation scale devised by Brown, Condor, Mathews, Wade and Williams (1986). The results suggest that group affiliation has no effect on subjects' confidence in making denominational categorizations.     

Evidencing superdiversity in the census and beyond

Abstract

Starting from the proposition, in both my own work and that of Steve Vertovec, that there is something about superdiverse neighbourhoods or societies that is qualitatively different from those that are merely diverse, this paper asks whether it is possible to identify religious superdiversity within quantitative population data, such as the census in England and Wales, in order to test such a proposition. In doing this the paper will ask whether it is possible to find any evidence for superdiversity, as Vertovec defines it, in data sets such as the census and whether such data can help to identify where to set the boundary between ‘diversity’ and ‘superdiversity’. The paper will then explore what would need to be measured in order to designate an area as superdiverse in religious terms and whether the census data can offer any material that can be used for this purpose. The author concludes by suggesting that we need a range of methods, both quantitative and qualitative, to define any area as superdiverse and that it is only in this way that we can begin to test the kind of hypothesis offered by the author at the start of the paper.     

A 10-day developmental voyage: converging evidence from three studies showing that self-esteem may be elevated and maintained without negative outcomes

Empirical evidence shows that educational experiences in the context of the outdoors lead to elevated self-esteem. Although elevated self-esteem is widely assumed to promote beneficial outcomes, recent evidence suggests that elevated self-esteem may also facilitate a variety of negative outcomes (i.e., increased prejudice, aggression, drug and alcohol abuse). The current research was conducted in order to examine whether one type of outdoor educational experience—a 10-day developmental voyage—could elevate adolescents’ self-esteem without also elevating negative outcomes. The data from three separate studies are reported. Study one revealed that adolescents who undertook the voyage manifested elevated self-esteem and decreased gender prejudice (i.e., less negative ratings of opposite sex outgroup members). Study two replicated these findings and further demonstrated that these effects were maintained 4–5 months following the voyage. In study three, in addition to self-esteem, risky attitudes (i.e., towards drug and alcohol use), physical aggression, verbal aggression, racial and gender bias were also examined. Adolescents again showed elevated self-esteem that was maintained 4–5 months following the voyage. There were no changes in risky attitudes, aggression, or racial and gender bias. Taken together these results indicate that taking part in a 10-day developmental voyage—can lead to an elevation in self-esteem, that is maintained over time and which does not facilitate a variety of negative outcomes.