Hungry pigeons make suboptimal choices, less hungry pigeons do not

Hungry animals will often choose suboptimally by being attracted to reliable signals for food that occur infrequently (they gamble) over less reliable signals for food that occur more often. That is, pigeons prefer an option that 50?% of the time provides them with a reliable signal for the appearance of food but 50?% of the time provides them with a reliable signal for the absence of food (overall 50?% reinforcement) over an alternative that always provides them with a signal for the appearance of food 75?% of the time (overall 75?% reinforcement). The pigeons appear to choose impulsively for the possibility of obtaining the reliable signal for reinforcement. There is evidence that greater hunger is associated with greater impulsivity. We tested the hypothesis that if the pigeons were less hungry, they would be less impulsive and, thus, would choose more optimally (i.e., on the basis of the overall probability of reinforcement). We found that hungry pigeons choose the 50?% reinforcement alternative suboptimally but less hungry pigeons prefer the more optimal 75?% reinforcement. Paradoxically, pigeons that needed the food more received less of it. These findings have implications for how level of motivation may also affect human suboptimal choice (e.g., purchase of lottery tickets and playing slot machines).     

Outliers and Influential Observations in Exponential Random Graph Models

We discuss measuring and detecting influential observations and outliers in the context of exponential family random graph (ERG) models for social networks. We focus on the level of the nodes of the network and consider those nodes whose removal would result in changes to the model as extreme or “central” with respect to the structural features that “matter”. We construe removal in terms of two case-deletion strategies: the tie-variables of an actor are assumed to be unobserved, or the node is removed resulting in the induced subgraph. We define the difference in inferred model resulting from case deletion from the perspective of information theory and difference in estimates, in both the natural and mean-value parameterisation, representing varying degrees of approximation. We arrive at several measures of influence and propose the use of two that do not require refitting of the model and lend themselves to routine application in the ERGM fitting procedure. MCMC p values are obtained for testing how extreme each node is with respect to the network structure. The influence measures are applied to two well-known data sets to illustrate the information they provide. From a network perspective, the proposed statistics offer an indication of which actors are most distinctive in the network structure, in terms of not abiding by the structural norms present across other actors.     

Assessing Specific Effects of Inpatient Group Psychotherapy

Abstract

This article will examine how the psychoanalytic idea of containing can be used in group therapy to form a conceptual bridge such that the group dynamics are not simplistically reduced to individual dynamics, nor that the individual is lost in the “group–as–a–whole” concept. I take the concept of “containing” as versatile in the sense that Bion (1970) meant it to be—that is, the psychological phenomenon of containment is manifest at various system levels: intrapsychic, interpersonal, group, and societal. This article will explore how far this “bridging concept” can be pursued to understand groups theoretically. The article will review various forms of containing, following Bion’s ideas, and in particular a therapeutic, or flexible, form in contrast to rigid and fragile forms.     

Structural equation modelling of human judgement

Structural equation modelling (SEM) is outlined and compared with two non-linear alternatives, artificial neural networks and “fast and frugal” models. One particular non-linear decision-making situation is discussed, that exemplified by a lexicographic semi-order. We illustrate the use of SEM on a dataset derived from 539 volunteers' responses to questions about food-related risks. Our conclusion is that SEM is a useful member of the armoury of techniques available to the student of human judgement: it subsumes several multivariate statistical techniques and permits their flexible combination, and it provides robust goodness-of-fit statistics and is available in (generally) easy-to-use computer packages. Although the number of tasks for which SEM provides a persuasive psychological model is small, it is very useful in identifying the important variables and their inter-relations that contribute to task performance, and thus can constitute a valuable intermediate staging point between raw data and a fully fledged psychological theory.     

Experimental and Quasi-Experimental Designs in Visitor Studies: A Critical Reflection on Three Projects

Identifying causal relationships is an important aspect of research and evaluation in visitor studies, such as making claims about the learning outcomes of a program or exhibit. Experimental and quasi-experimental approaches are powerful tools for addressing these causal questions. However, these designs are arguably underused in visitor studies. In this article, we offer examples of the use of experimental and quasi-experimental designs in science museums to aide investigators interested in expanding their methods toolkit and increasing their ability to make strong causal claims about programmatic experiences or relationships among variables. Using three designs from recent research (fully randomized experiment, posttest only quasi-experimental design with comparison condition, and posttest with independent pretest design), we discuss challenges and tradeoffs related to feasibility, participant experience, alignment with research questions, and internal and external validity. We end the article with broader reflections on the role of experimental and quasi-experimental designs in visitor studies.     

Advocacy processes in mental health: a qualitative study

Advocates perform an important role in representing the rights of mental health consumers, especially since mental health consumers are often marginalized. Little is known about the processes advocates use to assist mental health consumers in navigating the health care system. This study details the manner in which advocates work together with mental health consumers and health professionals through presenting a qualitative synthesis of 60 case records. Four main themes emerged: negotiating on behalf of consumers during meetings with health professionals; liaising between consumers and health professionals outside of meetings; supporting consumer decision making without the involvement of health professionals; and involvement in legal processes. The findings of this study demonstrated that advocates were primarily oriented toward the protection of negative rights, but they also promoted positive rights.