Apodemus sylvaticus (LOXT) is a suitable mouse strain for testing spatial memory retention in the Morris water maze

Information on the difference in cognitive function between laboratory and wild-caught mice is anecdotal and this question has not been systematically studied. Moreover, studying a wild-caught mouse strain per se may add information to the repertoire of mouse strains available. We aimed to study spatial memory in a wild mouse strain (Apodemus sylvaticus, AS) as compared to two individual laboratory mouse strains.Male AS (n = 20), CD1 (n = 19) and C57BL/6J mice (n = 19), 12–14 weeks old, were used in the experiments. The Morris water maze (MWM) was used for determination of spatial memory and time spent in the target quadrant at time points 5 (D5) and 12 days (D12) was evaluated. During the acquisition phase latency to reach the platform and path length to reach the platform was evaluated.Following four training days on day 5 (D5), time spent in the target quadrant was highest in AS > CD1 > C57BL/6J (P < 0.006). On day 12 (D12), time spent in the target quadrant was significantly higher in AS than in both other strains (P < 0.001).All animals learned the task and during the acquisition phase, latency to reach the platform as well as path length decreased significantly in AS.It is concluded that the AS is the most suitable strain for the evaluation of spatial memory in the MWM and is presenting with memory retention superior to laboratory mouse strains CD1 and C57BL/6J.     

Word associations: Network and semantic properties

A number of properties of word associations, generated in a continuous task, were investigated. First, we investigated the correspondence of word class in association cues and responses. Nouns were the modal word class response, regardless of the word class of the cue, indicating a dominant paradigmatic response style. Next, the word association data were used to build an associative network to investigate the centrality of nodes. The study of node centrality showed that central nodes in the network tended to be highly frequent and acquired early. Small-world properties of the association network were investigated and compared with a large English association network (Steyvers & Tenenbaum, 2005). Networks based on a multiple association procedure showed small-world properties despitebeing denser than networks based on a discrete task. Finally, a semantic taxonomy was used to investigate the composition of semantic types in association responses. The majority of responses were thematically related situation responses and entity responses referring to parts, shape, or color. Since the association task required multiple responses per cue, the interaction between generation position and semantic role could be investigated and discussed in the framework of recent theories of natural concept representations (Barsalou, Santos, Simmons, & Wilson, in press).     

Leisure time physical activity motives and smoking in adolescence

ObjectivesThe study aimed to gain a better understanding of the relationship between leisure time physical activity and smoking in adolescence by investigating adolescents' motives for participation in leisure time physical activity.MethodsThe study involved cross-sectional and longitudinal data from a postal survey involving 16–22-year old Danes. The hypothesized associations were examined using hierarchical logistic regression analyses.ResultsAn inverse association between participating in leisure time physical activity and smoking was found. Participation in leisure time physical activity for friendship or competition reasons were conditions that strengthened the inverse association between physical activity and smoking in males. In contrast, participation for the reason of losing weight or gaining self-esteem appeared to weaken the inverse association among females. In addition, the motives enjoyment, health and, in females, friendships and stress relief were associated with less smoking irrespective of participation level, while the motives self-esteem, losing weight and, in males, friendships were unrelated or even positively related to smoking.ConclusionsThe association between adolescents' leisure time physical activity and smoking behavior differs with the underlying motivation for the activity.     

Similar but not the same: A comparison of the utility of directly rated and feature-based similarity measures for generating spatial models of conceptual data

Spatial models are employed to represent conceptual data in a wide range of fields within psychological research. In order to generate spatial models, it is necessary to first obtain empirical similarity data. A number of methods are available for collecting these data, but little effort has been made to compare their relative utility. In this article, we compare directly rated and five feature-based similarity data types in regard to their ability to be adequately represented by a spatial model (representational goodness of fit), and the ability of the representations to predict three external empirical variables (predictive validity). The results indicate that the representational goodness of fit of the feature-based similarities is noticeably superior to the directly rated similarities, and that the predictions of representations derived from common feature similarity data are substantially more likely than the predictions of all of the alternative representations. It is suggested that these findings are highly relevant to researchers employing spatial models to represent conceptual data, given that direct pairwise ratings have generally been considered the “gold standard” means of obtaining empirical similarities.     

Mechanisms of developmental change in infant categorization

Computational models are tools for testing mechanistic theories of learning and development. Formal models allow us to instantiate theories of cognitive development in computer simulations. Model behavior can then be compared to real performance. Connectionist models, loosely based on neural information processing, have been successful in capturing a range of developmental phenomena, in particular on-line within-task category learning by young infants. Here we describe two new models. One demonstrates how age dependent changes in neural receptive field sizes can explain observed changes in on-line category learning between 3 and 10 months of age. The other aims to reconcile two conflicting views of infant categorization by focusing on the different task requirements of preferential looking and manual exploration studies. A dual-memory hypothesis posits that within-task category learning that drives looking time behaviors is based on a fast-learning memory system, whereas categorization based on background experience and assessed by paradigms requiring complex motor behavior relies on a second, slow-learning system. The models demonstrate how emphasizing the mechanistic causes of behaviors leads to discovery of deeper, more explanatory accounts of learning and development.     

Changing unbalanced coping profiles-A prospective controlled intervention trial in worksite health promotion

Abstract

Effective coping is based upon a broad variety of available strategies and a good balance between instrumental and palliative coping efforts. Thus, stress management training (SMT) should focus on broadening and balancing individual coping-profiles. This study investigated changes in coping profiles after participation in SMT at the worksite. The sample consisted of 82 healthy working persons who participated in a 12-week-SMT and 55 matched controls without intervention. The SMT consisted of six training elements: three of them (assertiveness, cognitive restructuring and time management) addressed instrumental coping and the other three (relaxation, physical activity and scheduling of pleasant activities) focussed on palliative coping. All subjects filled in standardized questionaires on coping, well-being and strain before and after the training. Cluster analyses performed on initial coping scores resulted in a 3-cluster solution: (1) “active flexible coping” (n = 53), (2) “problem-focused coping” (n = 40) and (3) “resignative avoidant coping” (n = 44). Analyses of covariance revealed that SMT-participants of Cluster 2 showed significant improvements regarding emotion-focused coping and those of Cluster 3 regarding problem-focused coping compared to controls of the same cluster. There were also significant associations between these clusterspecific changes of coping and improvements of well-being. In consequence, the SMT improved coping by supplementing one-sided initial coping-profiles.     

Introduction to the special issue on formal modeling of semantic concepts

We introduce the special issue on formal models of semantic concepts. After outlining the research questions that motivated the issue, we summarize the rich set of data provided by the Leuven Natural Concepts Database, and provide an overview of the seven research articles in the special issue. Each of these articles applies a formal modeling approach to one or more parts of the database, attempting to further our understanding of how people represent and use semantic concepts.     

Retention of autobiographical memories: An Internet-based diary study

In this online study we examined the retention of recent personal events using an Internet-based diary technique. Each participant (N=878) recorded on a website one recent personal event and was contacted after a retention interval that ranged between 2 and 46 days. We investigated how well the participants could recall the content, time, and details of their recorded event. We found a classic retention function. Details of the events were forgotten more rapidly than the content and the time of the events. There were no differences between the forgetting rates of the “who”, “what” and “where” elements of the content component. Reminiscing, social sharing, pleasantness, and frequency of occurrence aided recall, but surprisingly importance and emotionality did not. They were, however, strongly associated with reminiscing and social sharing.     

Begging the Question: A Qualified Defense

This discussion examines two of the central notions at work in Sterba’s From Rationality to Equality: question-beggingness, and the notion of a rational requirement. I point out that, against certain unreasonable positions, begging the question is a perfectly reasonable option. I also argue that if we use the sense of “rational requirement” that philosophers ought (and tend) to have in mind when defending the idea that morality is rationally required, then Sterba has not succeed in defending this idea. Rather, he has at most demonstrated the rational preferability of morality over two other positions: an extreme egoism, and a very particular form of altruism. But another position exists: one that holds altruistic reasons to exist, and to be capable of justifying sacrifices, but that also holds that they do not require us to sacrifice our interests in the way that morality sometimes does require.