Abstraction and model evaluation in category learning

Thirty previously published data sets, from seminal category learning tasks, are reanalyzed using the varying abstraction model (VAM). Unlike a prototype-versus-exemplar analysis, which focuses on extreme levels of abstraction only, a VAM analysis also considers the possibility of partial abstraction. Whereas most data sets support no abstraction when only the extreme possibilities are considered, we show that evidence for abstraction can be provided using the broader view on abstraction provided by the VAM. The present results generalize earlier demonstrations of partial abstraction (Vanpaemel & Storms, 2008), in which only a small number of data sets was analyzed. Following the dominant modus operandi in category learning research, Vanpaemel and Storms evaluated the models on their best fit, a practice known to ignore the complexity of the models under consideration. In the present study, in contrast, model evaluation not only relies on the maximal likelihood, but also on the marginal likelihood, which is sensitive to model complexity. Finally, using a large recovery study, it is demonstrated that, across the 30 data sets, complexity differences between the models in the VAM family are small. This indicates that a (computationally challenging) complexity-sensitive model evaluation method is uncalled for, and that the use of a (computationally straightforward) complexity-insensitive model evaluation method is justified.     

Psychosoziale Risiken von Arbeitsplatzverlust und Arbeitslosigkeit

In a society centred around employment the strain that is associated with the experience of job loss is carrying considerable health risks. The empirical evidence of the differential effects of unemployment is reviewed in the framework of the victimization model and related to the background of health risks resulting from the former employment biography. Individual reactions are co-determined by a series of moderator variables which have been identified by differential unemployment research. From a health-related perspective also the indirect effects on the “victims-by-proxy”, e.g., the partners and children of unemployed people, have to be taken into consideration. Interventions can limit the psychosocial effects, especially if they are tailor-made and if they try to integrate elements of employment, qualification and social support. The necessity of the development of societal concepts of a “social convoy” (in the sense of a professional counselling) in occupational transitions is stressed. These should, however, start already during employment before the dismissal takes place. Theses concepts will take over social responsibility for restructuring and provide those being affected by dismissals with a legitimate claim for social support.     

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).     

Word associations: Norms for 1,424 Dutch words in a continuous task

This study describes the collection of a large set of word association norms. In a continuous word association task, norms for 1,424 Dutch words were gathered. For each cue, three association responses were obtained per participant. In total, an average of 268 responses were collected for each cue. We investigated the relationship with similar procedures, such as discrete association tasks and exemplar generation tasks. The results show that the use of a continuous task allows the study of weaker associations in comparison with a discrete task. The effects of the continuous tasks were investigated for set size and the availability characteristics of the responses, measured through word frequency, age of acquisition, and imageability. Finally, we compared our findings to those of a semantically constrained version of the association task in which participants generated responses within the domain of a semantic category. Results of this comparison are discussed. The Appendix cited in this article is available at www.psychonomic.org/archive.     

Criterion‐Related Validity of Dutch Police‐Selection Measures and Differences Between Ethnic Groups

This study investigated the criterion‐related validity of cognitive ability as well as non‐cognitive ability measures and differences between ethnic majority (N=2365) and minority applicants (N=682) in Dutch police officer selection. Findings confirmed the relatively low predictive validity of cognitive ability generally found for police jobs. Previous research reported no differential prediction. The present study, however, found small but systematic evidence for differences in validity for the ethnic majority and minority group of both cognitive and non‐cognitive measures. For the minority group, training performance appeared to be mainly predicted by the cognitive ability test. For the majority group, cognitive ability showed very little predictive power. Non‐cognitive ability variables appeared to be somewhat more predictive in this group.     

Intentional action and nearly certain success

Many philosophers have argued that a necessary condition on an action's being intentional is that the agent has the ability to alter the probabilities of the relevant outcome. These philosophers would hold that this condition is what allows us to deny that an agent, for example, intentionally rolls something other than five fives with a set of dice, despite that agent's being virtually sure that this will be the outcome of the roll. The current paper uses some examples to cast this explanation, and the necessity of the associated condition, into doubt. It then suggests that what actually differentiates intentional from unintentional action – in the examples that falsify the hypothesis about control – is to be found in the agent's representation of the processes by which the relevant outcomes are produced. In particular, the agent must represent the outcome as happening because of what she does.     

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.     

Feature integration in natural language concepts

Two experiments measured the joint influence of three key sets of semantic features on the frequency with which artifacts (Experiment 1) or plants and creatures (Experiment 2) were categorized in familiar categories. For artifacts, current function outweighed both originally intended function and current appearance. For biological kinds, appearance and behavior, an inner biological function, and appearance and behavior of offspring all had similarly strong effects on categorization. The data were analyzed to determine whether an independent cue model or an interactive model best accounted for how the effects of the three feature sets combined. Feature integration was found to be additive for artifacts but interactive for biological kinds. In keeping with this, membership in contrasting artifact categories tended to be superadditive, indicating overlapping categories, whereas for biological kinds, it was subadditive, indicating conceptual gaps between categories. It is argued that the results underline a key domain difference between artifact and biological concepts.