A tutorial on kernel methods for categorization

The abilities to learn and to categorize are fundamental for cognitive systems, be it animals or machines, and therefore have attracted attention from engineers and psychologists alike. Modern machine learning methods and psychological models of categorization are remarkably similar, partly because these two fields share a common history in artificial neural networks and reinforcement learning. However, machine learning is now an independent and mature field that has moved beyond psychologically or neurally inspired algorithms towards providing foundations for a theory of learning that is rooted in statistics and functional analysis. Much of this research is potentially interesting for psychological theories of learning and categorization but also hardly accessible for psychologists. Here, we provide a tutorial introduction to a popular class of machine learning tools, called kernel methods. These methods are closely related to perceptrons, radial-basis-function neural networks and exemplar theories of categorization. Recent theoretical advances in machine learning are closely tied to the idea that the similarity of patterns can be encapsulated in a positive definite kernel. Such a positive definite kernel can define a reproducing kernel Hilbert space which allows one to use powerful tools from functional analysis for the analysis of learning algorithms. We give basic explanations of some key concepts—the so-called kernel trick, the representer theorem and regularization—which may open up the possibility that insights from machine learning can feed back into psychology.     

Motivation gains of inferior group members: a meta-analytical review

In recent years, a growing number of studies have demonstrated that individuals can exert higher motivation when working in a group compared to working individually. This is particularly true for less capable, inferior group members. To aggregate these findings and to examine preconditions as well as moderating influences on motivation gains of inferior group members, the authors conducted a meta-analysis (17 studies, N=2,240). Results indicated that the overall motivation gain effect of inferior group members observed is moderate and significant (g=.60). Moderator analyses revealed substantial influences of task structure, performance information, physical presence, gender, and task type.     

Auditory event files: Integrating auditory perception and action planning

The features of perceived objects are processed in distinct neural pathways, which call for mechanisms that integrate the distributed information into coherent representations (the binding problem). Recent studies of sequential effects have demonstrated feature binding not only in perception, but also across (visual) perception and action planning. We investigated whether comparable effects can be obtained in and across auditory perception and action. The results from two experiments revealed effects indicative of spontaneous integration of auditory features (pitch and loudness, pitch and location), as well as evidence for audio—manual stimulus—response integration. Even though integration takes place spontaneously, features related to task-relevant stimulus or response dimensions are more likely to be integrated. Moreover, integration seems to follow a temporal overlap principle, with features coded close in time being more likely to be bound together. Taken altogether, the findings are consistent with the idea of episodic event files integrating perception and action plans.     

Falsificationism and Statistical Learning Theory: Comparing the Popper and Vapnik-Chervonenkis Dimensions

We compare Karl Popper’s ideas concerning the falsifiability of a theory with similar notions from the part of statistical learning theory known as VC-theory. Popper’s notion of the dimension of a theory is contrasted with the apparently very similar VC-dimension. Having located some divergences, we discuss how best to view Popper’s work from the perspective of statistical learning theory, either as a precursor or as aiming to capture a different learning activity.     

Psychotherapeutenausbildung aus Sicht der Absolventen

Background

A survey was performed to assess the current situation in education and to identify critical issues 10 years after the inception of the psychotherapy act in Germany.

Methods

In August 2008 all non-medical psychotherapists who had graduated since 2002 according the psychotherapy act were invited to take part in the survey and a total of 863 persons participated. The answers from 666 could be evaluated corresponding to a participation rate of 20%.

Results

A total of 57.6% of the graduates had completed a full-time training and approximately 50% of the graduates had completed the training within the allotted time. In the majority of cases evaluation occurred only for the theoretical courses. During the practical work (PT I) 36.8% of the graduates did not receive any salary or remuneration, 82% had their own field of activity and of these 38% treated patients without the presence of qualified tutor.

Conclusions

The training often lasts longer than intended, the financial situation in the PT I is exceptionally critical and in clear contrast to the field of activity in this section of training. Further detailed results will be presented and discussed.     

How Social Are Task Representations?

ABSTRACT— The classical Simon effect shows that actions are carried out faster if they spatially correspond to the stimulus signaling them. Recent studies revealed that this is the case even when the two actions are carried out by different people; this finding has been taken to imply that task representations are socially shared. In work described here, we found that the "interactive" Simon effect occurs only if actor and coactor are involved in a positive relationship (induced by a friendly-acting, cooperative confederate), but not if they are involved in a negative relationship (induced by an intimidating, competitive confederate). This result suggests that agents can represent self-generated and other-generated actions separately, but tend to relate or integrate these representations if the personal relationship between self and other has a positive valence.     

Improving self‐regulated learning of preschool children: Evaluation of training for kindergarten teachers

Background In the context of lifelong learning, self‐regulated learning is an important competence. Children between 4 and 6 years of age are at a crucial step in their life to develop self‐regulatory competence. That is why their kindergarten teachers play an important role as instructors as well as role models. Aim This study tested the effects of self‐regulation training for kindergarten teachers concerning their own self‐regulation and methods to foster self‐regulation in children at preschool age whom they were teaching. Sample In this study, 35 German kindergarten teachers and 97 children participated. All adult participants were graduated kindergarten teachers. Method The kindergarten teachers were tested with a questionnaire 2 weeks before and after the training. At the same time, the preschoolers were interviewed. A waiting control group design was applied. Results and conclusions The results obtained by means of analyses of variance show that the self‐regulation of the kindergarten teachers as well as the self‐regulated learning of preschoolers whose kindergarten teachers took part in the training improved significantly. The results indicate that it is possible to improve self‐regulated learning of preschool children by a training programme for kindergarten teachers.     

Common marmosets (<Emphasis Type="Italic">Callithrix jacchus</Emphasis>) do not utilize social information in three simultaneous social foraging tasks

Social foraging is suggested to increase foraging efficiency, as individuals might benefit from public information acquired by monitoring the foraging activities of other group members. We conducted a series experiments with captive common marmosets (Callithrix jacchus) to investigate to what extent marmosets utilize social information about food location when foraging simultaneously with conspecifics. Subjects were confronted with dominant and subordinate demonstrators in three experiments which differed in the amount of information about food location available to the demonstrators. In all three experiments, the focal subjects’ performance in the social condition was not enhanced in comparison to a non-social control condition. Because we could rule out kleptoparasitism and aggressive displacements as explanations, we argue that the subjects’ tendency for scramble competition by avoiding others and dispersing over the foraging area seems to inhibit or mask the acquisition of social information about the location of rewarded patches.     

Films for eliciting emotional states in children

Standardized sets of films have been shown to be effective for eliciting emotional states in adults, but no comparable validated stimuli are available for children. We therefore examined the effects of three pre-selected film clips each of 3-min duration in eliciting a pleasant, neutral and unpleasant emotional state in 297 children aged between 6 and 12 years. After the films were presented on a video projector, affective ratings were obtained with the Self-Assessment-Manikin on the emotional dimensions of valence and arousal. Increasing pleasure ratings were observed from the unpleasant to the neutral to the pleasant film. Associated arousal ratings were stronger for the unpleasant and pleasant films compared to the neutral film. Overall, results showed successful elicitation of targeted emotional states only marginally influenced by age, gender or prior experience with the films. The use of these films is therefore suggested for future studies on emotions in children.