Resistance to extinction as a function of percentage of reward: A reinforcement-level interpretation

Three experiments investigated the effects of percentage of reinforcement on the resistance to extinction of an instrumental running response. In Experiment 1, with N-length held constant, 47% reinforcement during acquisition generated greater resistance to extinction (R_n) than did 77%. In Experiment 2, this result was replicated with both functional N-length and number of N-R transitions held constant. In Experiment 3, R_n was shown to be a function of both N-length and percentage of reinforcement. The results of all three experiments were discussed in terms of Capaldi’s reinforcement level theory and possible alternative explanations.     

Target-defining features in a “people-present/people-absent” discrimination task by pigeons

Aust and Huber (2001) demonstrated that in apeople-present/people-absentdiscrimination task, pigeons actually attended to properties of the target (i.e., the human figure). The aim of the present effort was to specify what sort of information contained in the target was used for classification, as well as to investigate whether and in what way the target-defining features interacted. Six pigeons were trained in a go/no-go procedure to discriminate between color photographs characterized by the presence or absence of people. They were then presented with various types of test stimuli that contained some category-relevant features but lacked others. The results showed that properties related to target size and internal structure played an important role and that human silhouettes were insufficient for eliciting a people-present response. Furthermore, some properties of the human figure (e.g., hands/arms) made good predictors of the people-present category, whereas others (e.g., feet/legs or skin color) did not. Responses to test stimuli that belonged to the people-absent category but nevertheless contained some features normally typical for humans (e.g., nonhuman primates) provided evidence that various category-relevant features contributed to classification in an additive way. Taken together, the results suggest that the pigeons made use of a polymorphous class rule involving collections of differently weighted target features.     

Elemental versus configural perception in a people-present/people-absent discrimination task by pigeons

In the present experiment, we investigated whether pigeons rely exclusively on elemental information or whether they are also able to exploit configural information in apeople-present/people-absent discrimination task. Six pigeons were trained in a go/no-go procedure to discriminate between 800 color photographs characterized by the presence or absence of people. Thepeople-present stimuli were designated as positive, and thepeople-absent stimuli were designated as negative. After training and a subsequent generalization test, the pigeons were presented with both familiar and novel people-present stimuli containing human figures that were distorted in one of seven different ways. All the pigeons learned the initial discrimination and also showed generalization to novel stimuli. In the subsequent test, performance on all types of distorted stimuli was diminished in comparison with that on the intact original pictures from which they had been derived. At the same time, however, peck rates clearly exceeded the level of responding found for regular people-absent stimuli. This result strongly suggests that responding was controlled by both the constituting target components and their spatial relations and, therefore, points to the dual importance of elemental and configural information.     

Genetics and Neuroscience in Dyslexia: Perspectives for Education and Remediation

ABSTRACT— Our understanding of the causes of a developmental disorder like dyslexia has received recent input from both neuroscience and genetics. The discovery of 4 candidate genes for dyslexia and the identification of neuronal networks engaged when children read and spell are the basis for introducing this knowledge into education. However, the input from educational practitioners as well as empirical knowledge from research on learning also contribute significantly to our understanding of how children acquire the basic skills for learning to read and spell. It is imperative to merge the knowledge acquired from research in the fields of neuroscience, genetics, and empirical education, as well as to understand how the learning brain and instruction interact. Doing so can be seen as a major step in attaining an optimal approach for teaching, reading, and spelling and for finding the best suited and most effective treatment concepts for dyslexic children and adolescents.     

Expansion and effectiveness of private tutoring

Private paid tutoring is one of the most common approaches of remedial instruction to improve school performance of poorly performing pupils. The expansion of private tutoring was affirmed in a study with 904 pupils in Luxembourg. 23% of the participants reported that they receive tutoring at present, mainly in the subject matter of Mathematics. Theoretical considerations suggest the effectiveness of private tutoring in promoting school performance by an improvement in cognitive and motivational variables and a higher amount of time spent on task. However, appropriate evaluation studies are lacking. In an empirical study the effectiveness of tutoring is evaluated in a prepost-control-group-design. One group (N=122) received private tutoring over a period of nine months and was compared to a non-tutoring control group (N=122). These results indicate that receiving tutoring leads to a larger improvement in school performance and motivational variables. Directions for further research and practical implications are discussed.     

Hemoglobin Hasharon and hemoglobin NYU in subjects of German origin

Determination of HbA1c values with high performance liquid chromatography (HPLC) occasionally reveals hemoglobin anomalies with no or minimal clinical evidence. We coincidentally detected two cases of Hb Hasharon, an alpha globin gene mutation, in two heterozygous patients and one case of Hb NYU, a delta globin gene mutation, in another patient. Both anomalies have not been described in subjects of German origin to date. Characterization was carried out with HPLC, hemoglobin electrophoresis, capillary zone electrophoresis, DNA sequencing, complete blood count and clinical chemical analysis.     

Psychological Benefits of Participation in Three-dimensional Virtual Worlds for Individuals with Real-world Disabilities

One hundred and ninety-six individuals with real-world disabilities were administered a battery of psychological adjustment measures soon after joining the three-dimensional virtual world of Second Life^®. After three months, 61 participants who continued to be actively involved in Second Life were re-administered the adjustment measures and completed a survey about their virtual and real-life experiences during the interval between assessments. Participants’ scores significantly improved on measures of affective states (depression, anxiety, positive emotion, life satisfaction, and feelings of loneliness) and self-evaluation (self-esteem). An index of overall change was associated with the number of virtual friends and group affiliations in Second Life, as well as feelings about the self as a result of involvement in the virtual world. The current study provides initial empirical support that three-dimensional virtual worlds can serve as a psychologically beneficial context for individuals with real-life disabilities.     

Learning from pictorial analogies

The use of visualisation in learning material is increasing rapidly. Three major categories of pictures or illustrations are distinguished: representational pictures, logical pictures, and pictorial analogies. This article concentrates on pictorial analogies of which the cognitive functioning depends on identical relations between two non-identical domains. To get more insight into the crucial parameters of pictorial analogies in combination with expository text, two investigatory studies with physics materials are reported. The results show that the use of pictorial analogies can improve learning significantly if they are designed properly and used together with the expository text to be studied. Pictorial analogies should be carefully developed in regard to high structural similarity between the base and the target domain. Understanding of the analogical relationship is supported by inter-connecting the information text closely with references to the relevant features of the pictorial analogy.     

The role of item- and category-specific information in the discrimination of people versus nonpeople images by pigeons

Herrnstein and Loveland (1964, pp. 549–551) successfully trained pigeons to discriminate pictures showing humans from pictures that did not. In the present study, a go/no-go procedure was employed to replicate and extend their findings, the primary focus of concern being to reevaluate the role of item- and category-specific information. The pigeons readily acquired the discrimination and were also able to generalize to novel instances of the two classes (Experiment 1). Classification of scrambled versions of the stimuli was based on small and local features, rather than on configural and global features (Experiment 2). The presentation of gray-scale stimuli indicated that color was important for classifying novel stimuli and recognizing familiar ones (Experiments 1 and 2). Finally, the control that could possibly be exerted by irrelevant background features was investigated by presenting the pigeons with images of persons contained in former person-absent pictures (Experiment 3). Classification was found to be controlled by both item- and category- specific features, but only in pigeons that were reinforced on person-present pictures was the latter type of information given precedence over the former.