The Relevance of a Relevantly Assertable Disjunction for Material Implication

In this paper Grice’s requirements for assertability are imposed on the disjunction of Classical Logic. Defining material implication in terms of negation and disjunction supplemented by assertability conditions, results in the disappearance of the most important paradoxes of material implication. The resulting consequence relation displays a very strong resemblance to Schurz’s conclusion-relevant consequence relation.     

The time course of location-avoidance learning in fear of spiders

Two experiments were designed to study the time course of avoidance learning in spider fearfuls (SFs) under controlled experimental conditions. To achieve this, we employed an immersive virtual environment (IVE): While walking freely through a virtual art museum to search for specific paintings, the participants were exposed to virtual spiders. Unbeknown to the participants, only two of four museum rooms contained spiders, allowing for avoidance learning. Indeed, the more SF the participants were, the faster they learned to avoid the rooms that contained spiders (Experiment. 1), and within the first six trials, high fearfuls already developed a preference for starting their search task in rooms without spiders (Experiment 2). These results illustrate the time course of avoidance learning in SFs, and they speak to the usefulness of IVEs in fundamental anxiety research.     

Interactions between working memory and language in young children with specific language impairment (SLI)

The underlying structure of working memory (WM) in young children with and without specific language impairment (SLI) was examined. The associations between the components of WM and the language abilities of young children with SLI were then analyzed. The Automated Working Memory Assessment and four linguistic tasks were administered to 58 children with SLI and 58 children without SLI, aged 4–5 years. The WM of the children was best represented by a model with four separate but interacting components of verbal storage, visuospatial storage, verbal central executive (CE), and visuospatial CE. The associations between the four components of WM did not differ significantly for the two groups of children. However, the individual components of WM showed varying associations with the language abilities of the children with SLI. The verbal CE component of WM was moderately to strongly associated with all the language abilities in children with SLI: receptive vocabulary, expressive vocabulary, verbal comprehension, and syntactic development. These results show verbal CE to be involved in a wide range of linguistic skills; the limited ability of young children with SLI to simultaneously store and process verbal information may constrain their acquisition of linguistic skills. Attention should thus be paid to the language problems of children with SLI, but also to the WM impairments that can contribute to their language problems.     

Haptic object matching by blind and sighted adults and children

The present study describes a tactual object matching task based on the study of Lederman and Klatzky (1987) for the dimensions Exact shape, Weight, Volume and Texture. Participants were congenitally blind children and their sighted classmates, congenitally blind adults and sighted adults. To study a possible effect of familiarity the task was performed four times. Based on Millar's CAPIN (Convergent Active Processes in Interrelated Networks) model of spatial processing (Millar, 1994) it was thought that this manipulation would add redundant information to the experiment from which the children and blind participants could benefit. The results showed that accuracy was affected more by age than visual status, especially for the dimension Exact Shape. With regard to response times, children were in most cases faster than adults, especially the sighted adults. Familiarization had a significant effect on response times for all dimensions. Extra exercise only increased accuracy for the dimension Texture. These results were generally in line with the CAPIN model.     

Social-emotional characteristics of gifted accelerated and non-accelerated students in the Netherlands

Background. In the studies of acceleration conducted so far a multidimensional perspective has largely been neglected. No attempt has been made to relate social-emotional characteristics of accelerated versus non-accelerated students in perspective of environmental factors. Aims. In this study, social-emotional characteristics of accelerated gifted students in the Netherlands were examined in relation to personal and environmental factors. Samples. Self-concept and social contacts of accelerated (n = 148) and non-accelerated (n = 55) gifted students, aged 4 to 27 (M = 11.22, SD = 4.27) were measured. Method. Self-concept and social contacts of accelerated and non-accelerated gifted students were measured using a questionnaire and a diary, and parents of these students evaluated their behavioural characteristics. Gender and birth order were studied as personal factors and grade, classroom, teachers’ gender, teaching experience, and the quality of parent-school contact as environmental factors. Results. The results showed minimal differences in the social-emotional characteristics of accelerated and non-accelerated gifted students. The few differences we found favoured the accelerated students. We also found that multiple grade skipping does not have negative effects on social-emotional characteristics, and that long-term effects of acceleration tend to be positive. As regards the possible modulation of personal and environmental factors, we merely found an impact of such factors in the non-accelerated group. Conclusions. The results of this study strongly suggest that social-emotional characteristics of accelerated gifted students and non-accelerated gifted students are largely similar. These results thus do not support worries expressed by teachers about the acceleration of gifted students. Our findings parallel the outcomes of earlier studies in the United States and Germany in that we observed that acceleration does not harm gifted students, not even in the case of multiple grade skipping. On the contrary, there is a suggestion in the data that accelerated students are more socially competent than non-accelerated students. The findings in this study can reassure those parents and teachers who worry about the social-emotional consequences of acceleration in school: If a student is gifted, acceleration seems to be a sound and, in many cases, appropriate measure in gifted education.     

Do testing effects change over time? Insights from immediate and delayed retrieval speed

Retrieving information from memory improves recall accuracy more than continued studying, but this testing effect often only becomes visible over time. In contrast, the present study documents testing effects on recall speed both immediately after practice and after a delay. A total of 40 participants learned the translation of 100 Swahili words and then further restudied the words with translations or retrieved the translations from memory during testing. As in previous experiments, recall accuracy was higher for restudied words than for tested words immediately after practice, but higher for tested words after 7 days. Response times for correct answers, however, showed a different result: Learners were faster to recall tested words than restudied words both immediately after practice and after 7 days. These results are interpreted in light of recent suggestions that testing selectively strengthens cue–response associations. An additional outcome was that testing effects on recall accuracy were related to perceived retrieval success during practice. When several practice retrievals were successful, testing effects on recall accuracy were already significant immediately after practice. Together with the reaction time data, this supports recent models that attribute changes in testing effects over time to limited item retrievability during practice.