Verbal and affective laterality effects in P-dyslexic, L-dyslexic and normal children.

Lateralization of verbal and affective processes was investigated in P-dyslexic, L-dyslexic and normal children with the aid of a dichotic listening task. The children were asked to detect either the presence of a specific target word or of words spoken in a specific emotional tone of voice. The number of correct responses and reaction time were recorded. For monitoring words, an overall right ear advantage was obtained. However, further tests showed no significant ear advantage for P-types, and a right ear advantage for L-types and controls. For emotions, an overall left ear advantage was obtained that was less robust than the word-effect. The results of the word task are in support of previous findings concerning differences between P- and L-dyslexics in verbal processing according to the balance model of dyslexia. However, dyslexic children do not differ from controls on processing of emotional prosody although certain task variables may have affected this result.     

Children’s incidental learning of the colors of objects and clothing

Few researchers have examined adults’ and children’s incidental recall of color information. In Experiment 1, we examined how well children recalled the colors of items seen in a first aid demonstration. Color recall of objects was above chance levels after three different time delays. However, recall of clothing color was poor. In Experiment 2, we examined whether colors of items from the same category (e.g., items of clothing) were more difficult to remember than distinct items (i.e., belonging to a range of different categories). Children and adults saw 18 items from three different categories. Color recall was above chance levels. The colors of distinct items were recalled more often than the color of category items. The results suggest that color is encoded automatically to some extent. However, participants had difficulty in recalling the color of clothing worn by the experimenter.     

Developing algorithms to enhance the sensitivity of cancellation tests of visuospatial neglect

We describe a set of algorithms that enhance the sensitivity of cancellation tests used in assessing visuospatial neglect. The algorithms can be readily implemented on a computer and can provide temporal and nontemporal data on strategies used during cancellation. We also present preliminary results from a group of 68 right-hemisphere brain-damaged patients and 12 age-matched control participants, which demonstrate the clinical significance of the measures we have defined.     

The paradox of negation in Nāgārjuna's philosophy

This essay discusses the paradox of the Nāgārjunian negation as presented in his Vigrahavyāvartani. In Part One it is argued that as the Naiyāyika remarks, Nāgārjuna's speech act ‘No proposition has its own intrinsic thesis’ seemingly contradicts his famous claim that he has no negation whatsoever. In Parts Two and Three I consider the traditional as well as modem responses to this paradox and offer my own. I argue that Nāgārjuna's speech act does not generate a paradox for two reasons: (a) the equivalence thesis of the kind‐?P = ?P is obviously false; and (b) since Nāgārjuna's speech act is situated in the dialogical/conversational universe of discourse as opposed to the argumentative/systematic universe of discourse, the teaching of the non‐intrinsic thesis of all statements that it purports, holds for all statements in its class, including itself. Lastly, it is argued that even though the Nāgārjunian speech act is not a negation situated in the argumentative universe of discourse, it serves both philosophical and soteriological purposes.     

Investigating the influence of an effort–reward interaction on cognitive fatigue in individuals with multiple sclerosis

This study examined whether an alteration in the effort–reward relationship, a theoretical framework based on cognitive neuroscience, could explain cognitive fatigue. Forty persons with MS and 40 healthy age- and education-matched cognitively healthy controls (HC) participated in a computerized switching task with orthogonal high- and low-demand (effort) and reward manipulations. We used the Visual Analog Scale of Fatigue (VAS-F) to assess subjective state fatigue before and after each condition during the task. We used mixed-effects models to estimate the association and interaction between effort and reward and their relationship to subjective fatigue and task performance. We found the high-demand condition was associated with increased VAS-F scores (p < .001), longer response times (RT) (p < .001) and lower accuracy (p < .001). The high-reward condition was associated with faster RT (p = .006) and higher accuracy (p = .03). There was no interaction effect between effort and reward on VAS-F scores or performance. Participants with MS reported higher VAS-F scores (p = .02). Across all conditions, participants with MS were slower (p < .001) and slower as a function of condition demand compared with HC (p < .001). This behavioural study did not find evidence that an effort–reward interaction is associated with cognitive fatigue. However, our findings support the role of effort in subjective cognitive fatigue and both effort and reward on task performance. In future studies, more salient reward manipulations could be necessary to identify effort–reward interactions on subjective cognitive fatigue.     

Olfactory discrimination learning in mice lacking the fragile X mental retardation protein

An automated training system was used to compare the behavior of knockout (KO) mice lacking the fragile X mental retardation protein with that of wild-type (WT) mice (C57Bl/6 strain) in the acquisition and retention of olfactory discriminations. KO and WT mice did not differ in the acquisition of a four-stage nose poke shaping procedure. In two separate experiments, mutant mice required substantially more training to acquire a series of novel olfactory discrimination problems than did control mice. The KO mice required significantly more sessions to reach criterion performance, made significantly more errors during training, and more often failed to acquire discriminations. Both KO and WT mice showed similar error patterns when learning novel discriminations and both groups showed evidence of more rapid learning of later discriminations in the problem series. Both groups showed significant long-term memory two or four weeks after training but WT and KO mice did not differ in this regard. A group of well-trained mice were given training on novel odors in sessions limited to 20–80 trials. Memory of these problems at two day delays did not differ between WT and KO mice. Tests using ethyl acetate demonstrated that WT and KO mice had similar odor detection thresholds.     

Incentivizing physical activity using token reinforcement with preschool children

We combined several single‐subject designs to assess the effects of contingent and noncontingent token reinforcement on moderate‐to‐vigorous physical activity (MVPA) exhibited by 4 preschool‐aged children. Higher overall levels and longer bouts of MVPA reliably occurred when tokens were delivered contingent on MVPA for 3 of the 4 children when compared to baseline (no token) and for 2 of the 4 children when compared to noncontingent‐token conditions. The present study demonstrated that the delivery of tokens contingent on MVPA can increase and maintain MVPA exhibited by preschool‐aged children, resulting in more MVPA than in baseline conditions and conditions in which tokens are awarded without respect to MVPA. These results demonstrate that token economies can be used to increase MVPA and they add to the evidence base supporting the use of token economies to address a range of behavior problems.     

Intrusive images and memories in major depression

Individuals with current major depression were interviewed to investigate the prevalence of distressing intrusive mental imagery among depressed patients and study the phenomenology of these intrusions. Of the 39 currently depressed patients, 17 experienced some form of repetitive intrusive imagery (i.e., either an intrusive memory or image), with intrusive memories being more common than images. The intrusive imagery was experienced as highly uncontrollable and interfered significantly with patients' everyday lives. The intrusions were experienced with a sense of 'nowness', as well as physical and emotional re-experiencing. Despite high levels of re-experiencing, levels of dissociation were very low. The intrusive imagery was in some patients part of a wider network of key defining autobiographical memories, consistent with the idea that it is likely to play a significant role in maintaining the patient's depressive mood. Interventions targeting these intrusions could potentially result in a positive shift in depressed mood.     

On the relative contributions of noncontingent reinforcement and escape extinction in the treatment of food refusal

In the current investigation, we evaluated the relative effects of noncontingent reinforcement (NCR), escape extinction, and a combination of NCR and escape extinction as treatment for the feeding problems exhibited by 4 children. For each participant, consumption increased only when escape extinction was implemented, independent of whether NCR was present or absent. These results were consistent with prior research suggesting that positive reinforcement alone is insufficient for increasing consumption, and that escape extinction often is necessary to increase and maintain food acceptance. However, NCR appeared to decrease inappropriate behavior for some participants.