Cognitive processes that underlie mathematical precociousness in young children

The working memory (WM) processes that underlie young children's (ages 6-8 years) mathematical precociousness were examined. A battery of tests that assessed components of WM (phonological loop, visual-spatial sketch pad, and central executive), naming speed, random generation, and fluency was administered to mathematically precocious and average-achieving children. The results showed that (a) precocious children performed better on executive processing, inhibition, and naming speed tasks than did average-achieving children, although the two groups were statistically comparable on measures of the phonological loop and visual-spatial sketch pad, and (b) the executive component of WM predicted mathematical accuracy independent of chronological age, reading, inhibition, and naming speed. The results support the notion that the executive system is an important predictor of children's mathematical precociousness and that this system can operate independent of individual differences in the phonological loop, inhibition, and reading in predicting mathematical accuracy.     

The differential effects of thalamus and basal ganglia on facial emotion recognition

This study examined if subcortical stroke was associated with impaired facial emotion recognition. Furthermore, the lateralization of the impairment and the differential profiles of facial emotion recognition deficits with localized thalamic or basal ganglia damage were also studied. Thirty-eight patients with subcortical strokes and 19 matched normal controls volunteered to participate. The participants were individually presented with morphed photographs of facial emotion expressions over multiple trials. They were requested to classify each of these morphed photographs according to Ekman's six basic emotion categories. The findings indicated that the clinical participants had impaired facial emotion recognition, though no clear lateralization pattern of impairment was observed. The patients with localized thalamic damage performed significantly worse in recognizing sadness than the controls. Longitudinal studies on patients with subcortical brain damage should be conducted to examine how cognitive reorganization post-stroke would affect emotion recognition.     

Reorientation and landmark-guided search by young children: evidence for two systems

Disoriented 4-year-old children use a distinctive container to locate a hidden object, but do they reorient by this information? We addressed this question by testing children's search for objects in a circular room containing one distinctive and two identical containers. Children's search patterns provided evidence that the distinctive container served as a direct cue to a hidden object's location, but not as a directional signal guiding reorientation. The findings suggest that disoriented children's search behavior depends on two distinct processes: a modular reorientation process attuned to the geometry of the surface layout and an associative process linking landmarks to specific locations.     

Exposure to disgust-evoking imagery and information processing biases in blood-injection-injury phobia

Biased processing of threat-relevant information is a central construct among contemporary theories of anxiety. However, biases in attentional and memory processes have not been systematically investigated in blood-injection-injury (BII) phobia. Theory has suggested that disgust rather than fear characterizes BII phobia and may mediate processing biases differently. We investigated the effects of a disgust mood induction on attention and memory in BII phobic and nonphobic participants. The Stroop task failed to demonstrate an attentional bias toward medical and disgust words, even under conditions of disgust provocation. However, an implicit memory task showed that BII phobics completed more medical and disgust word stems than nonphobics. These results suggest that BII phobia may be characterized by a similar implicit memory, but not an attentional, bias found in other anxiety disorders. As such, information processing in BII phobia may be qualitatively different from other anxiety disorders. Implications for further research regarding information processing biases in BII phobia are discussed.     

Attentional resource and processing speed limitations during sentence processing in Parkinson's disease

Several studies have suggested that patients with Parkinson's disease (PD) have sentence comprehension difficulty in part because of their limited executive resources. However, these assessments confound the executive resources contributing to sentence comprehension with the resources needed for task performance. In the present study, we used a word detection technique that minimizes task demands in order to evaluate attentional and processing speed resources during the comprehension of simple sentences without subordinate clauses and sentences containing subject-relative and object-relative center-embedded subordinate clauses. We found that PD patients have poor sensitivity to phonetic errors embedded in unbound grammatical morphemes, regardless of the clausal structure of the sentence, suggesting difficulty attending to grammatical morphemes. We also found that PD patients are significantly slowed in their sensitivity to phonetic errors in content words embedded in object-relative center-embedded sentences. Slowed sensitivity to content words in object-relative sentences was correlated with timed executive measures of planning. On a traditional measure of comprehension, these PD patients were impaired for sentences containing object-relative center-embedded clauses compared to sentences with subject-relative center-embedded clauses, and comprehension of object-relative sentences was correlated with executive measures. Our findings are consistent with the claim that limited executive resources for strategic attention and processing speed contribute to the sentence comprehension difficulties of PD patients.     

Silent letters and phonological priming

Many written English words contain silent letters. Omitting them produces nonwords pronounced identically to the original words, for example, SALM for PSALM and COLUM for COLUMN. We report two naming and two lexical decision experiments in which targets of 4–11 letters followed primes exposed for 100 ms in mask-prime-mask-target sequences. Priming in SALM-psalm and COLUM-column pairs exceeded priming in orthographic control pairs such as ASTA-pasta and COUSI-cousin, pairs in which pronounced letters are omitted to form the primes. SALM and COLUM, however, were less effective primes than PSALM and COLUMN. Results were discussed in terms of the phonological coherence hypothesis, the role of orthographic codes in filtering phonologically activated representations, and graphemes as reading units.     

Dissociations among functional categories in Korean agrammatism

This study investigated the hypothesis that the syntactic trees formed by individuals with agrammatic aphasia cannot be constructed any higher than an impaired node as suggested by the tree-pruning hypothesis (Friedman, 1994; Friedmann & Grodzinsky, 1997) and hypothesis. It also examined their following implication that the members of a certain functional category are subject to the same degree of impairment. Two experiments were conducted to investigate a Korean agrammatic patient's use and understanding of three functional categories--Mood, Tense, and Complementizer. The results showed a dissociation among functional categories that preserves the higher node while leaving the lower node impaired both in production and comprehension. Another dissociation was found among members of the same category depending on their linear position in the clause. These results contrast with the predictions of the tree-pruning hypothesis, suggesting that the nearer to the end of the clause a functional element is located, the better it is preserved in Korean agrammatism.