Modeling individual differences in working memory performance: a source activation account

Working memory resources are needed for processing and maintenance of information during cognitive tasks. Many models have been developed to capture the effects of limited working memory resources on performance. However, most of these models do not account for the finding that different individuals show different sensitivities to working memory demands, and none of the models predicts individual subjects' patterns of performance. We propose a computational model that accounts for differences in working memory capacity in terms of a quantity called source activation , which is used to maintain goal-relevant information in an available state. We apply this model to capture the working memory effects of individual subjects at a fine level of detail across two experiments. This, we argue, strengthens the interpretation of source activation as working memory capacity.     

Deep dyslexia in the two languages of an Arabic/French bilingual patient.

We present a single case study of an Arabic/French bilingual patient, ZT, who, at the age of 32, suffered a cerebral vascular accident that resulted in a massive infarct in the left peri-sylvian region. ZT's reading displays the characteristics of the deep dyslexia syndrome in both languages, that is, production of semantic, visual, and morphological errors, and concreteness effect in reading aloud and impossibility of reading nonwords. In the first part of this paper, using a three-route model of reading, we account for the patient's performance by positing functional lesions, which affect the non-lexical, the semantic lexical and the non-semantic lexical routes of reading. Phonological priming observed in a cross-language visual lexical decision task indicates that implicit assembled phonological recoding is possible. The above lesions and implicit nonword reading characterize the output form of deep dyslexia. However, error distribution reveals dissociations across languages (e.g. the semantic error rate is higher in French whereas translations are more frequent in the Arabic testing) that cannot be accounted for within a three-route model. In the second part, extensions to Plaut and Shallice's connectionist model (Cognitive Neuropsychology, 10 (5) (1993) 377) are proposed to account for the translinguistic errors observed. ZT's error distribution is compared to that obtained by Plaut and Shallice after lesions had been applied at different locations through the 40-60 network. The overall syndrome of deep dyslexia found in both languages is explained as resulting from lesions along the direct (O-->I) and output (S-->Ip, Ip-->P) pathways of reading. Lesions along the output pathway mostly affecting S-->Ip connections in French and Ip-->P connections in Arabic account for discrepancies in ZT's error pattern across tasks and languages. This case study demonstrates the superiority of a connectionist approach for predicting the error pattern in deep dyslexia.     

Tolerant (In)civility? A Longitudinal Analysis of White Conservative Protestants’ Willingness to Grant Civil Liberties

Past research has found conservative Protestants to be less willing than most Americans to grant civil liberties to unpopular groups. In light of evidence of high and growing civility by Smith (2000) and Hunter (1984), there is good reason to believe that conservative Protestants are becoming less distinctive with regard to granting civil freedoms. We update and expand previous research on conservative Protestants and civil liberties by examining the civil liberties measures in the General Social Survey over a 26-year period, with special attention to explaining conservative Protestantism's rejection of civil liberties. In comparison to mainline Protestants and Catholics, we find that conservative Protestants are still less willing to grant civil liberties to unpopular groups, though important qualifications apply. Various explanations are examined.     

Psychological factors and depressive symptoms in ischemic heart disease.

The aim of this study was to determine whether learned helplessness, cognitive distortions, self-efficacy, and dispositional optimism assessed at Time 1 (T1; questionnaires mailed at 1 month postdischarge) would predict depressive symptoms at Time 2 (T2; questionnaires mailed at 1-year follow-up) in a sample of 86 patients hospitalized with ischemic heart disease. Multiple regression results indicated that optimism and cognitive distortions at T1 were significantly associated with T1 depressive symptoms after controlling for confounding variables. When the T1 psychological factors were analyzed with T2 depressive symptoms, only optimism continued to predict depressive symptoms after controlling for confounds and T1 depressive symptoms. The global expectancies that optimism assessed appeared to be more stable over time than the statelike beliefs of cognitive distortions and may have accounted for why optimism predicted T2 depressive symptoms.