A Computational Evaluation of Sentence Processing Deficits in Aphasia

Individuals with agrammatic Broca's aphasia experience difficulty when processing reversible non‐canonical sentences. Different accounts have been proposed to explain this phenomenon. The Trace Deletion account (Grodzinsky, 1995, 2000, 2006) attributes this deficit to an impairment in syntactic representations, whereas others (e.g., Caplan, Waters, Dede, Michaud, & Reddy, 2007; Haarmann, Just, & Carpenter, 1997) propose that the underlying structural representations are unimpaired, but sentence comprehension is affected by processing deficits, such as slow lexical activation, reduction in memory resources, slowed processing and/or intermittent deficiency, among others. We test the claims of two processing accounts, slowed processing and intermittent deficiency, and two versions of the Trace Deletion Hypothesis (TDH), in a computational framework for sentence processing (Lewis & Vasishth, 2005) implemented in ACT‐R (Anderson, Byrne, Douglass, Lebiere, & Qin, 2004). The assumption of slowed processing is operationalized as slow procedural memory, so that each processing action is performed slower than normal, and intermittent deficiency as extra noise in the procedural memory, so that the parsing steps are more noisy than normal. We operationalize the TDH as an absence of trace information in the parse tree. To test the predictions of the models implementing these theories, we use the data from a German sentence—picture matching study reported in Hanne, Sekerina, Vasishth, Burchert, and De Bleser (2011). The data consist of offline (sentence‐picture matching accuracies and response times) and online (eye fixation proportions) measures. From among the models considered, the model assuming that both slowed processing and intermittent deficiency are present emerges as the best model of sentence processing difficulty in aphasia. The modeling of individual differences suggests that, if we assume that patients have both slowed processing and intermittent deficiency, they have them in differing degrees.     

The mediational role of adolescents' friends in relations between activity breadth and adjustment

This investigation addresses the mediational role of friends' characteristics between adolescents' activity breadth (i.e., variety in activity participation) and their later adjustment. Data were drawn from 2 longitudinal studies: the Childhood and Beyond (CAB; N = 925) study and the Maryland Adolescent Development in Context Study (MADICS; N = 1,338). Adolescents at Time 2 in each study (8th, 9th, and 11th graders in CAB and 8th graders in MADICS) reported on the breadth of their participation across 5 activity settings: sports, religious, volunteering, community, and school. Friends' characteristics and adolescent adjustment were reported by adolescents at Times 1 and 3. Friends' positive characteristics significantly mediated relations between activity breadth and adolescent depressive affect, self-worth, alcohol use, and problem behavior in both studies. Friends' negative characteristics significantly mediated these relations in CAB, but not in MADICS.     

Rescuers and the Rescued

ABSTRACT: There is a fairly widespread but unverified belief that persons working on certain taboo areas may be similar to the population they serve and drawn to such work by their own personal problems in these areas. Two groups, 51 suicide prevention volunteers and 31 suicide attempters, were compared with respect to demographic characteristics and for psychological attitudes and experiences pertaining to suicide, death, and mental status by means of a death questionnaire developed by Shneidman. Comparative analysis revealed substantial differences between volunteers and clients. Demographically, the volunteers were older, better educated, more affluent, and contained a greater proportion of Protestants. Psychologically, the volunteers were distinctly different in regard to suicide. In contrast to their clients, the volunteers reported greater emotional stability, much less fantasy about suicide, almost no actual suicide attempts, and a disinclination to consider suicide as a justifiable problem-solving option.