The time course of competition for attention: attention is initially labile

Competition for attention between 2 written words was investigated by presenting the words briefly in a single stream of distractors (Experiment 1) or in different streams (Experiment 2-6), using rapid serial visual presentation at 53 ms/item. Stimulus onset asynchrony (SOA) was varied from 0 to 213 ms. At all SOAs there was strong competition, but which word was more likely to be reported shifted markedly with SOA. At SOAs in the range of 13-53 ms the second word was more likely to be reported, but at 213 ms, the advantage switched to the first word, as in the attentional blink. A 2-stage competition model of attention is proposed in which attention to a detected target is labile in Stage 1. Stage 1 ends when one target is identified, initiating a serial Stage 2 process of consolidation of that target.     

Effect of speech task on intelligibility in dysarthria: a case study of Parkinson's disease

This study assessed intelligibility in a dysarthric patient with Parkinson's disease (PD) across five speech production tasks: spontaneous speech, repetition, reading, repeated singing, and spontaneous singing, using the same phrases for all but spontaneous singing. The results show that this speaker was significantly less intelligible when speaking spontaneously than in the other tasks. Acoustic analysis suggested that relative intensity and word duration were not independently linked to intelligibility, but dysfluencies (from perceptual analysis) and articulatory/resonance patterns (from acoustic records) were related to intelligibility in predictable ways. These data indicate that speech production task may be an important variable to consider during the evaluation of dysarthria. As speech production efficiency was found to vary with task in a patient with Parkinson's disease, these results can be related to recent models of basal ganglia function in motor performance.     

Synesthetic color experiences influence memory

We describe the extraordinary memory of C, a 21–year–old student who experiences synesthetic colors (i.e., photisms) when she sees, hears, or thinks of digits. Using three matrices of 50 digits, we tested C and 7 nonsynesthetes to evaluate whether C's synesthetic photisms influence her memory for digits. One matrix consisted of black digits, whereas the other two matrices consisted of digits that were either incongruent or congruent with the colors of C's photisms. C's recall of the incongruently colored digits was considerably poorer than her recall of either the black or the congruently colored digits. The 7 nonsynesthetes did not show such differences in their recall of the matrices. In addition, when immediate recall of the black digits was compared with delayed recall of those digits (48 hr), C showed no decrease in performance, whereas each of the nonsynesthetes showed a significant decrease. These findings both demonstrate C's extraordinary memory and show that her synesthetic photisms can influence her memory for digits.     

Psychopathy screening of incarcerated juveniles: a comparison of measures

How well do brief screening measures correspond with a full-scale assessment of psychopathy among juvenile offenders? This study compared 3 independent screening measures (the Antisocial Process Screening Device [APSD] Self-Report [A. A. Caputo, P. J. Frick, & S. L. Brodsky, 1999], the APSD Staff Rating [P. J. Frick & R. D. Hare, 2001], and the Psychopathy Content Scale [D. C. Murrie & D. G. Cornell, 2000] on the Millon Adolescent Clinical Inventory [T. Millon, 1993]) with the Psychopathy Checklist: Youth Version (PCL:YV; A. E. Forth, D. S. Kosson, & R. D. Hare, in press) in a sample of 117 incarcerated male juveniles. Modest correlations (.30-.49) were found between PCL:YV scores and those of the 3 screening measures, and there was moderate accuracy (67%-82%) in identifying youth who scored relatively high (> or = 25) on the PCL:YV. Although these results support the construct of adolescent psychopathy, they indicate substantial limitations in the use of psychopathy screening measures with juvenile offenders.     

Evidence for preserved representations in change blindness

People often fail to detect large changes to scenes, provided that the changes occur during a visual disruption. This phenomenon, known as "change blindness," occurs both in the laboratory and in real-world situations in which changes occur unexpectedly. The pervasiveness of the inability to detect changes is consistent with the theoretical notion that we internally represent relatively little information from our visual world from one glance at a scene to the next. However, evidence for change blindness does not necessarily imply the absence of such a representation---people could also miss changes if they fail to compare an existing representation of the pre-change scene to the post-change scene. In three experiments, we show that people often do have a representation of some aspects of the pre-change scene even when they fail to report the change. And, in fact, they appear to "discover" this memory and can explicitly report details of a changed object in response to probing questions. The results of these real-world change detection studies are discussed in the context of broader claims about change blindness.     

Extending the ALCOVE model of category learning to featural stimulus domains

The ALCOVE model of category learning, despite its considerable success in accounting for human performance across a wide range of empirical tasks, is limited by its reliance on spatial stimulus representations. Some stimulus domains are better suited to featural representation, characterizing stimuli in terms of the presence or absence of discrete features, rather than as points in a multidimensional space. We report on empirical data measuring human categorization performance across a featural stimulus domain and show that ALCOVE is unable to capture fundamental qualitative aspects of this performance. In response, a featural version of the ALCOVE model is developed, replacing the spatial stimulus representations that are usually generated by multidimensional scaling with featural representations generated by additive clustering. We demonstrate that this featural version of ALCOVE is able to capture human performance where the spatial model failed, explaining the difference in terms of the contrasting representational assumptions made by the two approaches. Finally, we discuss ways in which the ALCOVE categorization model might be extended further to use “hybrid” representational structures combining spatial and featural components.     

Cholinesterase-inhibitor therapy for dementia: novel clinical substrates and mechanisms for treatment response

Historically, drugs that increase central cholinergic transmission have primarily been investigated for relieving cognitive symptoms in mild-to-moderate Alzheimer's disease. These efforts have led to the somewhat unexpected findings that cholinergic therapy has a beneficial effect on selected neuropsychiatric symptoms in AD across disease stages. In Parkinson's disease with dementia and dementia with Lewy bodies, cholinergic deficits are more severe than in AD, and there is emerging evidence that cholinesterase inhibitors are efficacious in treating core symptoms of attentional disturbance and psychosis. Recent data also suggest a rational basis for cholinergic therapy in vascular dementia. The cognitive and neuropsychiatric effects of cholinergic therapy observed in AD and other dementias form the crux of an integrative model of cholinergic therapeutic efficacy that encompasses the diverse central nervous system actions of acetylcholine and its complementary interactions with central monoamine transmitters. This heuristic framework highlights the broader therapeutic potential of cholinergic therapy for symptom-based indications in other neuropsychiatric disorders.     

Notes on Contributors

Biography

Notes on Contributors     

Touching Mortality, Touching Strength: Clinical Work with Dying Patients

This paper outlines some of the special stresses that must be shouldered by clinicians—physicians, nurses, chaplains, social workers, pastoral staff, and others—whose work focuses on dying and extremely vulnerable patients. The utility of a theory of generative death anxiety as a framework for interpreting the nature of these special stresses is suggested. Three common burnout reactions are examined. The paper concludes that positive acceptance of personal mortality may help clinicians avoid burnout and lead to better therapeutic practice. This framework for interpreting therapeutic practice demonstrates the integral role spirituality plays in work with this particular patient group.