Lexical processes and eye movements in neglect dyslexia

Neglect dyslexia is a disturbance in the allocation of spatial attention over a letter string following unilateral brain damage. Patients with this condition may fail to read letters on the contralesional side of an orthographic string. In some of these cases, reading is better with words than with non-words. This word superiority effect has received a variety of explanations that differ, among other things, with regard to the spatial distribution of attention across the letter string during reading. The primary goal of the present study was to explore the interaction between attention and lexical processes by recording eye movements in a patient (F.C.) with severe left neglect dyslexia who was required to read isolated word and non-word stimuli of various length. F.C.'s ocular exploration of orthographic stimuli was highly sensitive to the lexical status of the letter string. We found that: (1) the location to which F.C. directed his initial saccade (obtained approximately 230 ms post-stimulus onset) differed between word and non-word stimuli; (2) the patient spent a greater amount of time fixating the contralesional side of word than non-word strings. Moreover, we also found that F.C. failed to identify the left letters of a string despite having fixated them, thus showing a clear dissociation between eye movement responses and conscious access to orthographic stimuli. Our data suggest the existence of multiple interactions between lexical, attentional and eye movement systems that occur from very initial stages of visual word recognition.     

Medical ethics in an era of bioethics: Resetting the medical profession’s compass

What it means to be a medical professional has been defined by medical ethicists throughout history and remains a contemporary concern addressed by this paper. A medical professional is generally considered to be one who makes a public promise to fulfill the ethical obligations expressed in the Hippocratic Code. This presentation summarizes the history of medical professionalism and refocuses attention on the interpersonal relationship of doctor and patient. This keynote address was delivered at the Founders of Bioethics International Congress (June, 2010).     

Allocation of resources at the bedside: the intersections of economics, law, and ethics

In the preceding article, Mehlman and Massey examine possible legal responses to the issues that confront physicians faced with treating patients who have insufficient financial resources. This commentary explores the same issues from the perspective of ethics, including a comparison of the way law and ethics interpret the physician-patient relationship, the ethical obligations of physicians that are inherent in that relationship, and the propriety of Mehlman and Massey's legal and ethical proposals to ameliorate physicians' conflicting obligations in providing or withholding care on grounds of conservation of society's resources.     

Short-term retention of pictures and words: evidence for dual coding systems.

The recall of picture and word triads was examined in three experiments that manipulated the type of distraction in a Brown-Peterson short-term retention task. In all three experiments recall of pictures was superior to words under auditory distraction conditions. Visual distraction produced high performance levels with both types of stimuli, whereas combined auditory and visual distraction significantly reduced picture recall without further affecting word recall. The results were interpreted in terms of the dual coding hypothesis and indicated that pictures are encoded into separate visual and acoustic processing systems while words are primarily acoustically encoded.     

Picture-word differences in decision latency: An analysis of single and dual memory models

Semantic and perceptual size decision times for pictorial and verbal material were analyzed in the context of a unitary memory model and several dual memory models. Experiment 1 involved a same-different categorical judgment task. The results showed that picture-picture response latencies were 185 msec faster than the corresponding word-word latencies, and word-picture and picture-word latencies equaled the mean of these two extremes. Similarity of subcategory for “same” judgments led to faster decision latency for all presentation conditions. Additionally, a linear relationship was found between picture-picture and word-word latencies for individual item pairs. Experiment 2 involved a comparison of pictures and words across a. categorical judgment and a size judgment task. Pictures produced faster decision latencies in both tasks, and the latency diflerence between pictures and words was comparable across tasks. These data fit the predictions of a unitary memory model. Several variants of a dual memory model are rejected and those which fit the data require assumptions about storage and/or transfer time values which result in a functional regression to the unitary memory model.     

Knowledge about hand shaping and knowledge about objects

Our two experiments investigated associations between cognitive representations of objects and hand-shape categories. Hand configurations were partitioned according to prehensility and the size of the contacting surface, resulting in the classes: pinch, poke, palm, and clench. Experiment 1 elicited object names in response to configuration-name cues, provided ratings of the relevance of each configuration to a set of objects, and probed for the functions determining such relevance. Cueing with a configuration class elicited an associated object category with substantial intersubject agreement, and vice versa. Both the object categories and the functions associated with the four hand-configuration classes differed substantially, although the same object could be associated to some extent with multiple configurations, given variations in function. Experiment 2 elicited the names of hand-configuration classes in response to unfamiliar forms, which varied systematically in depth and the size of the projecting picture-plane surface. The modal response, response time, and degree of intersubject agreement were directly related to these variables. These structural variables, however, did not adequately predict shaping responses to real objects, as ascertained from Experiment 1. The results have implications for cognitive representation of motor categories and hand shaping in response to objects.