Reading long words embedded in sentences: informativeness of word halves affects eye movements

The possibility was explored that the informativeness of a specific region within a word can influence eye movements during reading. In Experiment 1, words containing identifying information either toward the beginning or toward the end were displayed asymmetrically around the point of fixation so that the reader was initially presented with either the informative or noninformative zone. Words were read with shorter summed initial fixation time when the reading was started from the informative zone. In Experiments 2 and 3, the target words were presented in sentences that were to be comprehended. More attention was given to the informative endings of words than to redundant endings. The latter were also skipped more often. The duration of the first fixation was not affected by information distribution within the word, whereas the second fixation duration was. The results of these experiments lend good support to the hypothesis of immediate lexical control over fixation behavior and to the notion of a convenient viewing position.     

Can dyslexia be treated? Treatment-specific and generalized treatment effects in dyslexic children's response to remediation

A total of 178 reading disabled children were randomly assigned to one of three treatment conditions providing training in word recognition and decoding skills (DS), oral and written language (OWLS), or classroom survival skills (CSS. an alternative treatment control). Pre- and post-treatment comparisons on an array of standardized and experimental measures indicated that the two experimental treatments (DS, OWLS) resulted in improvement on selected tests significantly greater than that resulting from a third treatment intervention which controlled for treatment time and individual attention (CSS). Effects specific to each experimental treatment were identified, as well as some generalized treatment advantages shared by both experimental groups at post-test. These results indicate that some of the deficits associated with developmental dyslexia are amenable to treatment. Greater generalization of treatment effects was observed following the DS than the OWLS treatment. While DS-instructed children exhibited better word recognition skills, however, their knowledge of grapheme-phoneme correspondence rules was not improved. Several OWLS-specific effects observed on experimental reading and language measures were not replicated on standardized tests which purport to measure the same skills. These results are discussed with respect to (i) possible mechanisms by which disabled readers may acquire word recognition skills, (ii) their failure to acquire and use grapheme-phoneme correspondence rules, and (iii) a possible reduced tendency in the present population to generalize newly acquired specific knowledge to related knowledge domains.     

Written spelling agraphia

When a disorder of single word writing is seen in conjunction with preserved oral spelling and intact written grapheme formation ("written spelling agraphia"), the deficit may be presumed to lie somewhere between letter choice and written motor output. Two potential deficits are considered: (1) visual letter codes are not activated properly and (2) the information contained within properly activated visual letter codes fails to reach intact graphic motor patterns. Two patients with written spelling agraphia were each given a series of tests aimed at distinguishing between the two possibilities. Results suggest that the written spelling agraphia seen in these two patients arises from different underlying deficits. The results are discussed in terms of the patients' CT scan lesion sites, which were markedly different.     

Neuropsychological functioning in hemiparkinsonism

A standardized neuropsychological battery including measures of intellectual cognitive, memory, attention-concentration, language, abstraction and mental flexibility, and sensory and motor functions was administered to 21 hemiparkinsonian patients (14 with right side and 7 with left side symptoms) and 17 controls matched for age and education. Patients were impaired in all functions except sensory. For motor functions, impairment was ipsilateral to the side of symptoms. For cognitive functions, right side symptoms were associated with verbal deficits whereas left side symptoms were associated with spatial deficits. Thus, a pattern of neuropsychological deficits consistent with the lateralization of motor symptoms may appear in the early stages of the disease.     

Selective spatial attention and length representation in normal subjects and in patients with unilateral spatial neglect

The aim of this study was to assess whether perceptual representation along the horizontal axis is affected by hemispace position of the stimulus or by orienting attention to one side. Ten control subjects and 10 right brain damaged patients with left unilateral spatial neglect (USN) were asked to bisect lines of five lengths in three space positions (left, center, right) and under three cueing conditions (no cue, left cue, right cue). Normal controls showed significant displacement of bisection opposite to the side of hemispace presentation and toward the side of cueing. USN patients showed a bisection error toward the right end which increased with lines placed in the left hemispace and decreased with lines placed in the right hemispace and when attention was oriented toward the left side. We conclude that (1) In absence of cues normal subjects tend to overestimate the portions of space closer to their body midline; (2) both normal and USN patients tend to overestimate portions of space that they direct their attention to; (3) USN patients' performance without cueing is consistent with an attentional shift toward the right hemispace implying a gradient of overestimation of the right-most portions of space. A common neural substratum for directing attention and space representation can explain these findings.     

On the development of procedural knowledge

Amnesic patients demonstrate by their performance on a serial reaction time task that they learned a repeating spatial sequence despite their lack of awareness of the repetition (Nissen & Bullemer, 1987). In the experiments reported here, we investigated this form of procedural learning in normal subjects. A subgroup of subjects showed substantial procedural learning of the sequence in the absence of explicit declarative knowledge of it. Their ability to generate the sequence was effectively at chance and showed no savings in learning. Additional amounts of training increased both procedural and declarative knowledge of the sequence. Development of knowledge in one system seems not to depend on knowledge in the other. Procedural learning in this situation is neither solely perceptual nor solely motor. The learning shows minimal transfer to a situation employing the same motor sequence.     

Effect of backward priming on word recognition in single-word and sentence contexts

Backward priming was investigated under conditions similar to those used in lexical ambiguity research. Subjects received prime-target word pairs that were associated either unidirectionally (BABY-STORK) or bidirectionally (BABY-CRY). In the first experiment, targets were presented 500 ms following the onset of visual primes, and subjects made naming or lexical decision responses to the targets. Forward priming was obtained in all conditions, while backward priming (i.e., priming for pairs in which there was a unidirectional target-to-prime association, as in BABY-STORK) occurred only with lexical decision. In the second experiment, primes were presented auditorily, either in isolation or in a sentence. Targets followed the offset of the primes either immediately or after 200 ms. Backward priming occurred with both response tasks, but only when the prime was an isolated word. In addition, backward priming decreased over time with the naming task, but not with lexical decision. These results suggest that the locus of the backward priming effect is different for the two response tasks. Further, the lack of a backward priming effect with sentence contexts suggests that backward priming cannot account for the demonstrations of multiple access in the lexical ambiguity literature. These results, therefore, support a context-independent view of lexical access.     

Insight without awareness: On the interaction of verbalization, instruction and practice in a simulated process control task

Four experiments in which subjects learned to control two versions of a complex simulated process control task show that verbalizable knowledge of procedures used to perform these tasks is very limited and is acquired late in learning. Individual learning curves associated with these tasks showed sudden improvements in performance, which were not accompanied by a similar increase in verbalizable knowledge. It was also found that verbal instructions consisting of exemplar memorization, strategies for rule induction, simple heuristics, and experts' instructions were all effective in enhancing novice subjects' performance. A theoretical framework is proposed in which subjects draw on two separate but interacting knowledge structures to perform these tasks. One knowledge structure is based on memory for past experiences (close analogies), and the other is based on one's current mental model of the task. Implicit sets of competing rules that control response selection are derived from both sources of knowledge. It is suggested that dissociations between task performance and verbalizing occur because memory-based processing tends to have more control over response selection because of its greater specificity, whereas a mental model tends to be the preferred mode for verbal reporting because of its greater accessibility.     

Base-rate effects in category learning: a comparison of parallel network and memory storage-retrieval models

Exemplar-memory and adaptive network models were compared in application to category learning data, with special attention to base rate effects on learning and transfer performance. Subjects classified symptom charts of hypothetical patients into disease categories, with informative feedback on learning trials and with the feedback either given or withheld on test trials that followed each fourth of the learning series. The network model proved notably accurate and uniformly superior to the exemplar model in accounting for the detailed course of learning; both the parallel, interactive aspect of the network model and its particular learning algorithm contribute to this superiority. During learning, subjects' performance reflected both category base rates and feature (symptom) probabilities in a nearly optimal manner, a result predicted by both models, though more accurately by the network model. However, under some test conditions, the data showed substantial base-rate neglect, in agreement with Gluck and Bower (1988b).     

Social and life skill competence in potential early school-leavers

Competencies in social and life skills of a group of students expecting to leave school at the end of Grade 10 in Australia is compared with groups expecting to continue. Academic performance and skills were also assessed. The results of the study indicated that the potential early school-leavers were disadvantaged both socio-economically and academically. But, surprisingly, the findings indicated that they were not significantly different from the other two groups of students targeted in the study in terms of their social and life skills. The results imply that potential early leavers in school populations may be unnecessarily disadvantaged because school programmes, in concentrating on a narrow range of cognitive skills, do not build on personal competency skills already possessed by students of all levels of ability. Whilst this is the case, potential early school-leavers will be likely to continue to be disaffected and disadvantaged educationally.