Evaluation of the attentional capacities and working memory of early and late blind persons

Although attentional processes and working memory seem to be significantly involved in the daily activities (particularly during navigating) of persons who are blind and who use these abilities to compensate for their lack of vision, few studies have investigated these mechanisms in this population. The aim of this study is to evaluate the selective, sustained and divided attention, attentional inhibition and switching and working memory of blind persons. Early blind, late blind and sighted participants completed neuropsychological tests that were designed or adapted to be achievable in the absence of vision. The results revealed that the early blind participants outperformed the sighted ones in selective, sustained and divided attention and working memory tests, and the late blind participants outperformed the sighted participants in selective, sustained and divided attention. However, no differences were found between the blind groups and the sighted group in the attentional inhibition and switching tests. Furthermore, no differences were found between the early and late blind participants in this set of tests. These results suggest that early and late blind persons can compensate for the lack of vision by an enhancement of the attentional and working memory capacities.     

医师知识结构和思维方式与肺血栓栓塞症诊断

肺血栓栓塞症是常见的临床病症,因其临床表现多样,易发生误诊漏诊而导致较高的病死率。但“凡事预则立,不预则废”,充分掌握肺血栓栓塞症的知识、以正确的思维方式引导临床诊疗可以有效减少和避免误诊漏诊。     

Cognitive sophistication does not attenuate the bias blind spot

The so-called bias blind spot arises when people report that thinking biases are more prevalent in others than in themselves. Bias turns out to be relatively easy to recognize in the behaviors of others, but often difficult to detect in one's own judgments. Most previous research on the bias blind spot has focused on bias in the social domain. In 2 studies, we found replicable bias blind spots with respect to many of the classic cognitive biases studied in the heuristics and biases literature (e.g., Tversky & Kahneman, 1974). Further, we found that none of these bias blind spots were attenuated by measures of cognitive sophistication such as cognitive ability or thinking dispositions related to bias. If anything, a larger bias blind spot was associated with higher cognitive ability. Additional analyses indicated that being free of the bias blind spot does not help a person avoid the actual classic cognitive biases. We discuss these findings in terms of a generic dual-process theory of cognition. (PsycINFO Database Record (c) 2012 APA, all rights reserved).     

Progressive locomotor recalibration during blind walking

Blind walking has become a common measure of perceived target location. This article addresses the possibility that blind walking might vary systematically within an experimental session as participants accrue exposure to nonvisual locomotion. Such variations could complicate the interpretation of blind walking as a measure of perceived location. We measured walked distance, velocity, and pace length in indoor and outdoor environments (1.5-16.0 m target distances). Walked distance increased over 37 trials by approximately 9.33% of the target distance; velocity (and to a lesser extent, pace length) also increased, primarily in the first few trials. In addition, participants exhibited more unintentional forward drift in a blindfolded marching-in-place task after exposure to nonvisual walking. The results suggest that participants not only gain confidence as blind-walking exposure increases, but also adapt to nonvisual walking in a way that biases responses toward progressively longer walked distances.     

Smell and taste function in the visually impaired

Surprisingly few quantitative studies have addressed the question of whether visually impaired individuals evidence, perhaps in compensation for their loss of vision, increased acuteness in their other senses. In this experiment we sought to determine whether blind subjects outperform sighted subjects on a number of basic tests of chemosensory function. Over 50 blind and 75 sighted subjects were administered the following olfactory and gustatory tests: the University of Pennsylvania Smell Identification Test (UPSIT); a 16-item odor discrimination test; and a suprathreshold taste test in which measures of taste-quality identification and ratings of the perceived intensity and pleasantness of sucrose, citric acid, sodium chloride, and caffeine were obtained. In addition, 39 blind subjects and 77 sighted subjects were administered a single staircase phenyl ethyl alcohol (PEA) odor detection threshold test. Twenty-three of the sighted subjects were employed by the Philadelphia Water Department and trained to serve on its water quality evaluation panel. The primary findings of the study were that (a) the blind subjects did not outperform sighted subjects on any test of chemosensory function and (b) the trained subjects significantly outperformed the other two groups on the odor detection, odor discrimination, and taste identification tests, and nearly outperformed the blind subjects on the UPSIT. The citric acid concentrations received larger pleasantness ratings from the trained panel members than from the blind subjects, whose ratings did not differ significantly from those of the untrained sighted subjects. Overall, the data imply that blindness, per se, has little influence on chemosensory function and add further support to the notion that specialized training enhances performance on a number of chemosensory tasks.     

Blind children recognizing tactile pictures respond like sighted children given guidance in exploration

Theory of tactile pictures argues that untrained blind subjects can recognize raised, outline pictures. It contends the blind person’s knowledge of the shapes of common objects is like that of the sighted, and the blind person’s pictorial abilities use the same principles as the sighted person’s. To test this theory, blind children (aged 8–13) and blindfolded age-matched sighted children were asked to identify raised-line drawings of common objects. Their performances were correlated. In addition, the blind children identified more than sighted children exploring the pictures actively, but the same number of pictures as sighted children who were given passive, guided exploration. We argue blind and sighted children use the same principles to identify the pictures, but the blind have superior exploration skills. The differences in the effects of exploration skills on recognition scores are minimized when the sighted children are given guidance, since the sighted children then have efficient contact with the displays, and the performance of the sighted and the blind is then governed by the same principles, without one group benefitting from advantages in exploration skills.     

Learning implicitly to produce avoided behaviours

The literature on repetition processing reveals an intriguing paradox between the particular salience of repetitions, which makes them easy to learn, and a tendency to avoid them when generating sequences. The aim of this experiment was to study the extent to which children can learn to produce these avoided behaviours by means of an artificial grammar paradigm using generation tests with implicit or explicit instructions. The analysis of the control group's performance confirmed the presence of a spontaneous tendency to avoid generating repetitions. A comparison with chance revealed that the children learned to produce repetitions in the explicit test but not in the implicit test. However, a comparison with the control group showed that learning nonetheless occurred in the experimental group with the implicit test. The discussion focused on this antirepetition behavioural bias and how it interacted with the type of information processes elicited by the tests selected for assessing implicit learning effects.     

Tactile perception in blind Braille readers: a psychophysical study of acuity and hyperacuity using gratings and dot patterns

It is not clear whether the blind are generally superior to the sighted on measures of tactile sensitivity or whether they excel only on certain tests owing to the specifics of their tactile experience. We compared the discrimination performance of blind Braille readers and age-matched sighted subjects on three tactile tasks using precisely specified stimuli. Initially, the blind significantly outperformed the sighted at a hyperacuity task using Braille-like dot patterns, although, with practice, both groups performed equally well. On two other tasks, hyperacute discrimination of gratings that differed in ridge width and spatial-acuity-dependent discrimination of grating orientation, the performance of the blind did not differ significantly from that of sighted subjects. These results probably reflect the specificity of perceptual learning due to Braille-reading experience.     

Near-Death and Out-of-Body Experiences in the Blind: A Study of Apparent Eyeless Vision

This article reports the results of an investigation into near-death and out-of-body experiences in 31 blind respondents. The study sought to address three main questions: (1) whether blind individuals have near-death experiences (NDEs) and, if so, whether they are the same as or different from those of sighted persons; (2) whether blind persons ever claim to see during NDEs and out-of-body experiences (OBEs); and (3) if such claims are made, whether they can ever be corroborated by reference to independent evidence. Our findings revealed that blind persons, including those blind from birth, do report classic NDEs of the kind common to sighted persons; that the great preponderance of blind persons claim to see during NDEs and OBEs; and that occasionally claims of visually-based knowledge that could not have been obtained by normal means can be independently corroborated. We present and evaluate various explanations of these findings before arriving at an interpretation based on the concept of transcendental awareness.     

人文关怀与青光眼的诊治

青光眼是一类不可逆性致盲性眼病,早期诊断、早期治疗具有十分重要的意义.眼科医师在青光眼早期诊断中应遵循最优化原则,避免过度医疗,给予患者更多的人文关怀.     

We have a prejudice against ourselves—Sentiment,ethics, and reason

Briefly stated my point is that the well-being of each person in a community conceived abstractly may be all too easily sacrificed for the sake of the abstraction. Physicians may offer critically ill patients places in programs of experimental treatment, but there is commonly a catch to the offer. To take part in a program of clinical experiment a patient must not only risk a possible failure of a fresh drug and the chance of destructive side effects from the drug, but the patients must risk only getting the traditional treatment along with a placebo rather than the experimental drug. Placebo control, double blind critical protocols for testing effects of fresh drugs on critically ill patients are a commonplace. I question the scientific objectivity of the protocols and the underlying ethic, and suggest use of alternate protocols. Experimental tests in the treatment gram-negative bacteria blood infections, muscular dystrophy, and AIDS and AIDS-related diseases are examples.     

The effects of imagery instructions on total congenital blind recall

Abstract

Research on the performance of total congenital blind subjects in imagery tasks is of particular interest because it helps to evaluate the consequences of their lack of visual experience. The present paper examines some points which remained unclear in the preceding research on the effects of imagery instructions on the recall of blind subjects. In Experiment 1 it is shown that, in a free recall task of unrelated nouns, the blind may take advantage of imagery instructions, independently of the particular requirement to form either common or bizarre images. In Experiment 2 the multiple image processing deficit of the blind found by De Beni and Cornoldi (1988) was again observed, but the effect was not found when the same quantity of material had to be processed verbally. Results are interpreted as showing that, although the blind may follow imagery instructions, their visual handicap creates specific difficulties in creating interactive images involving several items at the same time.     

The serial-parallel dilemma: A case study in a linkage of theory and method

The question as to whether humans perceive, remember, or cognize psychological items simultaneously (i.e., in parallel) or sequentially (i.e., serially) has been of interest to philosophers and psychologists since at least the 19th century. The advent of the information-processing approach to cognition in the 1960s reopened the inquiry, initiating a flood of experiments and models in the literature. Surprisingly for so elemental an issue, persuasive experimental tests have, until recently, proven rather elusive. Several decades of theoretical, methodological, and experimental effort, propelled and shaped by a meta-theoretical perspective, are leading to powerful strategies for assessing this and related cognitive issues. The present article reviews the theoretical and empirical history of these inquiries and details situations in which decisive experimental tests are possible.     

Spatial representation by blind and sighted children

Spatial representation by 72 blind and blindfolded sighted children between the ages of 6 and 11 was tested in two experiments by mental rotation of a raised line under conditions of clockwise varied directions.Experiment 1 showed that the two groups were well matched on tactual recognition and scored equally badly on matching displays to their own mentally rotated position.Experiment 2 found the sighted superior in recall tests. There was a highly significant interaction between sighted status and degree of rotation. Degree of rotation affected only the blind. Their scores were significantly lower for rotating to oblique and to the far orthogonal directions than to near orthogonal test positions. On near orthogonals the blind did not differ from the sighted.Age was a main effect, but it did not interact with any other variable. Older blind children whose visual experience dated from before the age of 6 were superior to congenitally blind subjects, but not differentially more so on oblique directions.The results were discussed in relation to hypotheses about the nature of spatial representation and strategies by children whose prior experience derived from vision or from touch and movement.     

Report on blind subjects' tactile and auditory recognition for environmental stimuli.

In two related experiments on recognition-on touch and audition-accuracy rates were obtained from congenitally blind subjects and compared with those for normally sighted subjects. In Exp. 1, 5 blind subjects inspected, i.e., handled, 150 common objects and were tested after a delay of 7 days. In Exp. 2, 9 blind subjects listened to 194 naturalistic sounds and were also tested after a 7-day delay. Accuracy of tactile recognition for the blind was 89.4% while it was 87.9% for the normally sighted. Sound recognition by blind subjects was 76.6% and for the normally sighted it was 78.4%. Neither difference was statistically significant.     

Performance of early-blind and sighted children on olfactory tasks

The goal of the study was to test whether children with congenital or early-onset blindness outperform sighted children on olfactory tasks. Measures of olfactory sensitivity, odour recognition, and odour labeling were obtained. The results show that the blind children were more proficient at correctly labeling 25 common odours than were matched sighted children. However, the blind were not more sensitive to a target odour, nor more proficient at choosing a correct odour label from a list of four. Together, the data point to a circumscribed advantage of blind children at self-generating and retrieving odour labels and, as such, to a limited, but still compensatory, cognitive function.     

Police endorsement of color‐blind racial beliefs and propensity to interact with youth of color

The beliefs of police, as the point of first contact with the justice system, may help to explain disproportionate minority contact between police and young people. Color‐blind racial beliefs, a form of implicit racism in which racial differences are denied, are more strongly endorsed by police than by laypeople. Using a 2 (youth race) × 3 (offense severity) experimental design, 339 officers participated in an online study examining the influence of youth race, offense severity, and officers' color‐blind racial beliefs on officers' reported likelihood of interacting with young people. Officers with lower levels of color‐blind beliefs reported they would be less likely to interact with Black youth. Additionally, attrition analyses indicated that officers assigned to the Black youth condition were more likely to drop out when asked to complete the measure of color‐blind beliefs. Policy and practice implications are discussed, with a focus on promoting greater discussion of color‐blind ideologies in multicultural trainings for police officers and increasing frank discussions about race and racial issues.     

Acquisition of navigation by chimpanzees (Pan troglodytes) in an automated fingermaze task

These experiments investigated how chimpanzees learn to navigate visual fingermazes presented on a touch monitor. The aim was to determine whether training the subjects to solve several different mazes would establish a generalized map-reading skill such that they would solve new mazes correctly on the first presentation. In experiment 1, two captive adult female chimpanzees were trained to move a visual object (a ball) with a finger over the monitor surface toward a target through a grid of obstacles that formed a maze. The task was fully automated with storage of movement paths on individual trials. Training progressed from very simple mazes with one obstacle to complex mazes with several obstacles. The subjects learned to move the ball to the target in a curved path so as to avoid obstacles and blind alleys. After training on several mazes, both subjects developed a high level of efficiency in moving the ball to the target in a path that closely approached the ideal shortest path. New mazes were then presented to determine whether the subjects had acquired a more generalized maze-solving performance. The subjects solved 65–100% of the new mazes the first time they were presented by moving the ball around obstacles to the target without making detours into blind alleys. In experiment 2, one of the chimpanzees was trained using mazes with two routes to the target. One of the routes was blocked at one of many possible locations. After training to avoid the blind alley in different mazes, new mazes were presented that also had one route blocked. The subject correctly solved 90.7% of the novel mazes. When the mazes had one short and one long open route to the target the subject preferred the shorter route. When the short route was blocked, the subject solved only 53.3% of the mazes because of the preference for the shorter route even when blocked. The overall results suggest that with the training methods used the subjects learned to solve specific mazes with a trial-and-error method. Although both subjects were able to solve many of the novel mazes they did not fully develop a more general "map-reading" skill. Accepted after revision: 30 July 2001 Electronic Publication     

The analysis of drawing from memory performance in brain-damaged patients

The drawing from memory task is frequently used in cognitive neuropsychology to investigate visual processing impairments. However, in surprising contrast to most other neuropsychological tests, the analyses of results on this task are most often based solely on qualitative judgements about the normality of a patient's performance. In most case reports, these judgements are not made with reference to normative data and are not made by individuals who are impartial with respect to the study (that is, using a blind rating procedure). There are several grounds for arguing that such analyses are inadequate. First, seemingly abnormal drawings made by a patient may well be within the range of performance shown by control subjects. Second, judgments that are not based on a blind rating procedure are likely to be influenced by knowledge about the patient's performance on other tasks. We describe an alternative assessment procedure that addresses both of these concerns.