Nonverbal categorization in fluent and nonfluent anomic aphasics

This study aimed to demonstrate that the naming difficulties of a particular group of aphasics, namely, fluent aphasics, are related to an underlying inability to organize feature set information. In order to test this hypothesis, the performance of fluent aphasics, nonfluent aphasics, and a nonaphasic brain-injured control group, was examined on a nonverbal categorization task, which was carefully structured in terms of instance typicality. Scores of visuoperceptual and naming tests were correlated with categorization task errors. As predicted, fluent aphasics showed a significant deficit in performance on the categorization task in comparison with other subjects. Differences in the nature of the errors the fluent aphasics made suggested that their problems were related to difficulties in abstracting the prototype for each category and in sorting category members with reference to these prototypes. For fluent aphasics, but not other subjects, a significant correlation was found between categorization task performance and naming ability.     

Individual differences in mental animation during mechanical reasoning

In three experiments we tested the effects of spatial visualization ability on performance of a motion-verification task, in which subjects were shown a diagram of a mechanical system and were asked to verify a sentence stating the motion of one of the system components. We propose that this task involves component processes of (1) sentence comprehension, (2) diagram comprehension, (3) text-diagram integration, and (4) mental animation. Subjects with law spatial ability made more errors than did subjects with high spatial ability on this task, and they made more errors on items in which more system components had to be animated to solve the problem. In contrast, the high-spatial subjects were relatively accurate on all trials. These results indicate that spatial visualization is correlated with accuracy on the motion-verification task and suggest that this correlation is primarily due to the mental animation component of the task. Reaction time and eye-fixation data revealed no differences in how the high- and low-spatial subjects decomposed the task. The data of the two groups of subjects were equally consistent with a piecemeal model of mental animation, in which components are animated one by one in order of the causal chain of events in the system.     

Information processing and reasoning with premises that are empirically false: Interference,working memory,and processing speed

In this study, we looked at the contributions of individual differences in susceptibility to interference and working memory to logical reasoning with premises that were empirically false (i.e., not necessarily true). A total of 97 university students were given a sentence completion task for which a subset of stimuli was designed to generate inappropriate semantic activation that interfered with the correct response, a measure of working memory capacity, and a series of logical reasoning tasks with premises that were not always true. The results indicate that susceptibility to interference, as measured by the error rate on the relevant subset of the sentence completion task, and working memory independently account for variation in reasoning performance. The participants who made more errors in the relevant portion of the sentence completion task also showed more empirical intrusions in the deductive reasoning task, even when the effects of working memory were partialed out. Working memory capacity was more clearly related to processes involved in generating uncertainty responses to inferences for which there was no certain conclusion. A comparison of the results of this study with studies of children's reasoning suggests that adults are capable of more selective executive processes than are children. An analysis of latency measures on the sentence completion task indicated that high working memory participants who made no errors on the sentence completion task used a strategy that involved slower processing speed, as compared with participants with similar levels of working memory who did make errors. In contrast, low working memory participants who made no errors on the sentence completion task had relatively shorter reaction times than did comparable participants who did make errors.     

Visuo‐spatial working memory in navigation

Two experiments employed dual task techniques to explore the role of working memory in route learning and subsequent route retrieval. Experiment 1 involved contrasting performance of two groups of volunteers respectively learning a route from a series of map segments or a series of visually presented nonsense words. Both groups performed learning and recognition under articulatory suppression or concurrent spatial tapping. Both concurrent tasks had an overall disruptive effect on each learning task. However, spatial tapping disrupted route recognition rather more than did articulatory suppression, while the nonsense word recognition was impaired more by articulatory suppression than by concurrent spatial tapping. Experiment 2 again used dual task methodology, but explored route learning by asking volunteers to follow the experimenter through the winding streets of a medieval European town centre. Retrieval involved following the same route while the experimenter followed and noted errors in navigation. Overall the results partially replicated those of Experiment 1 in that both concurrent tasks interfered with route learning. However, volunteers with high spatial ability appeared more affected by the concurrent spatial tapping task, whereas low spatial subjects appeared more affected by the concurrent articulatory suppression task. Results are interpreted to suggest that different aspects of working memory are involved in learning a route from a map with a greater emphasis on visuo‐spatial resources, but in tasks set in real environments where many cues of a varied nature are available, only high spatial ability subjects appear to rely heavily upon the visuospatial component of working memory. Copyright © 2002 John Wiley & Sons, Ltd.     

Behavior of depressed subjects in problem solving groups

This study investigated leadership selection in groups in relation to level of depression of group members. On the basis of MMPI-D and DACL scores 66 subjects were organized into groups of six to eight people consisting of all depressed, all nondepressed, or half depressed and half nondepressed subjects. Subjects performed a problem solving task alone and in groups and completed a questionnaire on leadership choice and group performance. Results indicate that nondepressed group members talked more frequently, were rated as more important contributors, and were selected as leaders more frequently than depressed members. In addition, mixed groups were perceived as more efficient and enjoyable by group members than the unmixed groups. There were no significant differences between depressed and nondepressed subjects on performance of the problem solving task whether working alone or in groups. Results were discussed in relation to other literature on the interpersonal behavior of depressed persons.     

任务图式对文章修改的影响研究

本研究探讨任务图式对文章修改的影响。高低水平的作者先完成一个写作任务,再修改文章的初稿。修改时,实验组学生先接受关于正确修改的任务图式指导,控制组学生则直接进行修改。实验结果表明,任务图式指导有明显的主效应,高低水平作者均提高了对字面错误与意义错误的正确修改,而水平间的差异主要表现在意义错误的修改上。本研究还分析了任务图式指导对修改的字数(包括改变意义与保留意义的字数)、修改的句法水平(包括字、词和句子)以及修改的方式(包括插入、替换、删除和移动句子)的影响。     

小学生系列回忆中移动和重复错误特征的研究

以小学一、三、五年级学生为被试,以同音汉字为实验材料,要求被试完成系列回忆任务。实验发现：移动错误随年级的增高而减少,年级差异显著;移动错误出现最多的是在移动距离为1个和2个的时候,移动距离差异显著;重复错误年级差异和移动距离差异均不明显。     

When do letter features migrate? A boundary condition for feature-integration theory

Feature-integration theory postulates that a lapse of attention will allow letter features to change position and to recombine as illusory conjunctions (Treisman & Paterson, 1984). To study such errors, we used a set of uppercase letters known to yield illusory conjunctions in each of three tasks. The first, a bar-probe task, showed whole-character mislocations but not errors based on feature migration and recombination. The second, a two-alternative forced-choice detection task, allowed subjects to focus on the presence or absence of subletter features and showed illusory conjunctions based on feature migration and recombination. The third was also a two-alternative forced-choice detection task, but we manipulated the subjects' knowledge of the shape of the stimuli: In the case-certain condition, the stimuli were always in uppercase, but in the case-uncertain condition, the stimuli could appear in either upper- or lowercase. Subjects in the case-certain condition produced illusory conjunctions based on feature recombination, whereas subjects in the case-uncertain condition did not. The results suggest that when subjects can view the stimuli as feature groups, letter features regroup as illusory conjunctions; when subjects encode the stimuli as letters, whole items may be mislocated, but subletter features are not. Thus, illusory conjunctions reflect the subject's processing strategy, rather than the architecture of the visual system.     

Effects of own group success or failure on judgements of task performance by children of different ethnicities

Children in majority groups hold favourable attitudes toward members of their own group, whereas those in minority groups typically hold more favourable attitudes toward majority than own group members. It was expected that when evaluating task outcomes, majority group children would display own group favouritism, and minority children would show other group favouritism or ‘reverse ethnocentrism’. In this study, white and Native Indian elementary school children saw a video of a white and native child listening to sounds and trying to identify them. One-third of subjects saw white models correct more often than Native models, one-third saw Native models more often correct than white models, and the remaining third saw both models correct on an equal number of trials. When white models were successful, children from both groups made more positive evaluations of, optimistic predictions about, and internal attributions for task outcomes. When these models did poorly, negative attributes were deemphasized and task outcomes were attributed to external factors. Success by native models was attributed to external factors and task outcomes had little influence on predictions or evaluations. When native models were unsuccessful subjects accentuated negative attributes of these models and made internal attributions for their failures. Results were discussed in terms of cognitive and motivational theories of social judgements.     

Control of saccades in Parkinson's disease

Parkinson's patients (PD) made pro- and antisaccades: In the no-delay condition, the target appeared concurrent with the GO signal. In the delay condition, the target appeared before the signal for movement. Second, we probed spatial working memory in PD. Subjects looked to the remembered locations of sequential targets. In the no-delay prosaccade condition, PD had faster reaction times, made more express saccades, and exhibited hypometria. In the no-delay antisaccade condition, PD had longer reaction times and made more direction errors. In the delay tasks, PD made more direction errors and had more difficulty withholding a movement. PD made more sequencing errors in the spatial working memory task. These findings are consistent with a basal ganglia pathophysiology influencing eye movement processing in the frontal cortex.     

Some aspects of language comprehension in anterior aphasia

The competency of language comprehension was evaluated in three groups: anterior aphasics, posterior aphasics, and normal control subjects. Test material was divided into two sentence groups (Fill in the Blank and True/False) emphasizing either (1) semantic, “real world,” identity words or (2) syntactic, relational words, and one paragraph interpretation task. Matching auditory and visual (written) presentations were given. The control subjects performed almost flawlessly but many errors were made by each aphasia group. Qualitative study revealed a marked difference in the comprehension problem of the two groups. The anterior aphasic group performed well on semantically weighted sentences but made errors on syntactically weighted material, regardless of mode of presentation. In contrast, the posterior aphasics made almost the same number of errors on both types of material, regardless of mode of presentation. These findings support the concept of defective language comprehension in anterior aphasia and further suggest that the defect centers on the syntactical structures which are also poorly handled in expressive output.     

Effect of subvocalization on memory for speech sounds.

Subjects in two groups were presented with sequences of 6 consonant-vowel syllables for ordered recall. Subjects in both groups were trained to suppress subvocalization. Only subjects in the feedback group were asked to suppress subvocalization during the experiment, while subjects in the no-feedback group were allowed to subvocalize during the memory task. Analysis of the electromyographic records showed a large decrease in subvocalization in the feedback condition, and results of the memory task revealed an increase in errors for this group. However, a comparison of errors within each group revealed an identical pattern of overall errors and intrusion errors on subvocalization and nonsubvocalization trials, and these results were identical in both groups. The results suggest that requiring subjects to simultaneously suppress subvocalization and remember syllables depresses performance slightly, but encoding of speech sounds in short-term memory occurs independently of subvocal activity during the memory task.     

Pictorial perspective: perception of size, linear, and texture perspective in children and adults

Perception of size, linear, and texture perspective was investigated in third-grade and sixth-grade children and in college adults in three separate studies. A matching task required the observer to choose from a set of four alternative real scenes the correct match for the test stimulus, which was either a picture or a real scene. Correct performance required that the subject utilize perspective information for both size and distance distance relations. Erroneous choices available to the subject indicated errors in size judgement, in distance judgment, or in both simultaneously. View was either restricted at the correct station point or was free, with head motion. There were no significant effects of grade level. For all three groups, mean percent correct was nearly 100% with the real-scene test stimuli, and significantly below the chance level with the picture test stimuli. Errors in size judgment occurred most frequently, indicating that the geometrically correct rate of perspective convergence was too rapid to be seen by the subjects as perceptually acceptable. With size-perspective information alone, the number of size plus distance errors also increased significantly. There was no significant effect of viewing condition.     

Squinting with the mind’s eye: Effects of stimulus resolution on imaginal and perceptual comparisons

Subjects either viewed or visualized arrays that were divided into four quadrants, with each quadrant containing a set of stripes. In two experiments, one array contained only relatively narrow (high-resolution) stripes, and one contained only relatively thick (low-resolution) stripes. The subjects compared sets of stripes in different quadrants according to their length, spacing, orientation, or width. When the subjects visualized the arrays, they required much more time to compare high-resolution patterns than low-resolution patterns; when the subjects saw the arrays, they evaluated both types of arrays equally easily. In addition, the results from the third experiment provide strong evidence that people use imagery in this task; in one condition, the subjects evaluated oblique sets of stripes, and in another condition, they evaluated vertical and horizontal stripes. In both imagery and perception, the subjects made more errors when evaluating oblique stimuli; in imagery, they also required more time to evaluate oblique stimuli. The results suggest that additional effort is required in imagery to represent visual patterns with high resolution. This finding demonstrates that, although imagery and perception may activate common brain regions, it is more difficult to represent high-resolution information in imagery than in perception.     

What Stroop tasks can tell us about selective attention from childhood to adulthood

A rich body of research concerns causes of Stroop effects plus applications of Stroop. However, several questions remain. We included assessment of errors with children and adults (N = 316), who sat either a task wherein each block employed only trials of one type (unmixed task) or where every block comprised of a mix of the congruent, neutral, and incongruent trials. Children responded slower than adults and made more errors on each task. Contrary to some previous studies, interference (the difference between neutral and incongruent condition) showed no reaction time (RT) differences by group or task, although there were differences in errors. By contrast, facilitation (the difference between neutral and congruent condition) was greater in children than adults, and greater on the unmixed task than the mixed task. After considering a number of theoretical accounts, we settle on the inadvertent word‐reading hypothesis, whereby facilitation stems from children and the unmixed task promoting inadvertent reading particularly in the congruent condition. Stability of interference RT is explained by fixed semantic differences between neutral and incongruent conditions, for children versus adults and for unmixed versus mixed task. We conclude that utilizing two tasks together may reveal more about how attention is affected in other groups.     

Processes That Mediate the Relationship Between a Group Goal and Group Member Performance

The impact of a group goal on the performance of anonymous and nonin- teracting group members performing an additive group task was tested. Pro- cesses believed to mediate the effect, the role of self-set individual goals, the impact of information about the group's previous performance on the task (group knowledge of results; GRPKR) on goal commitment, and the motiva- tional basis of the goal were also assessed. Seventeen groups of three to five people performed two trials of an idea generation task. In the GOAL/GRPKR condition, group members were assigned a group goal for Session 2 and received information about the group's performance for Session 1. In the goal without knowledge of results (GOAL/NOKR) condition, group mem- bers were assigned a group goal for Session 2 without GRPKR. In the NO- GOAL condition, group members worked without a goal and without GRPKR. In each condition, group members worked on the task without talk- ing to other group members and individual contributions to the group prod- uct were unknown to others. Self-reports of effort, changes in individual performance strategies from Rial 1 to Rial 2, self-set individual goals, goal commitment, and personal challenge were collected. Results showed that (a) group members working toward a performance goal outperformed those working without a goal, b) information about the group's previous perfor- mance on the task did not influence commitment to the goal or performance, (c) changes in individual performance strategies mediated the group goal ef- fect but self-reports of effort invested in the task did not, (d) g m ~ p members working toward a group goal felt more personal challenge than group mem- bers working without a goal, and (e) self-set individual goals can not account for the group goal effect. The implications of these results for models of group goals and group performance are discussed.     

False working memories? Semantic distortion in a mere 4 seconds

False memories are well-established, episodic memory phenomena: Semantically related associates are confidently and erroneously remembered as studied items. We report four experiments yielding similar effects in a working memory paradigm. Four semantically related words were retained over a brief interval. Whether or not the interval was filled with a math verification task, semantically related lures were mistakenly recognized as members of the memory set and took longer to reject than did unrelated negative probes. In a short-term recall task, semantic intrusions exceeded other errors (e.g., phonemic). Our results demonstrate false memory effects for a subspan list when a mere 4 sec was given between study and test. Such rapid semantic errors presumably result from associative processing, may be related to familiarity-based proactive interference in working memory, and are consistent with recent models that integrate short- and long-term memory processes.     

Individual differences in cognition: Some relationships between personality and memory

Individual differences in cognition were studied in the form of the hypothesis that arousal, as indexed by personality measures of extraversion and neuroticism, affects the way in which verbal material is organized in memory. Subjects pretested on measures of these personality variables participated in either a paired-associates learning or a free-recall experiment. On the paired-associates task, subjects who were thought to be high on arousal made fewer errors when response terms were semantically similar than low arousal subjects. On the other hand, subjects thought low on arousal made fewer errors when response words were phonetically similar than high arousal subjects. On the free-recall task, low arousal subjects were found to cluster words together on the basis of semantic category at a higher rate than high arousal subjects. These results were taken to support the view that high arousal (as indexed by personality measures) leads to a focus on the physical aspects of verbal material, whereas low arousal leads to a memory organized around semantic aspects. The implications of these findings for other views of memory are discussed.     

Social Comparison and Goal Setting in Brainstorming Groups1

Two studies were conducted to examine the influence of individual and group goal setting on brainstorming performance. Results from the studies indicated that the individual goals of nominal participants were higher than the individual goals of interactive participants. Group goal setting by consensus led to the lowest goals. There was no influence of goal setting on group brainstorming performance. However, participants who set goals rated their individual performance more favorably than did participants who did not set goals. The low group goals set by interactive groups are discussed in terms of assumptions made regarding the ability of other group members and the detrimental effects of group interaction.     

An analysis of performance by pre-school children on the KRISP and on a length discrimination task

The speed and accuracy of judgements made by pre-school children on the Kansas Reflection-Impulsivity Scale for Pre-schoolers (KRISP - Wright 1971, 1973) and on a two-choice length discrimination task were investigated. If subjects were relatively accurate on the KRISP then correct responses tended to be faster than errors while if subjects were relatively inaccurate errors were the faster. It is inferred that accurate subjects respond asymptotically in terms of a speed-accuracy tradeoff while inaccurate subjects set a less demanding criterion. Accurate subjects showed a tendency to increase inspection time as a function of item difficulty. This relation did not hold for inaccurate subjects.However, groups classified by means of the KRISP did not differ in either the speed of correct responses or accuracy of line length discriminations. For all groups judgement times were significantly related to stimulus differences and to stimulus ratios. There was no evidence that so-called impulsive children engage in less efficient and less detailed processing than other children.It is argued, contrary to the view of Kagan and his co-workers (e.g. Kakan 1966), that speed and accuracy of responding may not reflect a stable trait dimension. Rather children appear to be able to change their strategies according to the particular demands, implicit or explicit, of the task.