首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
A patient with developmental Gerstmann syndrome who experiences great difficulty in performing tasks requiring visuoconstructive and reading abilities is described. Neuropsychological assessment revealed normal range verbal abilities but severe deficits in directional orientation, finger differentiation, calculational ability, copying, and reading ability. Achievement in reading was measured at the sixth-grade level despite the fact that this patient is a third-year college student. Using infrared photoelectric sensors, we monitored the horizontal saccades of this patient while reading from a standardized reading test. Fixation durations were not abnormal. However, instances of reverse-staircase movement were exhibited. While reading from an inverted test, she showed a normal eye-movement pattern (although in the reverse direction since the task now called for right-to-left saccades). The processing of spatial information in this patient is severely disturbed and this may account for the apparently abnormal oculomotor scanning, an “irrepressible tendency” to move her eyes in a right-to-left direction.  相似文献   

2.
In the first experiment rats were given either 16 or 48 nonrewarded or continuously rewarded trials prior to 24 continuously or partially rewarded trials, followed by extinction. Increased resistance to extinction was found for increasing numbers of nonrewarded trials when they were followed by partial reward, but not when followed by continuous reward. Similarly, more continuously rewarded trials followed by partial reward tended to increase resistance to extinction. Because of the theoretical importance of the effect of continuous reward followed by partial, a second experiment was performed where the range of the number of continuously rewarded trials was extended to 0, 48, and 96. Contrary to many theoretical predictions, resistance to extinction increased as a function of increasing amounts of continuous reward.  相似文献   

3.
Rats received either partial reward (PR) or partial delay (PD) in acquisition with one, two, or three delay or nonreward trials followed by an immediately rewarded trial or one delay or nonreward trial followed by an immediately rewarded trial. These four groups were then split in half and given either continuous delay or continuous nonreward (extinction) in a “response persistence” phase. In addition, two continuously reinforced groups, one experiencing continuous delay, and the other experiencing extinction were included. The results showed that response persistence was greater when PD groups were given continuous delay rather than extinction, but the opposite was true for PR groups. The “length” (1, 2, or 3 versus 1 nonreward or delay trial) also transferred to the response persistence phase with the length 1, 2, and 3 conditions being more persistent than the 1 length conditions. The results were discussed with respect to theoretical notions of response persistence.  相似文献   

4.
In the first experiment rats experienced large or small magnitude of negative reinforcement (shock reduction) in a straight alley. Half of the subjects in each magnitude group received continuous reinforcement, and the other half received a 50% partial reinforcement schedule (nonreinforcement consisting of no shock reduction in the goal box). In extinction the groups were ordered: large partial > small-partial > small-continuous > large-continuous. In the second experiment rats received large, small and nonreinforcement in various sequences using the runway-negative reinforcement procedure and were ordered: SNL>LNL>SNL>LNS in resistance to extinction (letters represent the magnitudes in the sequence experienced in acquisition). The results of these experiments indicate a commality between positive and negative reinforcement with respect to behavioral phenomena and theoretical accounts of those phenomena.  相似文献   

5.
Six experiments with rat subjects investigated the role of conditioning in morphine tolerance. Concurrent assessments of body temperature and pain sensitivity were conducted. Experience with morphine produced tolerance to its analgesic effects but enhancement of its hyperthermic effects. Environmental novelty enhanced analgesia but not body temperature (Experiments 1 and 4). Under conditions in which a discriminated hyperthermic CR provided clear evidence that morphine-environment learning had developed, discriminated analgesic tolerance was not obtained (Experiments 2 and 3). Similarly, whereas placebo administrations extinguished the hyperthermic CR (Experiments 4 and 6), analgesic tolerance remained unaffected (Experiments 4, 5, and 6). These experiments suggest that the pyretic and analgesic systems are differentially sensitive to conditioning and the effects of novelty.  相似文献   

6.
A nonselective model postulating intrinsic cue dominance was tested in simultaneous discrimination tasks involving reversal on one dimension. In this procedure two dimensions are relevant throughout training; however, following initial discrimination training the reward contingency is reversed for one dimension but maintained for the other. Cue dominance was assessed following acquisition of reversal by the use of opposed-cues test trials, and was defined as a greater number of choices of the test compound containing the positive cue of the reversed dimension than of the test compound containing the positive cue of the maintained dimension. In Experiment I, brightness cues dominated orientation cues. In Experiment II, which employed two different sets of relevant cues, more disparate brightness cues dominated the orientation cues for one set and orientation cues dominated less disparate brightness cues for the other. From this, it was concluded that dominance is a function of relative cue similarity.  相似文献   

7.
Two experiments measured changes in binocular eye alignment from 1- to 6-month-old human infants. In Experiment 1 changes in binocular eye alignment were recorded from 1, 2, and 3 month olds using corneal photography. A luminous target was moved along the infant's midline at one of two constant speeds. Infants at all three ages showed some evidence of appropriate changes in binocular eye alignment (convergence as the target approached and divergence as the target receded). The likelihood of appropriate convergence and divergence increased with age, as did the ability to respond appropriately to the faster target motion. A measure of convergence lag (further decrease in interpupillary distance after target motion had ended) was obtained for trials on which the target approached the infant. Convergence lag decreased with age and was greater on trials at the faster target speed until 3 months of age. Experiment 2 measured the responses of 3, 412, and 6 month olds as a wedge prism was placed alternately in front of each eye. The prism displaced the image nasally (either 2.5° or 5°), creating inappropriate binocular eye alignment. A refixation eye movement in response to the prism was not present consistently until 6 months of age. Hypotheses as to the mechanism controlling infant binocular eye alignment are discussed with respect both to the present findings and to findings from human adults and animals.  相似文献   

8.
The familiarization/novelty preference paradigm was employed to study the effect of a delay (between the end of the familiarization phase and the beginning of the test phase) on discrimination of the orientation of square-wave gratings by 2- and 3-month-old human infants. Three stimulus pairs were studied: horizontal-vertical, non-mirror-image obliques, and mirror-image obliques. The data indicate that the members of the oblique-oblique stimulus pairs are confused in memory to a greater extent than the members of the horizontal-vertical stimulus pair. These findings are consistent with P.C. Bomba's (1984, Journal of Experimental Child Psychology, 37, 609-636) recent report that infants respond to the orientation of a visual stimulus in a categorical-like manner.  相似文献   

9.
In a test of the analytic-holistic theory of hemispheric asymmetry, 20 subjects saw brief presentations of upper-case letters in either the left or right visual half-field. A right half-field advantage was found for both accuracy of identification and vocal latency of erroneous responses. Multidimensional scaling, hierarchical clustering, and correlation analyses of the error patterns indicated similarities of processing between the hemispheres. The results were discussed in terms of loss of information from storage prior to processing.  相似文献   

10.
Four experiments were conducted that examine the affective and informational determinants of risk-preference behavior. In the initial two experiments, subjects classified according to their level of achievement needs expressed a preference among tasks varying in difficulty. In two of the experimental conditions, instructions, respectively, conveyed that performance at the task chosen should either maximize satisfaction or the information gained about one's ability and effort expenditure. It was found that the majority of all subjects preferred to undertake tasks of intermediate difficulty and that both positive affect and information gain were perceived to be optimal at or near the level of intermediate difficulty. Experiments III and IV investigated at what level of task difficulty individuals most desire information about their performance. Police trainees and high school students with disparate self-concepts of respective target shooting and high-jumping ability were able to receive limited but self-selected performance feedback at a series of achievement tasks that varied in difficulty. The data revealed that the tasks selected for feedback became objectively less difficult as the self-perception of ability decreased. In addition, the tasks chosen for feedback were near the intermediate subjective certainty of success level for all subjects. It was contended that the data contradict Atkinson's model of choice but support an attributional conception. The general issue of affective versus informational models of motivation was discussed.  相似文献   

11.
The pigeon's keypeck was investigated in a variety of multiple schedules of response-independent or -dependent reinforcement. Experiments 1 and 2 found that keypecking developed to a reinforcement-associated cue that signaled an increase in local rate of reinforcement, but signaled either no change or a decrease in the overall rate of reinforcement, defined as that prevailing in the cue's absence. In Experiment 3 a greater rate of responding to a target stimulus was observed when it was preceded by a second signal—associated with the same, or a lower, rate of reinforcement—and followed by extinction than when this temporal sequence was reversed. In Experiment 4 responding to a target cue increased when either a temporally prior or a subsequent reinforcement-associated cue was changed to signal extinction. Experiment 5 examined the conditioned reinforcing effectiveness of target cues in two types of situations varying the local context of reinforcement. Stimuli associated with selected target components of a response-dependent multiple schedule of reinforcement could appear as the terminal-link consequences in a two-link chain schedule. Enhanced responding during a target cue which accompanied the introduction of an extinction period following this cue was paralleled by an increase in the conditioned reinforcement effects of this cue. No such increase was found for target cues in which an enhancement of responding had been produced by the interposition of an extinction period prior to the cue.  相似文献   

12.
We argued that parental identification should be viewed as an intermediate variable which mediates the impact of parental characteristics on women's career orientation but does not directly affect career orientation itself. Questionnaire data from 457 college women showed that, while there was no overall association between career orientation and parental identification, these variables interacted significantly in their association with self-differentiation from the father, maternal employment and occupation, and maternal sex role ideology. As predicted, career orientation among mother-identified women was associated with more extensive maternal employment and less conventional sex role ideology in both parents. For this group it was also associated with greater dissimilarity between perception of self and father. For father-identified women, we hypothesized that career orientation would be associated with less dissimilarity between self and father, less extensive maternal employment, and greater maternal sex role traditionality. Results directionally supported this father-identified pattern.  相似文献   

13.
The present study compared the effects of modeling, verbal cues, and reinforcement on conceptual learning of normals and retardates. Performance on both original learning tasks and a transfer task was examined. The results indicated that, relative to a control group, modeling alone, modeling plus verbal cues, and exposure to the completed task plus verbal cues facilitated original conceptual learning. Furthermore, modeling plus verbal cues was more effective in reducing errors than modeling alone. Original learning was not affected by tangible reinforcement, social reinforcement, or IQ level. No significant effects were found for a transfer task.  相似文献   

14.
Form and function in early communication: language and pointing gestures   总被引:2,自引:0,他引:2  
Pointing gestures of verbally advanced 2-year-olds were contrasted with those of less advanced peers, in order to examine the relationships of gesture to language during the acquisition of each. Hypotheses regarding the replacement of gestural functions by speech as verbal skills improve, regarding developmental correspondences between the two communicative domains, and regarding the independence of language acquisition from nonverbal developments were drawn from evolutionary, structuralist, and nativist viewpoints, respectively. Both formal and functional aspects of each communicative skill were measured, and were shown to be largely unrelated, particularly in the gestural domain. No evidence that language replaced gesture for communication in ontogeny was obtained. Correspondences between gesture and language occurred only between functional aspects of each, and the independence of developing language from gestural advances was suggested by the findings.  相似文献   

15.
Recent research has indicated that infants are capable of responding to stimuli in a manner indicating that they categorize them. Infant perception of orientation was examined within a framework of categorization. In one experiment, it was shown that 4-month-old infants generalized habituation from one range of oblique grating stimuli to another, consistent with the interpretation that any two oblique stimuli were perceived as more similar than a vertical and an oblique. Four-month-old infants' generalization was not due to a simple inability to discriminate between obliques (Experiment 2) so the results of Experiment 1 reflect in large part true categorization behavior and not categorical perception. Results for 2- and 3-month old infants suggest that "vertical" serves as a reference stimulus in infant orientation perception such that gross distinctions between vertical and nonvertical precede the development of the "oblique" category. The category boundary between oblique and vertical did not successfully predict better between-than within-category discrimination in 4-month-old infants (Experiment 3) under the conditions of these experiments.  相似文献   

16.
It is commonly believed that age differences in memory are due primarily to input processes and secondarily, if at all, to retention processes. The present study examined this belief with a test-retest paradigm, varying rehearsal conditions orthogonal to age (first- and second-graders vs. college students). Large age effects were found for both original learning and retention, and these effects were independent of rehearsal conditions. An estimate of the relative magnitude of each suggested that age effects on retention were about half as large as age effects on original learning (e.g., input).  相似文献   

17.
Four experiments examined the conceptual organization of narrative passages and the extent to which these representations were explanatory in a variety of experimental tasks. The conceptual representation of a passage consisted of a graph of labeled nodes and labeled, directed arcs which were adopted from the Conceptual Dependency Theory. These representations included both explicitly stated information and inferences which had been empirically extracted by a question-answering procedure. Symbolic procedures for answering how- and why-questions were also delineated. The conceptual representations and the symbolic procedures that operate on these representations together accounted for 91% of the answers generated from question-answering protocols in Experiment 1, and also the rated quality of specific answers to specific questions in Experiment 2. Experiments 3 and 4 supported the hypothesis that structural properties of the representations can predict recall of explicitly stated nodes and verification ratings of inference nodes. The results provide encouraging support for the proposed graphic representations and also for the use of question-answering protocols in uncovering prose inferences.  相似文献   

18.
19.
This study examined the effects of a subject's sex and affiliative tendency and the other's physical attractiveness on the cross-sexual interaction of strangers. Although previous studies showed that one's interest in an opposite-sexed other is a function of the other's physical attractiveness, the actual behavior of individuals in the presence of attractive and unattractive others had not been systematically examined. Subjects were individually placed in a 5-min waiting situation with a physically attractive or unattractive target of the opposite sex who behaved in a standard way. Conversations were recorded and subsequently analyzed; subjects also provided their impressions of the targets following the waiting period. Physical attractiveness of the opposite-sexed other did not significantly influence the subject's verbal affiliative behavior, but the combined influence of a subject's sex and affiliative tendency was predictive of cross-sexual affiliation. Although physical attractiveness did not account for differences in affiliative behavior, subjects preferred attractive over unattractive targets as potential dates or marriage partners.  相似文献   

20.
A series of experiments investigated the effects of required force and number of responses per reinforcer upon the subsequent performance of a second behavior. In the first experiment, a group of rats required to complete five round trips in an alley per food pellet subsequently bar-pressed for food at a greater rate than a group rewarded for each round trip or a control group that did not receive the alley experience. In the second experiment, a group required to apply a 70-g bar-press force subsequently shuttled for food at a greater rate than a group required merely to touch the lever or a control group that did not undergo the lever-press manipulation. The third experiment found that the force effect persisted across all five test sessions and was attributable to differences both in response speed and interresponse time. The fourth experiment found that both the necessary bar-press force and number of bar presses per reward affected subsequent shuttling in extinction. Two alternative interpretations of these results were compared: (a) the degree of accustomed effort per reinforcer becomes a generalized component of instrumental behavior or (b) high effort increases the habituation frustration-produced disruptive responses.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号