Error analysis of delayed response in aged squirrel monkeys

Young adult and aged squirrel monkeys were tested on variations of a two-choice, spatial delayed-response task. Aged monkeys committed more errors than did young monkeys. However, the diminished accuracy of the aged monkeys was not attributable to a memory deficiency because the difference was independent of delay interval. Aged monkeys did not display less responsesequence variability and were no more likely to commit systematic errors than were young monkeys. When response accuracy decreased as a result of increased delay intervals, or absence of a predelay cue, both age groups increased the proportion of errors attributable to random responding; however, the proportion of errors attributable to systematic errors either decreased or remained constant.     

Extraneous information in delayed pattern reproduction by monkeys

Nine highly trained rhesus monkeys were given short-term memory tests in a pattern reproduction paradigm. One white light and a variable number of red lights (1 to 15) in a 4 by 4 matrix were shown to Ss for 0.2 sec. After a 5-sec delay, Ss obtained a reward by opening the cell which previously had been illuminated with a white light. Choice of a cell which had not been illuminated or one which had been lit with a red light was not rewarded, and the response was recorded as an error. As the number of red lights increased from 2 to 6, the responses to the relevant light decreased and then, for 7 to 15 red lights, remained constant     

Learning and transposition of an extended sameness-difference concept by slow and fast learning capuchin monkeys

Capuchin monkeys were trained on a series of learning-set problems which required discrimination between stimulus arrays having ABA and BBA configurations. Transposition was later tested by presenting training configurations with CCC or ABC configurations. Considerable negative transposition and a small amount of positive transposition occurred, a result suggesting that the original learning set was based at least partly on perceived differences in the homogeneity of the ABA and BBA configurations. Fast-learning subjects manifested more persistent random responding and less position responding than did slow-learning subjects. This difference suggests that random responding during the initial stages of learning may be used as an index of attention.     

Impact of stimulus format and reward value on quantity discrimination in capuchin and squirrel monkeys

Quantity discrimination abilities are seen in a diverse range of species with similarities in performance patterns, suggesting common underlying cognitive mechanisms. However, methodological factors that impact performance make it difficult to draw broad phylogenetic comparisons of numerical cognition across studies. For example, some Old World monkeys selected a higher quantity stimulus more frequently when choosing between inedible (pebbles) than edible (food) stimuli. In Experiment 1 we presented brown capuchin (Cebus [Sapajus] paella) and squirrel monkeys (Saimiri sciureus) with the same two-choice quantity discrimination task in three different stimulus conditions: edible, inedible, and edible replaced (in which choice stimuli were food items that stood in for the same quantity of food items that were given as a reward). Unlike Old World monkeys, capuchins selected the higher quantity stimulus more in the edible condition and squirrel monkeys showed generally poor performance across all stimulus types. Performance patterns suggested that differences in subjective reward value might motivate differences in choice behavior between and within species. In Experiment 2 we manipulated the subjective reinforcement value of the reward by varying reward type and delay to reinforcement and found that delay to reinforcement had no impact on choice behavior, while increasing the value of the reward significantly improved performance by both species. The results of this study indicate that species presented with identical tasks may respond differently to methodological factors such as stimulus and reward types, resulting in significant differences in choice behavior that may lead to spurious suggestions of species differences in cognitive abilities.     

Temporal discrimination factors in the delayed matching-to-sample task in monkeys

The temporal discrimination hypothesis (TDH) of delayed matching-to-sample (DMTS) stresses the animal’s ability to discriminate which choice-stimulus alternative has appeared most recently as sample. Thus, the emphasis is placed on discriminative processes, temporal in nature, rather than on the traditional trace or buffer storage mechanisms of short-term memory. Some of the predictions of the TDH were tested within the context of the DMTS task. Experiment I showed that the difficulty of sample-stimulus sequences could be predicted by the TDH. Experiment II showed DMTS performance to be an increasing function of the number of sample stimuli employed, a result predicted by the TDH, but not by a traditional proactive interference interpretation. The results demonstrate the importance of temporal discriminative processes in DMTS. The possibility for a simpler theoretical approach to memory, in general, is discussed.

     

Sample duration and type of stimuli in delayed matching-to-sample in rhesus monkeys

Two experiments were performed to determine the effect of sample duration (0.1, 2, and 4 sec), delay interval (.03, 4, 8, 16, and 32 sec), and type of stimulus (color and shape) on the matching performance of rhesus monkeys. In Experiment 1, the 15 possible delay-duration combinations were randomly presented in blocks of 15 trials. In Experiment 2, each duration was held constant and the five delays randomly presented. Then each delay interval was held constant with the three durations randomly varied. Matching performance increased as sample duration increased (ps < .01 and .005), while length of delay did not significantly affect performance. The type of stimuli paired in the matching test significantly affected performance (ps < .05 and .10) with the shape/shape choices leading to the poorest performance. Stimulus discriminability and amount of training with brief sample durations were implicated as significant determinants of matching performance.     

Perceptual context effects on line discriminations by monkeys as measured by choice response accuracy and eye movements

Stumptailed monkeys (Macaca arctoides) were given two two-choice line-discrimination problems in which the lines were presented either alone or embedded in a patterned context that was the same in all cases. When the stimuli were a left- and a right-tilting line, the addition of the context significantly improved performance, as measured by frequency of correct choice responses. It also decreased choice response latency, duration of visual fixations, and frequency of scanning back and forth between the two stimuli. When the stimuli were a horizontal and a vertical line, the addition of the context had the opposite effect on all the performance measures. These results are very similar to those found with adult and infant humans when given the same stimuli. They suggest that the pattern perception of monkeys, like that of humans, involves top-down or holistic processing of incoming visual information.     

Retrospective and prospective short-term memory in delayed response tasks in rats

Separate groups of rats were trained and tested on asymmetrically and symmetrically reinforced successive delayed matching-to-sample (DMTS) or delayed discrimination (DD) tasks in Experiment 1. Each rat received training and testing on symmetrically reinforced DMTS and DD tasks in Experiment 2. The only difference between each task was that the rats had to respond correctly to a light or tone test stimulus, S₂, if it matched a light or tone sample stimulus, S₁, in DMTS, but could respond to either S₂ if S₁ had been a particular stimulus in DD. Only correct leverpresses were reinforced in the asymmetrically reinforced version of each task. Both correct presses and correct omissions were reinforced in the symmetrically reinforced version of each task. Response biases to leverpress during tests for delayed responding to S₁ were reduced in both symmetrically reinforced tasks, but only in the DD task did such contingencies produce consistently poorer performance in responding to either S, in Experiment 1. Declines in accuracy of performance that occurred in both experiments were greater to the visual than to the auditory S₁ only in the DMTS tasks with increased intervals between S₁ and S₂. A third experiment, in which rats had to respond to S₂ if it matched S₁ (DMTS) or if S₂ mismatched S, (DMmTS), was carried out. Modality of S₁ similarly affected accuracy of delayed responding in each task, as in the first two experiments. Methodological and theoretical implications of these results are discussed in terms of Honig and Thompson’s (1982) dual-process theory of working memory.     

Effects of sample duration and spaced repetition upon delayed matching-to-sample in monkeys (Macaca arctoides andSaimiri sciureus)

Delayed matching-to-sample was used to study the effects of sample presentation time and spaced repetition upon delayed matching accuracy in one stumptail monkey and three squirrel monkeys. It was found in Experiment 1 that presenting the sample stimulus for 0.5 sec led to lower matching accuracy than was the case with longer presentation times of 2.5, 5.0, and 10.0 sec. Experiments 2 and 3 investigated the effects of temporally spacing the presentations of the sample stimulus. It was found that spaced repetition led to a deterioration of performance relative to massed repetition. These results are similar to the findings of experiments with pigeons and are contradictory to several previous experiments with monkeys or apes which found no effect of presentation time and a facilitative effect of spaced repetition. It is suggested that the use of monkeys inexperienced in short sample duration matching and tested in operant chambers using a limited set of noncomplex stimuli may be responsible for the discrepancies between these results and those of other experiments with primates.     

动词源致歧

动词是致歧能力最强的词类,在各类歧义源中,动词源引发歧义的比重较大,因而影响也较大。多义动词项的致歧过程比较复杂,动词项也会在语义特征上显示出多重性特征;单义动词项致歧可称为语义特征致歧,其多个语义特征在句法结构中共现便可能引发歧义。     

Preference effects on acquisition and retention of concurrent discriminations by rhesus monkeys

Ten rhesus monkeys were trained on five tasks, each of which consisted of eight concurrently presented object discrimination problems. Sequences of presentation were devised to allow one, two, or three new tasks to intervene between acquisition and retention tests or to provide a 30-day period of no testing. Equivalent and proficient performances were obtained in all retention tests, and no relationship was observed between retention and the initial preference characteristics of various objects. Object pReferences did produce significant influences upon acquisition, but these effects were not as pronounced in early tasks as in later ones. An additional retention test provided support for the contention that monkeys do not necessarily process information about specific object pair discriminations. Rather, they appeared to retain a list of previously rewarded objects even when object pairings were different from those provided during acquisition. Concurrent discriminations involving many distinct objects were resistant to interference and independent of preference characteristics over long retention periods.     

Auditorysame/different concept learning by monkeys

Two rhesus monkeys learned the auditory abstract concept ofsame/different. They were trained with 38 different environmental and natural sounds, which were arranged in different combinations as training progressed. Upon transfer to 138 different novel stimuli, they performed as well (78.8% correct) on the first exposure to the novel stimuli as they did (77.3%) with their training stimuli. The comparatively large set of training sounds, contact with the sound source, and a special fading procedure are thought to have contributed to the monkeys’ being able to learn this concept. Implications for species’ similarities/differences in cognitive processing are discussed.     

过度包装产生的根源探析

商品的包装设计极大推进了人类社会文明的进步,也为商品经济的繁荣做出了巨大贡献,使人们充分享受到物质文明和精神文明的成果。但为了迎合产品生产厂家的利润需求和所谓的自身价值而不顾社会良知,过度包装、欺骗包装的屡屡出现,却已成为社会一大公害。     

指针错误辨析

指针的概念在C语言程序设计中较其它概念难以理解和掌握,在学习和使用中容易出错,因此在学习和使用中要多仔细思考,多比较,多上机调试,弄清细节,并从中积累经验,才能找出程序中的隐蔽的错误,使程序经得起考验,从而达到正确掌握和使用指针的目的。     

Examiner errors on the WRAT-R

A random sample of 55 WRAT-R protocols, completed by nine practitioners for a metropolitan school district in the South, was analyzed for examiner errors. All nine practitioners made errors, which occurred on 95% of the protocols and averaged 3.0 errors per protocol. The most frequent errors included failures to obtain a correct ceiling or basal, and failures to record examinees' responses. Correction of the examiner errors resulted in changes in 11 standard scores, and 3 additional changes in grade equivalent scores. These results indicate that WRAT-R administration and scoring are not as objective as assumed by the test developers, and that examiner errors on this test can adversely affect diagnostic decisions.     

韩国学生作文中遗漏和误加偏误类型分析

中介语理论认为,对于学习者来说,“偏误”是学习过程中的一个部分,是极其自然的现象,是不可避免的也是必需的,表明学习者正在从不会到掌握语言的过渡阶段.因此,偏误反映了语言学习的客观规律,应该正确认识并分析它.运用中介语理论对韩国学生作文中遗漏和误加两种偏误类型进行分析,初步探讨两种偏误中所反映出来的学习策略.     

Types of errors made by Papua New Guinean students

This exploratory study used an interview technique to find the frequency of different types of errors which a group of year 6, Papua New Guinean students made on a mathematics test. A further investigation was made into reading, comprehension and careless errors. Although the general trend for errors was the same for western students, some striking differences were found. In particular Papua New Guinean students made far fewer careless errors.     

Pretraining and discrimination reversal learning by rhesus monkeys

Groups of five to seven macaques were trained on repeated reversals of a visual (or spatial) discrimination habit after no pretraining, extended discrimination training, or repeated reversal training on spatial (or visual) cues. Neither sort of pretraining had a significant effect on reversal learning on the second cue. These results indicate that monkeys’ capacity to develop generalized “win-stay, lose-shift” hypotheses may have been exaggerated in previous experiments.     

Analysis of fraction errors by a model of cognitive science

In clinical interviews, grade 7 students of average abilities worked out some problems on the topic of fractions; the problems were given to the children in different forms of representation. From the examples it is illustrated that, even if children are dealing with similiar exercises and even if they had been taught in the same way, their mathematical thinking might be quite different. The differences in the children’s behavior seem to come from differences in the internal representation of their knowledge of the concepts and procedures. To explain why the children handled as they did, a theoretical framework is needed. In this paper, Davis and McKnight’s «hypothetical mechanisms» are used to explain children’s understanding of fractions. A revised version of Minsky’s and Davis’ frame-model seems to be especially useful to explain the relationship between the teacher’s notions, the children’s «concept images» and the real-world aspects of mathematics.