Maze-arm length affects a choice criterion in the radial-arm maze

Male rats were tested in a 12-arm radial maze with 6 arms that were standard in length and 6 arms that were half the standard length. As previously reported by Brown (1990), revisits to short arms were more likely than revisits to long arms. Two explanations of this effect of mazearm length on choice accuracy were experimentally contrasted. The first attributes the effect to diminished discriminability of visited and unvisited arms when the arms are short. The second attributes the effect to a relatively lax choice criterion being applied to short arms. An analysis of the microstructure of choices, applying the logic of signal detection theory, provided evidence for the latter explanation.     

Spatial memory and the performance of rats and pigeons in the radial-arm maze

The resource-distribution hypothesis states that the ability of an animal to remember the spatial location of past events is related to the typical distribution of food resources for the species. It appears to predict that Norway rats would perform better than domestic pigeons in tasks requiring spatial event memory. Pigeons, tested in an eight-arm radial maze, exhibited no more than half of the memory capacity observed in rats in the same apparatus and may not have used spatial memory at all. The results were interpreted as supporting the hypothesis.     

A “random-walk” simulation model of multiple-pattern learning in a radial-arm maze

Wathen and Roberts (1994) reported rather surprising results of a radial maze study that on any interpretation requires postulation of previously unsuspected high-level cognitive processes in rats. In each of four arms of the eight-arm radial maze, a different serial pattern unfolded over trials; for example, in one of the arms reward and nonreward alternated over successive trials. On each trial, rats came to track successfully four different patterns simultaneously. The authors suggested that rats tracked the pattern by using some form of trial-number strategy; that is, the trial number indicated which arms contained the better rewards. This strategy could involve a hypothesis, considered unlikely by some, that rats are capable of keeping track of as many as eight successive events—as, for example, by counting. A simulation model that embodies a specific form of the trial-number hypothesis is described here, and the results of the simulation correlate remarkably well with the observed data. In addition, the model makes four separate predictions that are supported by Wathen and Roberts’s data and that seem beyond the scope of other available theories.     

Social effects on spatial choice in the radial arm maze

Social memory was investigated in the context of a spatial working memory task. Pairs of rats were tested in an eight-arm radial maze. Under most conditions, there was a tendency to choose maze locations that had been visited earlier by the other rat. The possibility that this tendency is produced by common preferences for particular maze locations was ruled out. An opposite tendency to avoid visits to locations that had been visited earlier during the trial by another rat was found only when the maze location contained two pellets (rather than an undepletable supply), the rats’ ability to see each other in the maze was restricted to the central arena, and the maze location had been previously visited by the focal rat. The amount of food available in maze locations did not otherwise modulate social influences on spatial choice. The results indicate that memory for a rat’s own previous choices is combined with memory for the choices made by another rat.     

The effect of maze structure upon the performance of a multiple-goal task

Learning & Behavior - The ability of rats to find food in three kinds of mazes (radial, parallel, antiradial) was studied. Each maze had eight goalboxes. All goals were baited at the beginning...     

管路长度对箕斗定重称载液压系统动态和静态性能的影响

针对王石凹煤矿定重称载系统液压元件和管路受损严重,且系统存在响应滞后和称重不准确等问题。本文采用AMESim方法建立了定重称载液压系统的仿真模型,分析了液压管路长度对箕斗定重称载液压系统的响应速度、准确性及系统刚度等动态和静态指标的影响,结果表明:液压管道的内径恒定时,系统的超调量、调整时间、固有频率、相对误差和刚度随管道长度的增大而减小,阻尼比随管道长度的增大而增大。建议系统设计时直接测量载荷增量,并根据管道长度对系统误差的影响进行质量补偿。     

Intratrial proactive interference in rats’ serial alternation performance in the radial maze

Rats acquired a serial alternation task in an eight-arm radial maze that was partitioned into four pairs of arms. Each pair was associated with a different distal stimulus. Rats were initially forced to the left or right arm in each pair (the study segment) before being exposed to both arms in each pair (the free-choice or test segment). Only the previously blocked arm of each pair remained baited. Following initial training, proactive interference (PI) was induced by presenting rats with a forced-choice (prestudy) segment containing arm positions opposite those in the subsequent study segment. Such trials generated poorer free-choice accuracy than did trials without a prestudy segment. Forcing rats to both arms in the pair in a prestudy segment produced only transient PI. A slight improvement in rats’ free-choice performance was obtained by forcing them to the same arm position, but only when the test segment was delayed by 30 min. Increasing the interval between the prestudy and study segments from 2 to 30 min eliminated PI, but only when free-choice testing was delayed by 2 min rather than by 30 min. These results suggest that intratrial PI in this preparation was primarily due to confusion about which arm position in each pair had been visited during the last forced-choice segment.     

The effects of morphology and word length on the reading of Hebrew nominals

This article investigated the effects of twospecific Hebrew nominal word structures andword length, on the latency and accuracy ofgrade school children's reading ofwords. For this study, three-, four- and five-letterwords of the feminine nominalderivative structure and the feminine nominalinflectional structure, at three differentgrade levels, were used. The study alsodifferentiated between an additional vocalizedconsonant and the addition of a vowel letter.The participants, 150 native monolingual Hebrewspeakers in grades two, four and six, wereasked to read vocalized nouns. The paperreports and analyzes the differences in thereading of the two morphological structures andword lengths to draw conclusions about theireffects on reading performance. The resultsindicated that inflections took longer to readand elicited more correct responses thanderivations. For derivations with theprogression of grade level, latency becomesshorter and the number of correct responsesincreases. For inflections with the progressionof grade level, latency becomes longer but thenumber of correct responses increases. With theaddition of a consonant at all grade levels,latency becomes longer. For accuracy, therewere differential results for the differentword lengths in the different grades. With theaddition of a vowel letter, accuracy increasedin all the grade levels. Latency, for the twoword lengths, showed differential results inthe different grades. A hypothesis on readingdevelopment is suggested based on the language-specificcharacteristics of Hebrew morphologyand the double vowel system of Hebrew.     

内插管长度对排气抗性消声器性能的影响

提高消声器的声学性能,通常会导致空气动力性能的增大,因此要对消声器的综合性能进行评价。利用COMSOL Multiphysics和FLUENT商业软件,对某汽车排气抗性消声器的综合性能进行研究,分别对其在具有4种不同内插管长度组合情况下的声场和流场进行数值模拟,获得消声器的声压分布特性、传递损失及压力损失,并分析和研究了内插管长度对消声器声学性能和空气动力学性能的影响。模拟结果表明,随着内插管长度的增加,消声器的传递损失在低频段明显提高,且消声器的压力损失有所下降,从而汽车排气抗性消声器的综合性能得到了提高。     

The effects of new science curricula on student performance

This study summarizes the results of a quantitative synthesis of the retrievable primary research dealing with the effects of new science curricula on student performance. This study synthesizes the results of 105 experimental studies involving more than 45,000 students and utilizes the quantitative synthesis perspective to research integration known as meta-analysis (Glass, 1976). A total of 27 different new science curricula involving one or more measures of student performance are included in this meta-analysis. Data were collected for 18 a priori selected student performance measures. The results of this meta-analysis reveal definite positive patterns of student performance in new science curricula. Across all new science curricula analyzed, students exposed to new science curricula performed better than students in traditional courses in general achievement, analytic skills, process skills, and related skills (reading, mathematics, social studies and communication), as well as developing a more positive attitude toward science. On a composite basis, the average student in new science curricula exceeded the performance of 63% of the students in traditional science courses.     

The effects of sodium pentobarbital on matching and oddity performance in pigeons

The effects of sodium pentobarbital on matching and oddity performance in pigeons were examined by employing a higher-order conditional discrimination paradigm. In this paradigm, the line orientation which was superimposed on all of the response keys signaled whether a response to the matching color or a response to the nonmatching color was correct. All pigeons had extensive previous training in this paradigm and were tested at each of three dosage levels: 5, 7.5, and 10 mg/kg. For all birds, a clear dose-related decrease in accuracy was observed; however, the effect was not differential for matching and oddity trials. Accuracy reductions were accompanied by an increase in position preference on both types of trials. The data are compatible with recent claims that physical identity of the sample and correct comparison stimulus need have no special status for pigeons.     

The effects of strong irrelevant thirst on food-rewarded instrumental performance

In Experiment I, rats received one food rewarded trial per day in a runway. One group received all its trials under hunger (Group H); the second group received a random half of its trials under hunger and the other half of its trials under hunger plus thirst (Group H-HT). Group H-HT ultimately ran slower on HT trials than on H trials. In Experiment II, the effects of shifting from H to HT and vice versa were examined in a five-phase design. In general, rats run under H ran faster than rats run under HT, and shifts from H to HT produced rapid decreases in speed, while shifts from HT to H produced extremely slow increases in speed. The results of both experiments were interpreted as indicating that the reward value of food is greater under H than under HT and that the manipulation H vs. HT may be viewed as theoretically similar to manipulation of reward magnitude.     

Central-place foraging by rats on the radial maze: The effects of patch size,food distribution,and travel time

Rats foraged on a four-arm radial maze with one, two, three, and four food items (0.65.g pieces of cheese) placed on different arms (patches) of the maze. In two experiments, the hypothesis was tested that rats should carry food to the center of the maze more often when a patch contains one food item than when it contains multiple food items. Support for this prediction was found when the tendency to carry initial items encountered in patches was compared among the different sized patches. However, a further observation failed to support the hypothesis: Food carrying declined from first to last item encountered in multiple-item patches with clustered food items. Experiment 1 revealed that food carrying was reduced when travel time was increased by barriers placed at arm entrances. Both Experiments 1 and 2 indicated that the tendency for rats to carry food to the center of the radial maze increased as the distance of food encountered on an arm increased from the center. In both experiments, some rats dealt with the problem of multiple items by resorting to multiple-item loading, and some rats carried food items from the end of an arm to a point on the arm nearer the center for consumption.     

The effects of faking on non-cognitive predictors of academic performance in University students

This study examined the extent to which students could fake responses on personality and approaches to studying questionnaires, and the effects of such responding on the validity of non-cognitive measures for predicting academic performance (AP). University students produced a profile of an ‘ideal’ student using the Big-Five personality taxonomy, which yielded a stereotype with low scores for Neuroticism, and high scores for the other four traits. A sub-set of participants were allocated to a condition in which they were instructed to fake their responses as University applicants, portraying themselves as positively as possible. Scores for these participants revealed higher scores than those in a control condition on measures of deep and strategic approaches to studying, but lower scores on the surface approach variable. Conscientiousness was a significant predictor of AP in both groups, but the predictive effect of approaches to studying variables and Openness to Experience identified in the control group was lower in the group who faked their responses. Non-cognitive psychometric measures can be valid predictors of AP, but scores on these measures can be affected by instructional set. Further implications for psychometric measurement in educational settings are discussed.     

Retroactive interference in rat radial maze performance: The role of point of delay interpolation and the similarity and amount of interpolated material

The conditions necessary for producing retroactive interference (RI) were examined in a 12-arm radial maze. Rats were first given either three or nine forced choices in a to-be-remembered maze. During a 2-h delay, they received one or two trials in a second 12-arm maze, located either in a different room or the same room as the to-be-remembered maze. During the postdelay memory test, RI from the interference trials was produced only when nine choices had been made in the to-be-remembered maze and two interference trials had been conducted during the delay interval. RI was not found when only three forced choices had to be retained or after a single interference trial. The similarity between the interpolated and to-be-remembered mazes had no effect on choice accuracy. It was concluded that two conditions are required for the production of RI in the radial maze. First, a “large amount” of information should be resident in working memory. Second, a substantial number of interpolated trials or choices must be made during the delay.     

The Impact of Self-assessment on Achievement: The effects of self-assessment training on performance in external examinations

Can the quality of students' work be improved through training in self- assessment practices? This paper considers the impact of training high school students on their performance in external examinations. Teachers were selected from a sample of high schools and trained in how to develop students' self-assessment skills. Ten high schools representative of the top, middle and bottom levels of academic achievement in national examinations were chosen and students trained in self-assessment by their normal class teachers as part of their final year curriculum. An experimental group comprising 256 participants received formal training in self-assessment skills for the entire three terms of the academic year. A control group was selected from matched classes not receiving such training. A significant difference favouring those trained in self-assessment was found overall and in each curriculum area. While it is demonstrated that self-assessment training can have an impact on student performance the paper considers the circumstances of the study and whether similar outcomes might be possible in less favourable conditions.     

Test motivation in the assessment of student skills: The effects of incentives on motivation and performance

There is widespread concern that assessments which have no direct consequences for students, teachers or schools underestimate student ability, and that the extent of this underestimation increases as the students become ever more familiar with such tests. This issue is particularly relevant for international comparative studies such as the IEA’s Third International Mathematics and Science Study (TIMSS) and the OECD’s Programme for International Student Assessment (PISA). In the present experimental study, a short form of the PISA mathematical literacy test is used to explore whether the levels of test motivation and test performance observed in the context of the standard PISA assessment situation can be improved by raising the stakes of testing. The impact of (1) informational feedback, (2) grading, and (3) performance-contingent financial rewards on the personal value of performing well, perceived utility of participating in the test, intended and invested effort, task-irrelevant cognitions, and test performance are investigated. The central finding of the study is that the different treatment conditions make the various value components of test motivation equally salient. Consequently, no differences were found either with respect to intended and invested effort or to test performance.     

The effects of the kinesthetic-tactile component of the VAKT procedure on secondary LD students' reading performance

Multisensory instructional approaches have been used in teaching handicapped children for many years, but have never been adequately validated. Using a multiplebaseline design and direct measurement of words read and spelled as the dependent variable, this study evaluated the effects of the kinesthetic-tactile component in VAKT instruction. The results indicated that the three secondary LD students read more words correctly after VAKT instruction than after VA instruction, and retained more VAKT instructed words at one-week, three-week, and six-month retention probes. The instruction did not differentially affect the speiling of words. The implications of these findings are discussed.