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1.
Pigeons categorized binomial samples. One of two “coins” was tossed on each trial, and birds learned to infer from observing the outcomes which of the two equally likely coins had been tossed. Outcomes (“heads” or “tails”) appeared as successively presented red or green center keys. Coin R was biased in favor of red, and coin G was similarly biased in favor of green. A categorization consisted of a choice of a left or right side key and was reinforced with food if it was to the key (left for coin R and right for coin G) corresponding to the coin that produced that trial’s sample. Coin bias and minimum sample size required for reinforcement were experimentally manipulated. When sample size was greatest (n=8), categorizing a sample as having been produced by coin R tended to undermatch the probability that the sample was produced by coin R. When sample size was smallest (n=1), categorizing a sample overmatched, provided that the context did not include other trials with large samples. This context effect reconciles an otherwise inconsistent literature on intuitive statistical inference in pigeons but suggests a new and difficult goal for research-the general clarification of the effects of sampling context on inference. 相似文献
2.
Douglas S. Grant 《Learning & behavior》1986,14(3):267-275
Pigeons were trained in an intratrial interference preparation in which a horizontal or vertical line was presented for 1 sec immediately following termination of a sample (red or green). Two samples were presented successively on interference trials. Choice of the comparison corresponding to the second (target) sample was designated correct and was reinforced, and choice of the comparison corresponding to the first (interfering) sample was designated incorrect and was not reinforced. Control trials involved the presentation of a single, target sample. A horizontal line was presented upon termination of an interfering sample, and a vertical line was presented upon termination of a target sample. The results of three experiments led to the conclusion that the horizontal line acquired and capacity to reduce postperceptual processing (rehearsal) of information derived from an immediately preceding sample stimulus. These findings include (1) convergence of accuracy on control and interference trials as training progressed, (2) a reduction in accuracy on control and especially on interference trials when the correlation between sample type (interfering or target) and cue type (horizontal or vertical) was reduced to zero, (3) higher accuracy (i.e., less interference) when the horizontal rather than the vertical line followed the interfering sample, and (4) higher accuracy on single-sample trials when the vertical rather than the horizontal line followed sample presentation. 相似文献
3.
Thomas R. Zentall Lou M. Sherburne Janice N. Steirn Christopher K. Randall Karen L. Roper Peter J. Urcuioli 《Learning & behavior》1992,20(4):373-381
Common coding in pigeons was examined using a delayed conditional discrimination in which each sample stimulus was associated with two different comparison stimuli (one-to-many mapping). In Experiment 1, pigeons matched circle and dot samples to red and green hues and vertical and horizontal line orientations. In Experiment 2, the samples were red and green and the comparisons were vertical and horizontal spatial positions (up vs. down and left vs. right). Following acquisition to high levels of accuracy in each experiment, the associations between the samples and either both sets or only one set of comparisons were reversed. Pigeons learned the total reversals faster than the partial reversals. These results suggest that when different comparisons are associated with a common sample, they may become functionally equivalent. 相似文献
4.
Peter K. Dunn 《Teaching Statistics》2005,27(2):37-41
Rolling dice and tossing coins can still be used to teach probability even if students know (or think they know) what happens in these experiments. This article considers many simple variations of these experiments which are interesting, potentially enjoyable and challenging. Using these variations can cause students (and teachers) to think again about the statistical issues involved – and learn in the process. 相似文献
5.
论陈璧的经济思想与实践 总被引：1，自引：0，他引：1
苏全有 《河南师范大学学报(哲学社会科学版)》2006,33(2):62-66
陈璧作为清末思想性与实践性相结合的平衡型人物、中央政府的重要官员,其经济思想集中体现在三个方面:一、体恤商艰。他制订有利于当商、钱商的经济政策,取缔官方勒费的陋规,倡导官助商办,努力营造良好的金融秩序。二、重工、重农。重工思想主要是倡办工艺局,教导女工倡办纺织;重农思想集中体现为创办农务学堂。三、整顿铜币。陈璧于光绪三十二年受命出都考察各地铜币厂,在此基础上制订“划一章程十六条”,酌量归并各厂,确定铸造铜币的数目,主旨是解决各省“多铸争销之弊”。整顿铜币之余,陈璧还主张加强对与铜币紧密关联的银币、纸币等的监督管理。总之,陈璧的经济思想最集中地体现在上述三个方面,其中体恤商艰思想反映了他顺应时代潮流的改革派特征,重工、重农思想折射出其务实、进取特征,而整顿铜币则流露出加强中央集权的倾向性。 相似文献
6.
In this article, we discuss at length a combinatorial problem which has been of historic interest. It has appeared as a puzzle in several different versions with varying degrees of difficulty. It can be simply stated as follows: We are given a number of coins which are otherwise identical except that there may be at most one fake coin among them which is either slightly heavier or slightly lighter than the other genuine coins. Using only a two-pan weighing balance, we must devise a weighing scheme to identify the counterfeit coin and determine whether it is heavier or lighter (or declare that all coins are normal). We construct both sequential and non-sequential (that is, simultaneously declared) weighing plans for any given number of coins containing at most one fake coin using the minimum number of weighings needed. 相似文献
7.
Douglas S. Grant 《Learning & behavior》1982,10(1):7-14
In two matching-to-sample experiments, pigeons’ performance with samples of stimuli (red and green), number of responses (1 and 20), and reinforcers (food and no food) was assessed. Samples of red, 20 responses, and food were associated with the red comparison stimulus, and samples of green, 1 response, and no food were associated with the green comparison stimulus. On interference trials, three sample types were presented on each trial, and two of the samples (congruent) were associated with the correct comparison and the third sample (incongruent), with the incorrect comparison. Performance on interference trials was compared with that on control trials in which either two (Experiment 1) or three (Experiment 2) congruent samples were presented. It was found that presentation of an incongruent sample reduced matching accuracy markedly, and about equally, whether samples were presented successively or in compound. Although the type of sample that was incongruent was without effect, matching accuracy declined strongly as the recency of the incongruent sample increased. Serial position of the incongruent sample also influenced the shape of the retention function on interference trials. Presentation of the incongruent sample either first or second resulted in accuracy decreasing across the retention interval, whereas presentation of the incongruent sample last in the input sequence resulted in increasing accuracy across the retention interval. The theoretical implications of the findings are considered. 相似文献
8.
周玉英 《福建师范大学学报(哲学社会科学版)》2005,(5):107-111
清前期为平抑市场上铜钱价格,清政府采取如下措施:一,增加铸币量.二,增加铸铜的主要原料供应;购铜资金主要动用关税、芦、盐课税;而购铜行为又屡经变化.康熙开海后还购洋铜以弥补滇铜不足.三,处理阻碍铜钱流通中的私铸及毁钱制器等问题.随着市场铜钱量的增加,到乾隆中期以后,已改变了钱贵银贱的局面.此后,清朝政府的重心已不是平抑钱价,而改为平抑银价了. 相似文献
9.
Two pigeons matched to sample in a three-key operant conditioning chamber. In Experiment I, two different kinds of samples were presented on the center key.Element samples were members of one of two sample sets — colors (a red or blue disk) or lines (a vertical or horizontal orientation of a set of white lines). These samples were followed by their respective sample sets on the side keys as comparison stimuli.Compound samples consisted of a set of lines superimposed on a colored disk. Following these samples, either sample set could appear as comparison stimuli. Matching to compound samples was less accurate than matching to element samples. One interpretation is that sharing of attention among elements of a compound sample weakened stimulus control by each element. A different interpretation is that an element sample controlled matching better because it was physically identical to a comparison stimulus whereas a compound sample was not. Experiments II–IV evaluated this “generalization decrement” alternative by testing element- vs. compound sample control with both element and compound comparison stimuli. Irrelevant elements were added to form compound comparison stimuli, some of which were physically identical to a preceding compound sample, but never identical to an element sample. In all experiments, the addition of irrelevant elements of comparison stimuli reduced sample control. However, the generalization decrement hypothesis failed to predict how differences in performance maintained by element and compound samples were affected by different tests of sample control. Matching accuracy appeared to be independently determined by the number of elements in a sample and whether irrelevant elements were present during tests of sample control. 相似文献
10.
Angelo Santi 《Learning & behavior》1989,17(3):349-354
Pigeons were trained in a two-choice delayed matching-to-sample task with red and green hues. A brief postsample cue (a vertical or horizontal line) signaled whether the comparison stimuli would be presented or omitted on each trial. Comparison stimuli were always presented following the remember (R) cue, but never following the forget (F) cue or no-cue trials. One group of birds, the differential outcome (DO) group, received reinforcement with a probability of 1.0 for correct responses following one sample stimulus and a probability of 0.2 for correct responses following the other sample stimulus. The nondifferential outcome (NDO) group received reinforcement with a probability of 0.6 for correct responses to either stimulus. The effect of postsample cues was greater for the DO group than for the NDO group. Relative to the NDO group, the DO group displayed higher accuracy on R-cue trials and lower accuracy on F- and no-cue trials. Both tendencies contributed to the enhanced cue effectiveness obtained in the DO group. The results indicate that outcome expectancies are subject to maintenance rehearsal, which comes under the control of postsample R and F cues. They also suggest that maintenance rehearsal may be easier to sustain under DO conditions than under NDO conditions when a memory test is anticipated, but that it may be easier to terminate maintenance rehearsal under DO conditions when a memory test is not anticipated. The results are inconsistent with the assumption that the rehearsal of outcome expectancies is automatic. 相似文献
11.
As the number of independent tosses of a fair coin grows, the rates of heads and tails tend to equality. This is misinterpreted by many students as being true also for the absolute numbers of the two outcomes, which, conversely, depart unboundedly from each other in the process. Eradicating that misconception, as by coin‐tossing experiments, should be incorporated early on into learning the law of large numbers. 相似文献
12.
The effect of differential outcome expectancies on memory for temporal and nontemporal information was examined. Pigeons were trained to match short (2-sec) and long (8-sec) sample durations to red and green comparison stimuli, and vertical and horizontal lines to vertical and horizontal comparison stimuli. In Experiment 1, one differential outcome (DO) group received food for correct choices on short-sample trials, whereas another received food for correct choices on long-sample trials. On line-orientation trials, half of each DO group received food for correct responses following vertical samples, whereas the other half received food for correct responses following horizontal samples. Overall retention was greater in the DO groups than in a nondifferential (NDO) group that received either food or no food for correct responses on a random half of all trials. Furthermore, although the NDO group displayed a choose-short bias for temporal samples, both DO groups displayed equivalent biases to select the comparison stimulus associated with food. In Experiment 2, differential outcome expectancies were extinguished off-baseline. Subsequently, in the first nondifferential outcome test session, the. DO groups performed less, accurately than the NDO group. These findings indicate that temporal samples are not retrospectively and analogically coded when they are differentially associated with food and no food. Instead, they are remembered in terms of the corresponding outcome expectancies. 相似文献
13.
赵善轩 《江西师范大学学报(哲学社会科学版)》2010,43(1):70-73
著名历史学家全汉升认为＂中古自然经济＂是自汉魏以后开始出现的,可是种种迹象显示,自然经济化情况在两汉之际已开始出现。两汉俸给由西汉时以钱币为主转变为东汉时的半钱半谷,汉晋以后则发展为以实物支付为主的模式,可见,中古自然经济的发展有其历史渊源,而战争及币材不足只是当中较表面的原因,更重要的可能是受到当时货币思想倒退,甚至出现反货币思想的影响。 相似文献
14.
Performance during simultaneous matching-to-sample was assessed in pigeons presented with element and compound visual samples. In Experiment 1, pigeons were trained with a symbolic matching procedure, in which different pairs of colored comparison cues presented on side keys were mapped onto a bright or dim houselight as one pair of sample stimuli and onto vertical and horizontal lines on the center key as a second pair of sample stimuli. They were then tested with houselight-line compound samples. It was found that matching accuracy for lines was significantly diminished with compound samples relative to element samples. Conversely, house-light intensities were matched as well with compound samples as with element samples. In Experiment 2, a similar effect was found with pigeons that had been trained to match only line samples. In Experiment 3, it was discovered that sample duration had no influence on the matching deficit found with lines following compound samples in birds either trained or not trained to match houselight intensities. These results, taken in combination with recent findings from experiments with auditory-visual compounds, suggest a restricted processing account of pigeon processing of simultaneously presented stimuli from different sources. 相似文献
15.
在海南出土的钱币中,最早的是“半两”钱。自宋代开始,海南社会经济的发展在大量移民进入、生产技术和生产力显著提高、海外贸易空前发展的推动下,进入到一个真正的全面开发时期,使得货币在一定的范围和领域得到使用和流通。两宋时期的货币在海南各地大量出土便是佐证之一。宋代以前的钱币在海南只是作为一种财富贮藏手段,而真正发挥货币的价值尺度、流通和支付手段应始于宋代。 相似文献
16.
Research on adolescent problem solving was extended into the domain of statistical reasoning and potential biases in reasoning. In Experiment 1, adolescents solved everyday reasoning problems dealing with the "law of large numbers" and the "intuitive analysis of covariance." In each problem, evidence was presented that portrayed each participant's dominant career goal favorably or unfavorably. In Experiment 2, adolescents and young adults were presented "law of large numbers" evidence that was goal-threatening, goal-enhancing, or goal-neutral. In both experiments, statistical reasoning could be used to discredit the evidence. Results indicated that (1) adolescents and young adults found goal-enhancing evidence more convincing than goal-neutral evidence which, in turn, was perceived more favorably than goal-threatening evidence; (2) statistical reasoning was more frequent on goal-threatening problems than on goal-neutral and goal-enhancing problems; (3) intellectual ability was unrelated to the biases in adolescents' reasoning; (4) verbal ability was linked to "law of large numbers" reasoning, but no cognitive ability was systematically correlated with "analysis of covariance" reasoning; and (5) law of large numbers reasoning of young adults was superior to that of adolescents, but young adults were no less biased in their reasoning than adolescents. The potential functions and consequences of adolescents' biased reasoning, the relation of everyday reasoning to general intellectual abilities, and the influences of motivation and depth of processing are discussed. 相似文献
17.
Oliver and Soundararajan have recently discovered an unexpected bias in the distribution of prime numbers. Interestingly, the authors embarked on this research after hearing about a counter-intuitive result obtained upon comparison of two elementary coin tossing experiments. This article describes these experiments and presents both numerical and analytical methods for exploring the source of inspiration for their research. Elaboration of such key motivations or themes provides a way of bringing the excitement of recent mathematical discoveries to the undergraduate classroom. 相似文献
18.
B. V. Rao 《Resonance》2011,16(1):12-28
Even elementary probability has a lot of interesting things to offer to the students to get excited and think about. Unfortunately
our curricula are generally designed in such a way that interesting things are carefully left out. Even if the material is
touched upon briefly, the discussion is reduced to simple calculation of ratios devoid of any meaning. In this article we
discuss two interesting models in probability. We just throw balls into boxes as dictated by tossing coins, nothing more than
that. 相似文献
19.
李辉 《兰州石化职业技术学院学报》2008,8(3):78-80
随机变量的统计规律是一个复杂的概念。通过对典型实例的分析研究,揭示出一维离散型随机变量的形成过程及其变化规律。具体描述了样本点与随机变量之间的对应关系及事件与随机变量取值之间的等价关系,得出掷硬币正面出现的“总次数”近似服从正态分布,据此可刻划“掷硬币正面出现”这一随机现象的统计规律性． 相似文献
20.
Rickey E. Carter 《Teaching Statistics》2013,35(3):127-130
Assuming a coin is fair is common place in introductory statistical education. This article offers three approaches to test if a coin is fair. The approaches lend themselves to straightforward simulation studies that can enrich student understanding of joint probability and sample size requirements. Simulation studies comparing the relative merits of the three, or potential other, approaches are an example of problem‐based learning. 相似文献