A comparison of multiple versus single examples of the correct stimulus on task acquisition and generalization by persons with developmental disabilities

In teaching discriminations to persons with retardation, we often presume we will improve acquisition and generalization if we use multiple examples of boththe correct and incorrect stimuli. Two experiments were conducted to test this hypothesis. In the first experiment, 7 persons with moderate retardation learned to discriminate between functional words under two conditions. In one condition, Multiple Example of S- Only,1 example of the correct stimulus (S+) and 10 examples of the incorrect stimulus (S-) were used during acquisition. In the other condition, Multiple Examples of S+ and S-,10 examples of the S+ and 10 examples of the S- were used. Results showed that the condition which presented only a single example of S+ was superior 16 times and inferior 4 times during acquisition, generalization, and maintenance. A second experiment was conducted to (a) replicate the methodology and procedures in Experiment 1 with different participants, (b) determine whether the results were replicable, and (c) obtain efficiency data. Results replicated the findings of the first experiment. The condition which presented only a single example of S+ was superior on measures of (a) trials to criterion, (b) percent correct during acquisition, and (c) minutes to criterion. On measures of generalization, the two conditions were relatively equal. Thus, the condition which presented only a single example of the correct stimulus was more efficient and was just as effective in generalization as the condition which presented multiple examples of both the S+ and S-. These surprising results were discussed in terms of stimulus control, why students performed just as well during generalization when only one example of the S+ was used, why acquisition was also poorer for this condition, and how future studies might address these points.     

How Experts Adapt Their Gaze Behavior When Modeling a Task to Novices

Domain experts regularly teach novice students how to perform a task. This often requires them to adjust their behavior to the less knowledgeable audience and, hence, to behave in a more didactic manner. Eye movement modeling examples (EMMEs) are a contemporary educational tool for displaying experts’ (natural or didactic) problem-solving behavior as well as their eye movements to learners. While research on expert-novice communication mainly focused on experts’ changes in explicit, verbal communication behavior, it is as yet unclear whether and how exactly experts adjust their nonverbal behavior. This study first investigated whether and how experts change their eye movements and mouse clicks (that are displayed in EMMEs) when they perform a task naturally versus teach a task didactically. Programming experts and novices initially debugged short computer codes in a natural manner. We first characterized experts’ natural problem-solving behavior by contrasting it with that of novices. Then, we explored the changes in experts’ behavior when being subsequently instructed to model their task solution didactically. Experts became more similar to novices on measures associated with experts’ automatized processes (i.e., shorter fixation durations, fewer transitions between code and output per click on the run button when behaving didactically). This adaptation might make it easier for novices to follow or imitate the expert behavior. In contrast, experts became less similar to novices for measures associated with more strategic behavior (i.e., code reading linearity, clicks on run button) when behaving didactically.     

Examples,practice problems,or both? Effects on motivation and learning in shorter and longer sequences

Research suggests some sequences of examples and problems (i.e., EE, EP) are more effective (higher test performance) and efficient (attained with equal/less mental effort) than others (PP, sometimes also PE). Recent findings suggest this is due to motivational variables (i.e., self-efficacy), but did not test this during the training phase. Moreover, prior research used only short task sequences. Therefore, we investigated effects on motivational variables, effectiveness, and efficiency in a short (Experiment 1; four learning tasks; n = 157) and longer task sequence (Experiment 2; eight learning tasks; n = 105). With short sequences, all example conditions were more effective, efficient, and motivating than PP. With longer sequences, all example conditions were more motivating and efficient than PP, but only EE was more effective than PP. Moreover, EE was most efficient during training, regardless of sequence length. These results suggest that example study (only) is more effective, efficient, and more motivating than PP.     

A Test of the Testing Effect: Acquiring Problem‐Solving Skills From Worked Examples

The “testing effect” refers to the finding that after an initial study opportunity, testing is more effective for long‐term retention than restudying. The testing effect seems robust and is a finding from the field of cognitive science that has important implications for education. However, it is unclear whether this effect also applies to the acquisition of problem‐solving skills, which is important to establish given the key role problem solving plays in, for instance, math and science education. Worked examples are an effective and efficient way of acquiring problem‐solving skills. Forty students either only studied worked examples (SSSS) or engaged in testing after studying an example by solving an isomorphic problem (STST). Surprisingly, results showed equal performance in both conditions on an immediate retention test after 5 min, but the SSSS condition outperformed the STST condition on a delayed retention test after 1 week. These findings suggest the testing effect might not apply to acquiring problem‐solving skills from worked examples.     

Satisfiability Decay along Conjunctions of Pseudo-Random Clauses

k-SAT is a fundamental constraint satisfaction problem. It involvesS(m), the satisfaction set of the conjunction of m clauses,each clause a disjunction of k literals. The problem has manytheoretical, algorithmic and practical aspects. When the clauses are chosen at random it is anticipated (butnot fully proven) that, as the density parameter m/n (n thenumber of variables) grows, the transition of S(m) to beingempty, is abrupt: It has a "sharp threshold", with probability1 – o(1). In this article we replace the random ensemble analysis by apseudo-random one: Derive the decay rule for individual sequencesof clauses, subject to combinatorial conditions, which in turnhold with probability 1 – o(1). This is carried out under the big relaxation that k is not constantbut k = log n , or even r log log n . Then the decay of S isslow, "near-perfect" (like a radioactive decay), which entailssharp thresholds for the transition-time of S below any givenlevel, down to S = .     

以象解筮的探索——论尚秉和先生对《左传》《国语》筮例的阐解

《左传》《国语》中的筮例,是对《易》学研究极具价值的材料,历代学者对此进行过许多研究考辨、阐释解说。近代《易》学大师尚秉和先生既以《左传》《国语》筮例作为创立“尚氏学”的最重要的佐证材料之一,又将“以象解《易》”的方法用以阐解《左传》《国语》的筮例,颇具特色。本文考察了尚先生以象解筮的具体内容,辨析了“尚氏说”的自洽性,并就“尚氏说”中“观象”与“用象”、“易理”与“义理”等问题进行追问与思考。     

Advances in designing instruction based on examples

This commentary reviews the evidence for nine principles for how to design effective example-based instruction, drawing from the articles in this special issue.     

Professional responsibility: Focusing on the exemplary

The literature on ethics in science and engineering tends to dwell on the negative, emphasizing disasters, scandals, and problems of wrongdoing in everyday practice. This paper shifts to the positive, focusing on the exemplary. After outlining different possible conceptions of responsibility (ranging from a minimalist view of “staying out of trouble” to “going above and beyond the call of duty”), the paper discusses the importance of certain virtues for scientists and engineers. Finally, a broad range of examples of exemplary practice is offered. An earlier version of this paper was presented by the author at a mini-conference, Practicing and Teaching Ethics in Engineering and Computing, held during the Sixth Annual Meeting of the Association for Practical and Professional Ethics, Washington, D.C., March 8–9, 1997. This paper is one of a series edited by Michael C. Loui. See Volume 3, No. 4, 1997 for other papers in this series. Work on this paper was supported by National Science Foundation Grant #SBR-930257.     

小学生"去括号"运算规则的样例学习

为了考察小学生样例学习能力的发展和完整与不完整样例以及样例分类作业对样例学习效果的影响,作者采用完整和不完整样例以及"不完整样例-分类"三种学习作业,对270名3-5年级小学生学习"去括号"运算规则的效果进行了实验研究.结果表明:小学生"去括号"运算规则样例学习的能力随年级的增长而提高;样例分类作业对小学生学习"去括号"运算规则具有促进作用;不同类型的样例对学习不同难度的"去括号"运算规则的学习效果不同.     

中国城市农民工子女心理健康研究述评

城市农民工子女是指户籍身份还是农民, 有承包土地, 但主要从事非农产业、以工资为主要收入来源的进城务工人员的子女, 他们一般为6~18周岁的适龄上学儿童少年。中国城市农民工子女心理健康的总体水平低于城市当地儿童, 社会认知方面存在着一定的歧视知觉、相对剥夺感和身份认同危机, 情绪情感方面表现为情绪不平衡、孤独(抑郁)倾向较强和自卑(自责)心理严重, 社会适应方面显示出社会适应不良、人际关系紧张与敏感、学习适应性较差和问题行为较多。性别、年龄、人格、应对方式、生活满意度等个体因素以及家庭、学校、社会等环境因素是其心理健康水平的主要影响因素。而关于城市农民工子女的教育干预还没有形成系统, 主要是一些质性的研究。今后研究的重点应包括研究对象与内容的拓宽、研究方法的改进与完善及系统研究和理论建构的加强等。