Concurrent ratio schedules: Fixed vs. variable response requirements

Rats were trained on concurrent fixed-ratio variable-ratio or concurrent fixed-ratio mixed-ratio schedules of food reinforcement. The variable-ratio schedule was composed of an arithmetic sequence of 11 ratios that averaged 50; the mixed-ratio schedule consisted of equiprobable ratios of 1 and 99. Fixed-ratio values, varied over experimental conditions, included 25, 35, 50, 60, and 99. The proportion of responses and time allocated to the variable- or mixed-ratio schedule increased as the size of the fixed ratio increased. For most subjects, higher proportions of responses and time were maintained on the fixed-ratio schedule at fixed-ratio values of 25 and 35; higher proportions of responses and time were maintained on the variable- or mixed-ratio schedule at fixed-ratio values of 50 or higher. On concurrent variable-ratio fixed-ratio schedules, the tendency for responding to be maintained exclusively by one schedule was related to the difference in local reinforcement rates obtained from those schedules. Exclusive responding was approximated when the difference in local reinforcement rates obtained from those schedules was large; responding was more evenly distributed between the schedules as the difference in the rates at which reinforcement was obtained from each decreased.     

Local response-rate constancy on concurrent variable-interval schedules of reinforcement

Concurrent variable-interval schedules were arranged with a main key that alternated in color and schedule assignment, along with a changeover key on which a small fixed ratio was required to changeover. Acceptable matching was observed with pigeons in two replications, but there was a tendency toward overmatching. Local response rates were found to differ for unequal schedules of a concurrent pair: local response rate was greater for the variable-interval schedule with the smaller average interreinforcement interval, but qualifications based on an interresponse-time analysis were discussed. In a second experiment, two 3-minute variable-interval schedules were arranged concurrently, and the experimental variable was the changeover procedure: either a changeover delay was incurred by each changeover or a small fixed ratio on a changeover key was required to complete a changeover. Changeover delays of 2 and 5 seconds were compared with a fixed-ratio changeover of five responses. The response output on the main key (associated with the variable-interval schedules) was greater when a changeover delay was arranged than when a fixed ratio was required to changeover. A detailed analysis of stripchart records showed that a 2-second delay generated an increased response rate for 3 seconds after a changeover, while the fixed-ratio requirement generated an increased rate during the first second only, followed by a depressed response rate for 2 seconds.     

When are item response models consistent with observed data?

The problem of deciding whether a set of mental test data is consistent with any one of a large class of item response models is considered. The classical assumption of locla independence is weakened to a new condition, local nonnegative dependence (LND). Necessary and sufficient conditions are derived for a LND item response model to fit a set of data. This leads to a condition that a set of data must satisfy if it is to be representable by any item response model that assumes both local independence and monotone item characteristic curves. An example is given to show that LND is strictly weaker than local independence. Thus rejection of LND models implies rejection of all item response models that assume local independence for a given set of data.This research was supported in part by Grant NIE-G-78-0157 to ETS from the NIE, by the Program Statistics Research Project, and by TOEFL Program Research. I would like to thank Dr. Douglas Jones of ETS for stimulating discussions during the early stages of this research, Dr. Frederick Lord of ETS for his encouragement of this work and comments on earlier drafts of this paper and Professor Robert Berk of Rutgers University for pointing out that conditions (a), (b) and (c) of Theorem 2 were also sufficient for LND and Monotonicity. Dr. Donald Alderman of ETS provided financial support for the development of a computer program to apply these results to data from the TOEFL program.     

Attentional demands and recall of verbal and color information in action events

Two experiments addressed the influence of secondary task performance at encoding on recall of different features of subject-performed tasks (SPTs) involving objects (e.g., turn the wallet). In Experiment 1, memory for verbs and colors of objects was assessed, with object names serving as cues. In Experiment 2, object and color memory were assessed, with verbs serving as cues. Results from both experiments indicated a greater deterioration of memory performance under divided attention for verbal features than for colors. In addition, intention to remember did not affect performance for any feature in either experiment. The overall pattern of outcome is discussed relative to the view that encoding of verbal features of SPTs is more attention-demanding than encoding of physical task features, such as color.     

Local homogeneity in latent trait models. A characterization of the homogeneous monotone irt model

The stochastic subject formulation of latent trait models contends that, within a given subject, the event of obtaining a certain response pattern may be probabilistic. Ordinary latent trait models do not imply that these within-subject probabilities are identical to the conditional probabilities specified by the model. The latter condition is called local homogeneity. It is shown that local homgeneity is equivalent to subpopulation invariance of the model. In case of the monotone IRT model, local homogeneity implies absence of item bias, absence of item specific traits, and the possibility to join overlapping subtests. The following characterization theorem is proved: the homogeneous monotone IRT model holds for a finite or countable item pool if and only if the pool is experimentally independent and pairwise nonnegative association holds in every positive subpopulation.This research was supported by the Dutch Interuniversity Graduate School of Psychometrics and Sociometrics. The authors wish to thank two reviewers for their thorough comments.     

Knowledge and knowledge gaps in semantic memory of technical artifacts

Two hypotheses have been considered regarding the relation between knowledge and semantic knowledge gaps: a “knowledge clash” hypothesis predicting more awareness of knowledge gaps with increasing knowledge, and a “knowledge deficit” hypothesis whereby the relation is the opposite. In order to examine these hypotheses, graduate and undergraduate students were asked to state what they knew and what they did not know about a sample of familiar and unfamiliar artifacts. None of the above hypotheses accounted for the results. Instead, knowledge was found to be differently related to various types of unknown features: increasing knowledge was related to less unknown features of the artifacts' function and to more unknown features about contingency relations. Unknown features of the artifacts’ behaviors were frequently reported in the two knowledge conditions. The results suggest new strands of research on the metacognition of “not knowing.”     

学龄儿童汉语正字法意识发展的研究

该研究以小学一年级、三年级、五年级儿童及大学生为被试,让他们对左右、上下和半包围三种结构类型的９０个真字、假字和非字进行词汇判断,以探讨儿童正字法意识的发展,结构类型的相应影响,以及年龄对汉字识别中结构类型效应的作用。结果表明;（１）儿童正字法意识的形成是以识字为基础的逐步发展的过程。小学一年级儿童已萌发了正字法意识,但至五年级时才基本达到了成人水平。（２）只有小学一年级被试的真字识别受结构类型影响。汉字识别中是否存在结构类型效应可能与被试识字经验、材料熟悉性等因素有关．（３）年级内部正字法意识的萌发和年级之间正字法意识发展的差异不受结构类型的影响,但萌发之后各年级内部均是对左右结构汉字正字法意识优于上下结构和半包围结构。     

嫉妒研究的现状、特点和趋势分析

根据1981-1998年国际心理学领域关于嫉妒研究的论著,从理论和实证角度对当代嫉妒研究成果进行分类研究,旨在阐明国际嫉妒研究的现状,分析和概括其研究特点和发展趋势.     

高创造力个体的群体差异性研究

高创造力群体的界定是创造力研究的重要前提,但迄今极少有研究关注以往研究中高创造力群体间的同质性问题。本研究以创造力问题提出能力测验调查了两所高校（一所地方高校和一所教育部直属高校）的975名大学生的创造力,通过极端组方法（extreme groups approach, EGA）为大学生创造力水平分组,考察不同创造力分组之间的差别。研究发现：地方高校和部属高校的高创造力大学生被试,在创造力的流畅性、变通性和独特性三个维度上,均存在显著差异。本研究结果提示,大学生高创造力组间可能存在质的差别,因此相关研究在外推结果时需要采取谨慎态度;研究者在实验过程中和讨论文献结果的可比性时一定要关注样本的同质性问题。     

A Principled Approach to Feature Selection in Models of Sentence Processing

Among theories of human language comprehension, cue-based memory retrieval has proven to be a useful framework for understanding when and how processing difficulty arises in the resolution of long-distance dependencies. Most previous work in this area has assumed that very general retrieval cues like [+subject] or [+singular] do the work of identifying (and sometimes misidentifying) a retrieval target in order to establish a dependency between words. However, recent work suggests that general, handpicked retrieval cues like these may not be enough to explain illusions of plausibility (Cunnings & Sturt, 2018), which can arise in sentences like The letter next to the porcelain plate shattered. Capturing such retrieval interference effects requires lexically specific features and retrieval cues, but handpicking the features is hard to do in a principled way and greatly increases modeler degrees of freedom. To remedy this, we use well-established word embedding methods for creating distributed lexical feature representations that encode information relevant for retrieval using distributed retrieval cue vectors. We show that the similarity between the feature and cue vectors (a measure of plausibility) predicts total reading times in Cunnings and Sturt’s eye-tracking data. The features can easily be plugged into existing parsing models (including cue-based retrieval and self-organized parsing), putting very different models on more equal footing and facilitating future quantitative comparisons.