Longitudinal Predictive Validity of a Learning Potential Test

The aim of this article is to provide empirical psychometric evidence of the (longitudinal) predictive validity of a learning potential measure—the Learning Potential Computerised Adaptive Test (LPCAT)—in comparison with standard static tests with school aggregate results as the criterion measure. Participants were 79 boys (mean age 12.44, SD = 0.44) and 72 girls (mean age 11.18, SD = 0.42) attending two private schools. Correlation and regression analyses were used to evaluate the predictive validity of the learning potential and standard test scores for school aggregate academic results as criterion measure. Results indicate that learning potential scores were statistically significant predictors of aggregate academic results and provided results that were comparable to those of the standard test results—providing empirical support for the use of learning potential tests in mainstream educational settings.     

A Modern Assessment Psychometric Approach to Dynamic Assessment

Although dynamic assessment (DA) has been hailed as a positive move towards fair assessment, it has generally not been used in educational or industry settings to the same extent that standard (static) tests have been. The present article attempts to elucidate how the use of Item Response Theory (IRT) and Computerised Adaptive Testing (CAT) can address some of the problems typically associated with dynamic assessment. An example of a DA tool that makes use of IRT and CAT, shows acceptable psychometric properties and is comparable to standard tests in terms of ease of administration illustrates the possibility of wider application of DA in both educational and industry settings.     

Stochastic choice models: A comparison between Bush-Mosteller and a source-independent reward-following model

Horner and Staddon (1987) argued that a class of reward-following processes defined by a property they termed ratio invariance is a better model for the probabilistic choice performance of pigeons than competing molecular accounts such as momentary maximizing, melioration, and the Bush-Mosteller model. The critical data were provided by choice distributions-distributions of a variable S, the proportion of Right choices, defined on a moving window typically 32 choices long-obtained under a frequency-dependent schedule. The schedule prescribed equal payoff probabilities, p(S), for both choices. p(S) was a maximum when S = 0.5 and declined linearly for S values above and below 0.5. Pigeons showed generally bimodal choice distributions with the modes at equal p(S) values. These data do not follow easily from melioration or momentary maximizing and are inconsistent with molar maximizing, but they may be consistent with Bush-Mosteller. We present here the results of computer simulations showing that the ratio-invariance model studied yields, as expected, choice modes at equal p(S) values, but that Bush-Mosteller, although capable of generating bimodal choice distributions, does not have choice modes at equal p(S) values.     

The effects of varying the distribution of generalization stimuli within a constant range upon the bisection of a sound-intensity interval by rats

Two male, albino rats were trained on a two-valued, self-paced, discrete-trials auditory discrimination. In the presence of a high-intensity stimulus (90 decibels SPL, 4 kiloHertz), response A was reinforced; in the presence of a low-intensity stimulus (50 decibels SPL, 4 kiloHertz), response B was reinforced. When discrimination performance was asymptotic, stimuli intermediate in intensity were presented with the training stimuli in a maintained generalization paradigm. Generalization gradients were derived from the relative frequencies of response A in the presence of each stimulus. A relative frequency of 0.50 was then determined and used as the bisection point of the intensity interval defined by the 90- and 50-decibel stimuli. The bisection point varied with the distribution of the stimuli presented in generalization. This effect was similar to context effects seen in human psychophysics.     

Conjunctive schedules of response-dependent and response-independent reinforcement

Pigeons received food when they emitted the number of responses specified by a fixed-ratio schedule, and the time specified by a fixed-time schedule had elapsed. The order of meeting the response and time requirements was irrelevant. In different conditions, stimuli signalled completion of one, both, or neither requirement. Ratio size interacted with stimulus condition to determine performance. When a stimulus signalled the end of the fixed-time period, under all ratios the birds tended to respond after the stimulus appeared. When stimuli followed both components, small ratios produced responding during the fixed-time period, and other ratios resulted in responses after the time period had elapsed. With either no stimulus changes, or with a stimulus correlated with completion of the ratio alone, responding first increased and then decreased as the ratio increased. Low and high ratios produced stable response frequencies and patterns in successive intervals. Intermediate ratios resulted in two types of performance. Intervals with long initial pauses and few responses during the fixed-time period were followed by intervals with short pauses and numerous responses and vice versa. The source of these dynamic effects was hypothesized to be number of responses per reinforcer in one condition and response-reinforcer contiguity in the other.     

The dynamic programming matching analysis of handwriting movement in delayed vision

Abstract: Dynamic programming matching analysis of the velocity profile of handwriting was used to examine temporally invariant characteristics of handwriting. This was done by comparing the performance of 12 subjects in writing five words under various delayed visual feedback conditions. The rate of temporally invariant handwriting decreased when delay of visual feedback was introduced. That is, the mean number of fluctuations or hesitations increased as a function of the delay time. This indicates that subjects wrote words by segmenting their movements into submovements. The relative positions of the boundaries of submovements was shown using dynamic programming matching analysis by the distribution of fluctuations along a time axis of templates. The results suggest the development of a segmented "move-and-wait" strategy under conditions of delayed vision. It was shown that in the "move" phase, subjects performed appropriate submovements as smoothly as in the no delay condition and waited during the delay until visual feedback caught up. The increased errors were due to inadequate segmentation of movements.     

Decision making in a dynamic situation: The effect of false alarms and time pressure

An experiment was conducted to investigate the effect of a priori probability of false alarms and time pressure on decision-making behaviour in a dynamic task environment. In order to assess whether strategy selection in a dynamic task environment would be adaptive, we modelled the task mathematically, and compared actual decision strategies to the optimal ones. In addition to the selected strategy, we also studied decision-making behaviour at a lower operational level, reflecting the amount of effort subjects are willing to spend on the decision process. Subjects were required to monitor the fitness level of a simulated athlete, who was running a race, and had to provide treatments whenever the athlete's fitness level suggested a real physiological problem. When a decline of the athlete's fitness was caused by a false alarm, a spontaneous recovery would occur after some time, without any need for intervention. Time pressure was manipulated by the rate at which the athlete's fitness level declined. Overall, subjects did not select the most efficient strategy: they dominantly selected information before applying an action, even though it would have been more profitable, and less effortful, just to apply actions. At the operational level, subjects appeared to invest less effort when the probability of false alarms increased and to invest more effort when time pressure increased. However, in contrast to the outcomes of our mathematical model, subjects adjusted the amount of intervention to the a priori probability of false alarms and not to time pressure. Together, the results indicate that the selection of a decision strategy in a dynamic task is less adaptive then is generally concluded from studies with static tasks.     

A Propositional Dynamic Logic with Qualitative Probabilities

This paper presents an -completeness theorem for a new propositional probabilistic logic, namely, the dynamic propositional logic of qualitative probabilities (D Q P), which has been introduced by the author as a dynamic extension of the logic of qualitative probabilities (Q P) introduced by Segerberg.     

Comment on fitting MA time series by structural equation models

In a recent paper by van Buuren (1997) it is concluded that parameter estimates in pure moving-average (MA) models, obtained by software for fitting structural equation models (SEMs), are biased and inefficient. In this comment it is shown that this negative finding may be due to a particular feature of van Buuren's simulation experiment. A modified procedure for fitting MA models by means of SEM software is proposed, and some of its implications are discussed.     

复杂问题解决：探索人们如何控制复杂动态系统

复杂问题解决研究的目的是探索人们如何处理复杂、动态任务。Dorner作为该领域的先驱,将计算机模拟情境作为研究工具,后来的研究者从不同的角度进行复杂问题解决研究。本文介绍了复杂问题解决研究的发展历史,总结了复杂问题解决情境的特征,包括动态性、复杂性、模糊性以及时间滞后性,进一步比较了复杂问题解决与自然决策和动态决策的差别。在此基础上,从控制系统的个体要求以及系统特征等方面总结了在Dorner的个体差异比较范式下复杂问题解决研究的进展。最后提出复杂问题解决研究的展望。