A comparison of natural-image-based models of simple-cell coding

Models such as that of Olshausen and Field (O&F, 1997 Vision Research 37 3311-3325) and principal components analysis (PCA) have been used to model simple-cell receptive fields, and to try to elucidate the statistical principles underlying visual coding in area V1. They connect the statistical structure of natural images with the statistical structure of the coding used in V1. The O&F model has created particular interest because the basis functions it produces resemble the receptive fields of simple cells. We evaluate these models in terms of their sparseness and dispersal, both of which have been suggested as desirable for efficient visual coding. However, both attributes have been defined ambiguously in the literature, and we have been obliged to formulate specific definitions in order to allow any comparison between models at all. We find that both attributes are strongly affected by any preprocessing (e.g. spectral pseudo-whitening or a logarithmic transformation) which is often applied to images before they are analysed by PCA or the O&F model. We also find that measures of sparseness are affected by the size of the filters--PCA filters with small receptive fields appear sparser than PCA filters with larger spatial extent. Finally, normalisation of the means and variances of filters influences measures of dispersal. It is necessary to control for all of these factors before making any comparisons between different models. Having taken these factors into account, we find that the code produced by the O&F model is somewhat sparser than the code produced by PCA. However, the difference is rather smaller than might have been expected, and a measure of dispersal is required to distinguish clearly between the two models.     

A comparison of three simple test theory models

In very simple test theory models such as the Rasch model, a single parameter is used to represent the ability of any examinee or the difficulty of any item. Simple models such as these provide very important points of departure for more detailed modeling when a substantial amount of data are available, and are themselves of real practical value for small or even medium samples. They can also serve a normative role in test design.As an alternative to the Rasch model, or the Rasch model with a correction for guessing, a simple model is introduced which characterizes strength of response in terms of the ratio of ability and difficulty parameters rather than their difference. This model provides a natural account of guessing, and has other useful things to contribute as well. It also offers an alternative to the Rasch model with the usual correction for guessing. The three models are compared in terms of statistical properties and fits to actual data. The goal of the paper is to widen the range of minimal models available to test analysts.This research was supported by grant AP320 from the Natural Sciences and Engineering Research Council of Canada. The author is grateful for discussions with M. Abrahamowicz, I. Molenaar, D. Thissen, and H. Wainer.     

A comparison of alternative theoretical approaches to smoking cessation and relapse

Two theoretical approaches to smoking cessation were compared. Participants were randomly assigned either to (a) a traditional treatment program that used contingency contracting and that emphasized the necessity for absolute abstinence (AA) or to (b) a relapse-prevention (RP) treatment that focused on gradual acquisition of nonsmoking skills. It was hypothesized that participants in the RP treatment would be less successful initially but would have better maintenance skills and thus would relapse less during a 1-year follow-up period. Each program was evaluated in two formats: group-based treatment and self-help materials. Results indicated comparable 1-year abstinence rates for all treatments, although more participants dropped out of the self-help formats. Participants in the RP intervention were more likely to lapse sooner after quitting and were more likely to quit again during the 1-year maintenance period. Exploratory analyses of successful participants suggested that women were more successful in the RP program and that men had greater success with the AA approach.     

A structural comparison between state and trait self-regulation models

State and trait-regulation models were compared in 315 eleventh-graders using simultaneous confirmatory factor analysis. Each of the first-, second-, and third-order factor models was found to describe the data from both state and trait measures well. In both state and trait self-regulation models, the third-order factor, self-regulation, is composed of metacognition and effort, and the second-order factor, metacognition, is composed of awareness, cognitive strategy, planning, and self-checking. Findings of invariant factor loadings and factor correlations across state and trait measures indicate that the state and trait self-regulatory factor structures are similar. Unlike the state-trait distinctions found in affective personality domain, clear state-trait distinction was not found in this cognitive domain. In both measures, students who engaged more frequently in metacognitive activities and effort use in their mathematical problem solving performed better than those who did not.     

A comparison of sequential sampling models for two-choice reaction time

The authors evaluated 4 sequential sampling models for 2-choice decisions--the Wiener diffusion, Ornstein-Uhlenbeck (OU) diffusion, accumulator, and Poisson counter models--by fitting them to the response time (RT) distributions and accuracy data from 3 experiments. Each of the models was augmented with assumptions of variability across trials in the rate of accumulation of evidence from stimuli, the values of response criteria, and the value of base RT across trials. Although there was substantial model mimicry, empirical conditions were identified under which the models make discriminably different predictions. The best accounts of the data were provided by the Wiener diffusion model, the OU model with small-to-moderate decay, and the accumulator model with long-tailed (exponential) distributions of criteria, although the last was unable to produce error RTs shorter than correct RTs. The relationship between these models and 3 recent, neurally inspired models was also examined.     

Surface dyslexia: A case report and some theoretical implications to reading models

This paper reports on the psycholinguistic investigation of a surface dyslexic aphasic patient's abilities to handle written material. The analysis of paralexic errors produced in reading aloud single words and nonwords classically suggested that the patient was using an analytical strategy parsing the letter string stimulus, from left to right, into graphemes, and assigning phonemic values to graphemes. The patient's results were found to be sensitive to irregularities in correspondence between graphemes and phonemes not only in reading aloud but in lexical decisions, writing on dictation, rhyming, and written-word comprehension. Moreover, the patient's linguistic behavior brought out the reverse pattern observed in deep-dyslexic performances within word/nonword and content/function word dimensions. It was found that some semantic information about written words could be retrieved from both phonological and nonphonological processes presumably operating concurrently and both providing converging or conflicting pieces of meaning to the understanding of written words. Some considerations derived from the observation of this pathological reading behavior are discussed, contributing to a psycholinguistic model of normal reading.     

A list of English homophones

A list of 382 sets of English heterographic homophones compiled from Collins Dictionary of the English Language (1979).¹     

A theoretical and empirical comparison of the all-or-none multilevel theory and the mixed model

Two theories for stimulus generalization in paired-associate learning (P.A.L.) are compared—the mixed model and the all-or-none multilevel theory. Both theories postulate basic all-or-none learning processes but differ in their mechanism for generalization. The mixed model postulates that generalization occurs only during responding; whereas, the multilevel theory postulates that generalization takes place during learning itself.     

Predicting consistent psychological test item responses: A comparison of models

The efficacy of four models for predicting the stability of a given individual's test item responses on a structured inventory was examined. Two models were based on item characteristics alone and predicted that an individual would be most likely to change responses to items with moderate endorsement probabilities, or with moderate social desirability scale values. Two other prediction models incorporated individual differences in the perception of item characteristics by predicting that unstable items would have relatively long response latencies for an individual, or would be near an individual's threshold for responding desirably to items. Results from two studies yielded support for the following conclusions: (a) a person's test item responses are relatively stable over short time intervals; (b) items to which a person will show response changes on retest can be identified to a statistically significant degree; (c) the models based on response latencies constituted in both studies a significantly better predictor than the other models examined. The implications of these results for the threshold model were discussed as were the practical and theoretical applications of the response latency-item stability relationship at the level of an individual's test protocol.     

A critical comparison of two random-walk models for two-choice reaction time

Two random-walk models for two-choice reaction time, being the sequential probability ratio test model initially suggested by Stone and the relative judgment theory recently proposed by Link, are here compared. The comparison shows the precise mathematical relation between the models, the predictions they have in common, and two points at which they differ. Three experiments concerned with the effect of stimulus probability on two-choice reaction time are examined with respect to three predictions from the models. In this three-way comparison the two models are more like each other than either is to the data; a greater variety of phenomena is revealed than either model can at present accommodate.     

A comparison of two response time models applied to perceptual matching

Two models, a Poisson race model and a diffusion model, are fit to data from a perceptual matching task. In each model, information about the similarity or the difference between two stimuli accumulates toward thresholds for either response. Stimulus variables are assumed to influence the rate at which information accumulates, and response variables are assumed to influence the level of the response thresholds. Three experiments were conducted to assess the performance of each model. In Experiment 1, observers performed under different response deadlines; in Experiment 2, response bias was manipulated by changing the relative frequency ofsame anddifferent stimuli. In Experiment 3, stimulus pairs were presented at three eccentricities: foveal, parafoveal, and peripheral. We examined whether the race and diffusion models could fit the response time and accuracy data through changes only in response parameters (for Experiments 1 and 2) or stimulus parameters (for Experiment 3). Comparisons between the two models suggest that the race model, which has not been studied extensively, can account for perceptual matching data at least as well as the diffusion model. Furthermore, without the constraints on the parameters provided by the experimental conditions, the diffusion and the race models are indistinguishable. This finding emphasizes the importance of fitting models across several conditions and imposing logical psychological constraints on the parameters of models.     

学习论视角下的教育工效学理论模型的发展与应用

教育工效学是工效学研究中长期被忽视的重要研究领域,其发展以各教育工效学模型的提出为主线。本文从模型设计、模型应用和学习论视角出发,分析了Kao模型,Smith模型和六角轴模型的理论基础,发现现有的这三个模型在设计上多从工效学角度出发,与学习论的结合不够紧密。为了给信息化教学系统设计提供更有价值的理论模型和更可行的设计方法,有必要从工效学原理与教学理论的深度衔接入手,并基于学习论的视角给模型应用和完善提供一些可行的建议。     

Consumer response to theoretical role models in school psychology

This 1972 investigation analyzed differential perceptions and preferences of teachers, principals, and school psychologists to three models of interview style: clinical, phenomenological, and social learning. A simulated psychologist-teacher interview was videotaped for each model. A sample of principals, teachers, and school psychologists evaluated each type of interview with a Q sort of statements designed to represent theory-related practices revealed in psychologist behavior. Analysis of variance of Q sort items revealed significant (p. < .001) differences in preferences. Psychologists most preferred social learning and rejected the clinical role. Teachers preferred the phenomenological approach. Principals did not indicate a preferred model. Validity of the Q sort as a measure of theoretical orientation was also demonstrated (p. < .001). The conclusion that school psychology is on a behavioristic path not yet endorsed by educators was strongly supported.     

Experimental and theoretical results for some models of random-dot-pattern discrimination

Summary The popular, but low-power, two-stimulus signal-detection paradigms are extended to generate response-criterion-dependent psychometric functions. Maximumlikelihood estimation within a sufficiently powerful experimental design is described, and theoretical conditions for the resulting psychometric functions to be monotonically increasing are presented. These results are applied to an experiment on the detection of spatial-density differences in briefly presented random-dot patterns. The results confirm, extend, and complement current notions put forth by H. B. Barlow and his co-workers on mechanisms of internal spatial-density representation and the efficiency of intermediate levels of visual processing.