A simple computational algorithm of model-based choice preference

A broadly used computational framework posits that two learning systems operate in parallel during the learning of choice preferences—namely, the model-free and model-based reinforcement-learning systems. In this study, we examined another possibility, through which model-free learning is the basic system and model-based information is its modulator. Accordingly, we proposed several modified versions of a temporal-difference learning model to explain the choice-learning process. Using the two-stage decision task developed by Daw, Gershman, Seymour, Dayan, and Dolan (2011), we compared their original computational model, which assumes a parallel learning process, and our proposed models, which assume a sequential learning process. Choice data from 23 participants showed a better fit with the proposed models. More specifically, the proposed eligibility adjustment model, which assumes that the environmental model can weight the degree of the eligibility trace, can explain choices better under both model-free and model-based controls and has a simpler computational algorithm than the original model. In addition, the forgetting learning model and its variation, which assume changes in the values of unchosen actions, substantially improved the fits to the data. Overall, we show that a hybrid computational model best fits the data. The parameters used in this model succeed in capturing individual tendencies with respect to both model use in learning and exploration behavior. This computational model provides novel insights into learning with interacting model-free and model-based components.     

Sex-Role Stereotypes in Medicine

I argue for compatibility between feminism and medicine by developing a model of the physician-other relationship which is essentially egalitarian. This entails rejection of (a) a paternalistic model which reinforces sex-role stereotypes, (b) a maternalistic model which exclusively emphasizes patient autonomy, and (c) a model which focuses on the physician's conscience. The model I propose (parentalism) captures the complexity and dynamism of the physician-other relationship, by stressing mutuality in respect for autonomy and regard for each other's interests.     

Performance Excellence: A Personal Perspective on the Link Between Sport and Business

This article provides a personal perspective on the link between excellence in sport and business. It traces the author's transition from sport psychologist to business consultant before identifying specific areas in which direct links can be drawn between the two domains. Specifically, five major areas are addressed: organizational issues, in which a demands, supports, constraints approach is outlined; stress, including a model of stress in leaders and a model of stress and coping; leadership, in which a model of leadership and how it relates to performance is presented; high-performing teams, based on a create, unite, perform (CUP) model of team building, team work, and team effectiveness; and one-to-one coaching/consulting, in which common areas across sport and business are identified. The general conclusion is that the principles of elite performance in sport are easily transferable to the business context, and also that sport has a considerable amount to learn from excellence in business.     

Expected performance at the human/computer interface as a function of user proficiency and system power

How do managers expect the proficiency of users and the power of the computers to determine overall performance? Five different models are proposed: (a) a matching model in which optimal performance is achieved when the power of the system is judged to be compatible with the proficiency of the user, (b) an averaging model in which expected performance is the average of the values of user proficiency and system power, (c) a multiplying model in which performance is the product of the values of user proficiency and system power, (d) a human/computer ratio model in which performance is determined by the ratio of system power over total effort, and (e) a computer/human ratio model in which performance is determined by the ratio of user proficiency over total effort. The applicability of these models was assessed by having managers and students of management predict performance in human/computer systems from information about the user's proficiency with computers and the power of the system. Participants rated 16 combinations of user proficiency and system power from a 4 × 4 factorial design. The pattern of ratings indicated that 51 per cent used a multiplying model and 25 percent used an averaging model; whereas, only 6 percent used the matching model and 4 percent used a ratio model. The remaining 14 percent did not follow any model clearly. Implications of these results were discussed for the design of the human/ computer interface, training and selection of users, and the cost-benefit tradeoffs for investment in user training versus equipment acquisition.     

Models for measurement,precision, and the nondichotomization of graded responses

It is common in educational, psychological, and social measurement in general, to collect data in the form of graded responses and then to combine adjacent categories. It has been argued that because the division of the continuum into categories is arbitrary, any model used for analyzing graded responses should accommodate such action. Specifically, Jansen and Roskam (1986) enunciate ajoining assumption which specifies that if two categoriesj andk are combined to form categoryh, then the probability of a response inh should equal the sum of the probabilities of responses inj andk. As a result, they question the use of the Rasch model for graded responses which explicitly prohibits the combining of categories after the data are collected except in more or less degenerate cases. However, the Rasch model is derived from requirements of invariance of comparisons of entities with respect to different instruments, which might include different partitions of the continuum, and is consistent with fundamental measurement. Therefore, there is a strong case that the mathematical implication of the Rasch model should be studied further in order to understand how and why it conflicts with the joining assumption. This paper pursues the mathematics of the Rasch model and establishes, through a special case when the sizes of the categories are equal and when the model is expressed in the multiplicative metric, that its probability distribution reflects the precision with which the data are collected, and that if a pair of categories is collapsed after the data are collected, it no longer reflects the original precision. As a consequence, and not because of a qualitative change in the variable, the joining assumption is destroyed when categories are combined. Implications of the choice between a model which satisfies the joining assumption or one which reflects on the precision of the data collection considered are discussed.     

On choosing between deterministic and indeterministic models: underdetermination and indirect evidence

There are results which show that measure-theoretic deterministic models and stochastic models are observationally equivalent. Thus there is a choice between a deterministic and an indeterministic model and the question arises: Which model is preferable relative to evidence? If the evidence equally supports both models, there is underdetermination. This paper first distinguishes between different kinds of choice and clarifies the possible resulting types of underdetermination. Then a new answer is presented: the focus is on the choice between a Newtonian deterministic model supported by indirect evidence from other Newtonian models which invoke similar additional assumptions about the physical systems and a stochastic model that is not supported by indirect evidence. It is argued that the deterministic model is preferable. The argument against underdetermination is then generalised to a broader class of cases. Finally, the paper criticises the extant philosophical answers in relation to the preferable model. Winnie’s (1998) argument for the deterministic model is shown to deliver the correct conclusion relative to observations which are possible in principle and where there are no limits, in principle, on observational accuracy (the type of choice Winnie was concerned with). However, in practice the argument fails. A further point made is that Hoefer’s (2008) argument for the deterministic model is untenable.     

现代测量理论下四大认知诊断模型述评

该文介绍并比较了现代测量理论下四大认知诊断模型的思想方法、模型结构及各自的特点性能等。LLTM是一个较早的认知诊断模型,它实现了认知与测量的结合;规则空间模型实现了对认知结构的诊断,并创造性地提出了Q矩阵理论;统一模型与融合模型是同一类模型：两者均沿用了规则空间模型的Q矩阵方法,但克服了规则空间模型中的一些不足;融合模型被认为是二十一世纪初创立的一个很成功的认知诊断模型。     

In defence of a ratio model for movement detection at threshold

Sutherland (1961) proposed that the detection of motion might depend upon the ratios of firings in cells sensitive to movement in opposite directions. Sekuler and his collaborators have argued that the notion of a ratio mechanism at threshold is wrong. The findings and arguments upon which this conclusion was based are challenged, an explicit model is described which provides an account of data previously held to be inconsistent with a ratio model, and an experiment is reported which provides unequivocal support for the ratio model and whose findings are inconsistent with the predictions from Sekuler's “independence” model.     

Usefulness and limitation of spatial representation

What discussed herein is not an “open problem” in the sense of mathematics. It is a problem that psychologists should keep in mind when presenting a formal model. A model will be useful for phenomena on which the model has been formulated. However, the model may contain a number of remaining properties that not necessarily represent related psychological phenomena adequately. The situation is analogous to that the particle model of light does not represent diffraction whereas the wave model of light is not adequate for the Compton effect. When presenting a model, mathematical psychologists should be especially keen about this point. The problem is discussed with a concrete example.     

A rasch model for partial credit scoring

A unidimensional latent trait model for responses scored in two or more ordered categories is developed. This “Partial Credit” model is a member of the family of latent trait models which share the property of parameter separability and so permit “specifically objective” comparisons of persons and items. The model can be viewed as an extension of Andrich's Rating Scale model to situations in which ordered response alternatives are free to vary in number and structure from item to item. The difference between the parameters in this model and the “category boundaries” in Samejima's Graded Response model is demonstrated. An unconditional maximum likelihood procedure for estimating the model parameters is developed. Preparation of this paper was supported by grants from the Spencer Foundation and the National Institute for Justice. I would like to thank Professor Benjamin D. Wright of the University of Chicago for his very kind help with the various drafts of this paper.     

Yes,no, maybe so: a veritistic approach to echo chambers using a trichotomous belief model

I approach the study of echo chambers from the perspective of veritistic social epistemology. A trichotomous belief model is developed featuring a mechanism by which agents will have a tendency to form agreement in the community. The model is implemented as an agent-based model in NetLogo and then used to investigate a social practice called Impartiality, which is a plausible means for resisting or dismantling echo chambers. The implementation exposes additional factors that need close consideration in an evaluation of Impartiality. In particular, resisting or dismantling echo chambers requires the selection of sufficiently low levels of doxastic entrenchment, but this comes with other tradeoffs.     

A computer model of auditory stream segregation

A computer model is described which simulates some aspects of auditory stream segregation. The model emphasizes the explanatory power of simple physiological principles operating at a peripheral rather than a central level. The model consists of a multi-channel bandpass-filter bank with a “noisy” output and an attentional mechanism that responds selectively to the channel with the greatest activity. A “leaky integration” principle allows channel excitation to accumulate and dissipate over time. The model produces similar results to two experimental demonstrations of streaming phenomena, which are presented in detail. These results are discussed in terms of the “emergent properties” of a system governed by simple physiological principles. As such the model is contrasted with higher-level Gestalt explanations of the same phenomena while accepting that they may constitute complementary kinds of explanation.     

Kim On Reduction

In Mind in a Physical World (1998), Jaegwon Kim has recently extended his ongoing critique of `non-reductive materialist' positions in philosophy of mind by arguing that Nagel's model of reduction is the wrong paradigm in terms of which to contest the issue of psychophysical reduction, and that an altogether different model of scientific reduction – a functional model of reduction – is needed. In this paper I argue, first, that Kim's conception of the Nagelian model is substantially impoverished and potentially misleading; second, that his own functional model is problematic in several respects; and, third, that the basic idea underlying his functional model can well be accommodated within a properly reinterpreted Nagelian model. I conclude with some reflections on the issue of psychophysical reduction.     

Improving precision of ability estimation: Getting more from response times

By considering information about response time (RT) in addition to response accuracy (RA), joint models for RA and RT such as the hierarchical model (van der Linden, 2007) can improve the precision with which ability is estimated over models that only consider RA. The hierarchical model, however, assumes that only the person's speed is informative of ability. This assumption of conditional independence between RT and ability given speed may be violated in practice, and ignores collateral information about ability that may be present in the residual RTs. We propose a posterior predictive check for evaluating the assumption of conditional independence between RT and ability given speed. Furthermore, we propose an extension of the hierarchical model that contains cross-loadings between ability and RT, which enables one to take additional collateral information about ability into account beyond what is possible in the standard hierarchical model. A Bayesian estimation procedure is proposed for the model. Using simulation studies, the performance of the model is evaluated in terms of parameter recovery, and the possible gain in precision over the standard hierarchical model and an RA-only model is considered. The model is applied to data from a high-stakes educational test.     

A consultation model for school psychological services

This paper proposes a consultative model for school psychology which includes several techniques that have been independently presented in the past. The primary contribution is the integration of these different methods into a model which is specifically designed for school psychologists. The proposed model is adapted from Caplan (1970), and it includes four levels of functioning: I) Direct Service to the Child; II) Indirect Service to the Child; III) Direct Service to the Teacher; and IV) Service to the School System; a distinction is made between the content and process of consultation, and a shift in emphasis from level I to the remaining levels is suggested.     

Nonlinear submodels of orthogonal linear models

A model containing linear and nonlinear parameters (e. g., a spatial multidimensional scaling model) is viewed as a linear model with free and constrained parameters. Since the rank deficiency of the design matrix for the linear model determines the number of side conditions needed to identify its parameters, the design matrix acts as a guide in identifying the parameters of the nonlinear model. Moreover, if the design matrix and the uniqueness conditions constitute anorthogonal linear model, then the associated error sum of squares may be expressed in a form which separates the free and constrained parameters. This immediately provides least squares estimates of the free parameters, while simplifying the least squares problem for those which are constrained. When the least squares estimates for a nonlinear model are obtained in this way,i.e. by conceptualizing it as a submodel, the final error sum of squares for the nonlinear model will be arestricted minimum whenever the side conditions of the model become real restrictions upon its submodel. In this case the design matrix for the embracing orthogonal model serves as a guide in introducing parameters into the nonlinear model as well as in identifying these parameters. The method of overwriting a nonlinear model with an orthogonal linear model is illustrated with two different spatial analyses of a three-way preference table.     

The magical number seven and some other features of category scaling: Properties of a model for absolute judgment

A model for absolute judgment is presented. This is derived from a theory of the processes which set and maintain response criteria (M. Treisman & T. C. Williams, 1984, Psychological Review, 91, 68–111) which has been applied to a number of problems in psychophysics. A Thurstonian model is assumed as a basis for absolute judgment, and criterion-setting theory is applied to the criteria in this model. The question is then considered, to what extent can such a model account for the main findings that have been obtained in category scaling? The range of explanations that the model can provide is investigated by means of computer simulation. It appears that features such as the upper limit on information transmission as the number of stimuli increases, the effect of stimulus range on information transmission, the accuracy edge effect, the resolution edge effect, the central tendency of judgment, stimulus and response dependencies, and related phenomena can be reproduced by simulations of the model.     

Testing the reference-dependent model: an experiment on asymmetrically dominated reference points

Standard choice theory assumes choice to be independent of the point of reference. Based on a number of studies which challenge this assumption, Tversky and Kahneman have proposed a reference-dependent model which captures the influence of reference points on individual choice. If choice is reference-dependent, switching the reference point so that it is first dominated by x and then by y increases the likelihood of choosing y. Switching the location of an asymmetrically dominated reference point without altering the dominance relationship should also influence reference-dependent choice in a predicted manner. In this paper the reference-dependent model is tested in two experiments which focus on asymmetrically dominated reference points. The results of these experiments give further confirmation to the reference-dependent model. © 1998 John Wiley & Sons, Ltd.     

A formal model for structuring local perceptions of environmental space

The problem of constructing computational models of space that mimic those found in human spatial reasoning is addressed. This paper extends a formal model that addressed point objects in a 2D world to include the presence of line objects and barriers. The problem consists of determining an appropriate global model for the spatial configuration given a sequence of local views or observations. A formal model is proposed based on constraint network theory. The model leads to the identification of stable regions within which perceptual information about the environment changes slowly, and zones of transition within which the perceptual information changes more quickly. A special case of transition zones is a gateway, which may be viewed as a kind of discontinuity or singularity in the model. It is expected that the model obtained will be used to mimic human mental representations of navigable outdoor environments.