Analysis of a two-alternative force-choice signal detection theory model

A basic problem in psychophysics is recovering the mean internal response and noise amplitude from sensory discrimination data. Since these components cannot be estimated independently, several indirect methods were suggested to resolve this issue. Here we analyze the two-alternative force-choice method (2AFC), using a signal detection theory approach, and show analytically that the 2AFC data are not always suitable for a reliable estimation of the mean internal responses and noise amplitudes. Specifically, we show that there is a subspace of internal parameters that are highly sensitive to sampling errors (singularities), which results in a large range of estimated parameters with a finite number of experimental trials. Four types of singular models were identified, including the models where the noise amplitude is independent of the stimulus intensity, a situation often encountered in visual contrast discrimination. Finally, we consider two ways to avoid singularities: (1) inserting external noise to the stimuli, and (2) using one-interval forced-choice scaling methods (such as the Thurstonian scaling method for successive intervals).     

Mapping the Structure of Human Values through Conceptual Representations

The present research provides the first direct examination of human values through concept categorization tasks that entail judging the meaning of values. Seven studies containing data from nine samples (N = 1086) in two countries (the UK and Brazil) asked participants to compare the meaning of different values found within influential quasi‐circumplex model of values. Different methods were used across experiments, including direct similarity judgment tasks, pile sorting, and spatial arrangement. The results of these diverse conceptual assessments corresponded to spatial configurations that are broadly convergent with Schwartz's model, both between and within participants. © 2018 The Authors. European Journal of Personality published by John Wiley & Sons Ltd on behalf of European Association of Personality Psychology     

Le fonctionnement optimal psychologique : apports conceptuels et méthodologiques

In this study, we are operationalizing a new construct: the optimal psychological functioning (OPF). The dimensions of the construct are considered from a historical and a conceptual background then a heuristic approach is mobilized based on three precise rules and the tripartite conception of the mind, i.e. cognitive, affective and conative. The sample is made of 1066 French workers of age 18 to 60 originating from a diverse sociocultural and geographic background. The methodology relies on latent variable modeling. The results give rise to a bifactor structural equations modeling (Bi-ESEM) model with six domain-specific factors demonstrating a very good fit and high psychometric properties. Construct validity was tested against Keyes's positive mental health via the Mental Health Continuum Short Form (MHC-SF) (Keyes, 2002, 2005) and a construct on psychosocial risks (PSR). The OPF strongly, very significantly, and positively predicts positive mental health, while it negatively predicts absenteeism, presenteeism and turnover intentions.     

Future‐biased search: the quest for the ideal

Decision‐makers with ideal candidates already in mind often extend search beyond optimal endpoints when searching for the best option among a sequential list of alternatives. Extended search is investigated here using three laboratory experiments; individuals in these tasks exhibit future‐bias, delaying choice beyond normative benchmarks. Searchers' behavior is consistent with setting high thresholds based on a focal ideal outcome without full attention to its probability or the value of second‐best alternatives; the behavior is partially debiased by manipulating which outcomes are in the searchers' focal set. Documenting future‐bias in sequential search tasks offers new insights for understanding self‐control and intertemporal choice by providing a situation in which thresholds may be set too high and myopic behavior does not prevail. Copyright © 2008 John Wiley & Sons, Ltd.     

Scaling questions: asking and answering them in counselling1

Solution-focused counsellors use “scaling questions” to construct understandings of clients’ concerns and solutions to them. We examine how these questions are asked and answered, offering evidence of what is constructed from within counselling discourse. Also, clients and counsellors offer their retrospective accounts of their participation in question and answer sequences in their dialogues. We conclude by speaking to the implications we see from this research as it relates to collaborative and resourceful dialogue between counsellors and clients.     

Risk-sensitive choice in humans as a function of an earnings budget

Risky choice in 3 adult humans was investigated across procedural manipulations designed to model energy-budget manipulations conducted with nonhumans. Subjects were presented with repeated choices between a fixed and a variable number of points. An energy budget was simulated by use of an earnings budget, defined as the number of points needed within a block of trials for points to be exchanged for money. During positive earnings-budget conditions, exclusive preference for the fixed option met the earnings requirement. During negative earnings-budget conditions, exclusive preference for the certain option did not meet the earnings requirement, but choice for the variable option met the requirement probabilistically. Choice was generally risk averse (the fixed option was preferred) when the earnings budget was positive and risk prone (the variable option was preferred) when the earnings budget was negative. Furthermore, choice was most risk prone during negative earnings-budget conditions in which the earnings requirement was most stringent. Local choice patterns were also frequently consistent with the predictions of a dynamic optimization model, indicating that choice was simultaneously sensitive to short-term choice contingencies, current point earnings, and the earnings requirement. Overall, these results show that the patterns of risky choice generated by energy-budget variables can also be produced by choice contingencies that do not involve immediate survival, and that risky choice in humans may be similar to that shown in nonhumans when choice is studied under analogous experimental conditions.     

Upper bounds for Kruskal's stress

In this paper the relationships between the two formulas for stress proposed by Kruskal in 1964 are studied. It is shown that stress formula one has a system of nontrivial upper bounds. It seems likely that minimization of this loss function will be liable to produce solutions for which this upper bound is small. These are regularly shaped configurations. Even though stress formula two yields less equivocal results, it seems to be expected that minimization of this loss function will tend to produce configurations in which the points are clumped. These results give no clue as to which of the two loss functions is to be preferred.This study has been supported by the Nederlandse Organisatie voor Zuiver-Wetenschappelijk Onderzoek (Netherlands Organization for the Advancement of Pure Research), under grant 56-146.Comments by Willem Heiser and Frank Critichley have been very helpful.The second author presently is employed by the Netherlands Central Bureau of Statistics, Voorburg.     

Confidence regions for INDSCAL using the jackknife and bootstrap techniques

Bootstrap and jackknife techniques are used to estimate ellipsoidal confidence regions of group stimulus points derived from INDSCAL. The validity of these estimates is assessed through Monte Carlo analysis. Asymptotic estimates of confidence regions based on a MULTISCALE solution are also evaluated. Our findings suggest that the bootstrap and jackknife techniques may be used to provide statements regarding the accuracy of the relative locations of points in space. Our findings also suggest that MULTISCALE asymptotic estimates of confidence regions based on small samples provide an optimistic view of the actual statistical reliability of the solution. The authors wish to thank Geert DeSoete, Richard A. Harshman, William Heiser, Jon Kettenring, Joseph B. Kruskal, Jacqueline Meulman, James O. Ramsay, John W. Tukey, Paul A. Tukey, and Mike Wish. Sharon L. Weinberg is a consultant at AT&T Bell Laboratories, Murray Hill, New Jersey 07974.     

Alternative solutions for optimization problems in generalizability theory

Solutions for the problem of maximizing the generalizability coefficient under a budget constraint are presented. It is shown that the Cauchy-Schwarz inequality can be applied to derive optimal continuous solutions for the number of conditions of each facet. The author thanks Sjoerd Baas and Agnes Broeren for their many helpful remarks.     

Sequential estimation in multidimensional scaling

The concept of sequential estimation is introduced in multidimensional scaling (MDS). The sequential estimation method developed in this paper refers to continually updating estimates of a configuration as new observations are added. This method has a number of advantages, such as a locally optimal design of the experiment can be easily constructed, and dynamic experimentation is made possible. Using artificial data, the performance of our sequential method is illustrated.We are indebted to anonymous reviewers for their suggestions. In addition, we thank Dr. Frank Critchley for his helpful comments on our Q/S algorithm.