Beyond statistical inference: A decision theory for science

Traditional null hypothesis significance testing does not yield the probability of the null or its alternative and, therefore, cannot logically ground scientific decisions. The decision theory proposed here calculates the expected utility of an effect on the basis of (1) the probability of replicating it and (2) a utility function on its size. It takes significance tests—which place all value on the replicability of an effect and none on its magnitude—as a special case, one in which the cost of a false positive is revealed to be an order of magnitude greater than the value of a true positive. More realistic utility functions credit both replicability and effect size, integrating them for a single index of merit. The analysis incorporates opportunity cost and is consistent with alternate measures of effect size, such as r2 and information transmission, and with Bayesian model selection criteria. An alternate formulation is functionally equivalent to the formal theory, transparent, and easy to compute.     

Boredom: Practical consequences and a theory

Boredom is defined as a unique psychophysiological state possessing interrelated and inseparable emotional, motivational, perceptual and cognitive concomitants. Practical consequences of boredom are reviewed, including diminished performance efficiency, general life satisfaction and health. Finally, the outline of a theoretical model is presented.     

Correlation and prediction in ordinal test theory

Based on the test theory model for ordinal measurements proposed by Schulman and Haden, the present paper considers correlations between tests, attenuation, regressions involving true and observed scores, and prediction of test reliability.The population correlation between tests is shown to be related to the expected sample correlation for samples of sizen ₁ andn ₂. Errors of estimation, measurement and prediction are found to be similar to their counterparts in interval test theory, while attenuation is identical to its counterpart. The bias in estimating population reliability from sample data is compared for Kendall's tau and Spearman's rho.The author wishes to thank the referees for their helpful comments on an earlier draft of this paper, and in particular, for the suggested alternative methods of establishing some of the presented results.     

Age differences in motivational orientation toward physical activity: an application of social-cognitive theory

According to social-cognitive theory, an individual's motivation to engage in physical activity is based on three postulates: self-efficacy, outcome expectations, and self-evaluated satisfaction or dissatisfaction. The purpose of the present study was to examine age, gender, level of education, and level of activity in relation to those postulates in 2,298 Australians aged between 18 and 78. The authors conducted regression analyses for self-efficacy and for outcome expectations as dependent variables; age, gender, education level, and level of physical activity served as independent variables. Chi-square analyses assessed differences in the health incentive to exercise, the perceived level of activity, and the perceived level of fitness. Results indicated significant age differences on all variables. The older individual felt lower self-efficacy in relation to physical activity and expected fewer benefits from participating in physical activity. However, older individuals who engaged in physical activity rated themselves as more active and fit than nonexercisers of their same age and gender. Physical activity and level of education were positively correlated with self-efficacy, and men were more efficacious than women were. The implications are that interventions aimed at increasing participation in physical activity should take into consideration differences in incentives.     

Decisional separability, model identification, and statistical inference in the general recognition theory framework

Recent work in the general recognition theory (GRT) framework indicates that there are serious problems with some of the inferential machinery designed to detect perceptual and decisional interactions in multidimensional identification and categorization (Mack, Richler, Gauthier, & Palmeri, 2011). These problems are more extensive than previously recognized, as we show through new analytic and simulation-based results indicating that failure of decisional separability is not identifiable in the Gaussian GRT model with either of two common response selection models. We also describe previously unnoticed formal implicational relationships between seemingly distinct tests of perceptual and decisional interactions. Augmenting these formal results with further simulations, we show that tests based on marginal signal detection parameters produce unacceptably high rates of incorrect statistical significance. We conclude by discussing the scope of the implications of these results, and we offer a brief sketch of a new set of recommendations for testing relationships between dimensions in perception and response selection in the full-factorial identification paradigm.     

Truth or consequences: the role of philosophers in policy-making

Reflecting on his experiences as a staff philosopher on the President's Commission for the Study of Ethical Problems in Medicine and Biomedical and Behavioral Research and with other advisory bodies, Brock contends that there is a deep conflict between the goals and constraints of the public policy process and those of scholarly activity in general and philosophical activity in particular. Whereas unconstrained search for the truth is the central virtue of scholarly work, the first concern of policy makers is the impact of their actions on policies and people. The need to persuade policy makers and to maintain their own credibility leads philosophers to cut and trim their views. While the philosophers should be open to radical change if persuasive argument supports it, policy makers deal in incremental change. Philosophers can help widen the policy agenda, but their contribution should be limited and temporary and their primary base should remain an academic one.     

Asymmetry and performance: toward a neurodevelopmental theory

Hemispheric asymmetry implies the existence of developmental influences that affect one hemisphere more than the other. However, those influences are poorly understood. One simple view is that asymmetry may exist because of a relationship between a mental process' degree of lateralization and how well it functions. Data scaling issues have largely prevented such investigations, but it is shown that scaling effects are minimized after correction for ceiling and floor effects. After correction, lateralization-performance correlations are pervasive. However, while some correlations are positive, others are negative, with the direction depending on the underlying lateralized process. Two hypotheses are proposed that can account for these relationships by pointing either to individual differences in maturation of the corpus callosum or to developmental limits encountered at different ages of childhood. Their investigation should contribute toward a neurodevelopmental theory of hemispheric asymmetry.     

Conditionals: a theory of meaning,pragmatics, and inference

The authors outline a theory of conditionals of the form If A then C and If A then possibly C. The 2 sorts of conditional have separate core meanings that refer to sets of possibilities. Knowledge, pragmatics, and semantics can modulate these meanings. Modulation can add information about temporal and other relations between antecedent and consequent. It can also prevent the construction of possibilities to yield 10 distinct sets of possibilities to which conditionals can refer. The mental representation of a conditional normally makes explicit only the possibilities in which its antecedent is true, yielding other possibilities implicitly. Reasoners tend to focus on the explicit possibilities. The theory predicts the major phenomena of understanding and reasoning with conditionals.     

Imagination inflation: a statistical artifact of regression toward the mean

In the imagination inflation procedure of Garry, Manning, Loftus, and Sherman (1996), subjects rated a list of events in terms of how likely each was to have occurred in their childhood. Two weeks later, some of the events were imagined; control events were not. The subjects then rated the likelihood of occurrence for each event a second time. Garry et al. (1996) reported that the act of imagining the target events led to increased ratings of likelihood. This finding has been interpreted as indicating that false events can be suggestively planted in memory by simply having people imagine them. The present study tests and confirms the hypothesis that the results that have been attributed to imagination inflation are simply a statistical artifact of regression toward the mean. The experiment of Garry et al. (1996) was reproduced (with some procedural changes), using younger and older adults. The results of Garry et al. (1996) were replicated; likelihood ratings for events initially rated low in likelihood did increase from Time 1 to Time 2. However, ratings for events initially rated high in likelihood decreased under the same conditions, and these results were consistent with the imagined target events, the target events not imagined, and the nontarget events.     

On objectivity and subjectivity in statistical inference: A response to Mayo

In this paper we respond to the article An Objective Theory of Statistical Testing by D. G. Mayo (1983). We argue that the theory of testing developed by Mayo, NPT*, is neither novel nor objective. We also respond to the claims made by Mayo against Bayesian theory.     

Making good choices: toward a theory of well-being in medicine

The principle of beneficence directs healthcare practitioners to promote patients’ well-being, ensuring that the patients’ best interests guide treatment decisions. Because there are a number of distinct theories of well-being that could lead to different conclusions about the patient’s good, a careful consideration of which account is best suited for use in the medical context is needed. While there has been some discussion of the differences between subjective and objective theories of well-being within the bioethics literature, less attention has been given to the questions of what work a theory of well-being needs to do in bioethics and which standards of success ought to be used in selecting a theory of well-being for use in medicine. In this article, I argue that traditional theories of well-being developed in philosophy are not well suited to meet the needs of the medical context. For the principle of beneficence to be most useful, the underlying account of well-being should satisfy two conditions: first, it needs to lead to a concrete, action-guiding determination of the patient’s good; and, second, any recommendations it offers need to be justifiable to patients. Standard accounts of well-being have difficulty satisfying both conditions. Exploring the limitations of these theories when applied to treatment dilemmas helps point the way toward the development of an account of well-being better suited to healthcare.     

Beyond quantity: Individual differences in working memory and the ordinal understanding of numerical symbols

In two different contexts, we examined the hypothesis that individual differences in working memory (WM) capacity are related to the tendency to infer complex, ordinal relationships between numerical symbols. In Experiment 1, we assessed whether this tendency arises in a learning context that involves mapping novel symbols to quantities by training adult participants to associate dot-quantities with novel symbols, the overall relative order of which had to be inferred. Performance was best for participants who were higher in WM capacity (HWMs). HWMs also learned ordinal information about the symbols that lower WM individuals (LWMs) did not. In Experiment 2, we examined whether WM relates to performance when participants are explicitly instructed to make numerical order judgments about highly enculturated numerical symbols by having participants indicate whether sets of three Arabic numerals were in increasing order. All participants responded faster when sequential sets (3-4-5) were in order than when they were not. However, only HWMs responded faster when non-sequential, patterned sets (1-3-5) were in order, suggesting they were accessing ordinal associations that LWMs were not. Taken together, these experiments indicate that WM capacity plays a key role in extending symbolic number representations beyond their quantity referents to include symbol-symbol ordinal associations, both in a learning context and in terms of explicitly accessing ordinal relationships in highly enculturated stimuli.     

Grouping and emergent features in vision: toward a theory of basic Gestalts

Gestalt phenomena are often so powerful that mere demonstrations can confirm their existence, but Gestalts have proven hard to define and measure. Here we outline a theory of basic Gestalts (TBG) that defines Gestalts as emergent features (EFs). The logic relies on discovering wholes that are more discriminable than are the parts from which they are built. These wholes contain EFs that can act as basic features in human vision. As context is added to a visual stimulus, a hierarchy of EFs appears. Starting with a single dot and adding a second yields the first two potential EFs: the proximity (distance) and orientation (angle) between the two dots. A third dot introduces two more potential EFs: symmetry and linearity; a fourth dot produces surroundedness. This hierarchy may extend to collinearity, parallelism, closure, and more. We use the magnitude of Configural Superiority Effects to measure the salience of EFs on a common scale, potentially letting us compare the strengths of various grouping principles. TBG appears promising, with our initial experiments establishing and quantifying at least three basic EFs in human vision.