Resolving Peer Disagreements Through Imprecise Probabilities

Two compelling principles, the Reasonable Range Principle and the Preservation of Irrelevant Evidence Principle, are necessary conditions that any response to peer disagreements ought to abide by. The Reasonable Range Principle maintains that a resolution to a peer disagreement should not fall outside the range of views expressed by the peers in their dispute, whereas the Preservation of Irrelevant Evidence (PIE) Principle maintains that a resolution strategy should be able to preserve unanimous judgments of evidential irrelevance among the peers. No standard Bayesian resolution strategy satisfies the PIE Principle, however, and we give a loss aversion argument in support of PIE and against Bayes. The theory of imprecise probability allows one to satisfy both principles, and we introduce the notion of a set‐based credal judgment to frame and address a range of subtle issues that arise in peer disagreements.     

Conditionalization, A New Argument For

Probabilism in epistemology does not have to be of the Bayesian variety. The probabilist represents a person's opinion as a probability function; the Bayesian adds that rational change of opinion must take the form of conditionalizing on new evidence. I will argue that this is the correct procedure under certain special conditions. Those special conditions are important, and instantiated for example in scientific experimentation, but hardly universal. My argument will be related to the much maligned Reflection Principle (van Fraassen, 1984, 1995), and partly inspired by the work of Brian Skyrms (1987).     

Effects of response independent delivery of preferred items and the high‐probability instructional sequence on compliance

The use of the high‐probability (high‐p) instructional sequence to increase compliance, which includes issuing a series of instructions with which a participant is likely to comply immediately before issuing a low‐probability instruction, has received mixed support in the literature. Previous research has suggested that the delivery of response independent reinforcement may be as effective to increase compliance, at least for some types of instructions. In this study, we examined the effects of response independent reinforcement and the high‐p sequence on compliance with two types of instructions with two young children. Results show that neither procedure was effective for increasing compliance for either type of instruction; however, contingent access to a high preference item increased compliance. Results are discussed in terms of the conditions under which response independent delivery of high‐preference items and the high‐p instructional sequence might be effective to increase compliance.     

Reinforcers,values, and vocational maturity in adults

The purpose of the present study was to test the notion that job reinforcers and occupational values are related to vocational maturity. The importance of 21 reinforcers and 11 values were rated by 207 vocational rehabilitation clients nad 59 graduate students. The dependent measure was the Adult Vocational Maturity Index. Older subjects with more education were more vocationally mature. Those subjects who considered-(a) getting a feeling of accomplishment, (b) doing work without feeling it is morally wrong, (c) having steady employment, (d) independence, (e) opportunity to use special talents, (f) challenge, and (g) self-satisfaction-important, were high in vocational maturity. Subjects who considered such things as-(a) telling other workers what to do, (b) having the position of “somebody” in the community, and (c) prestige-important, were lower in vocational maturity. The data indicated that choice of occupational reinforcers and preferences for specified values are reflected in the individual's “vocational maturity”.     

On the nonrelation between spatial frequency and cerebral hemispheric competence

The hypothesis that the two cerebral hemispheres are specialized for processing different visual spatial frequencies is discussed in reference to Christman's (1989) review. It is suggested that the relevant results from every study reviewed by Christman which support the hypothesis can also be explained in terms of the total amount of visible information or energy contained in a visual stimulus, and the right hemisphere's relative resistance to information degradation. A recent study provides evidence in support of this total visible information/energy hypothesis, and appropriate measures of information/energy are discussed. Furthermore, results from the studies reviewed may reflect response bias and not hemispheric specialization or competence. The few studies which examine response bias support such an interpretation.     

Conditioned inhibition is not the symmetrical opposite of conditioned excitation: A test of the Rescorla-Wagner model

Rescorla and Wagner's (1972) linear associative model of learning predicts that a neutral stimulus will become weakly excitatory if it is paired with a conditioned inhibitor and the compound is not reinforced. If the inhibitor is not allowed to extinguish during these pairings, the model predicts that the neutral stimulus will become strongly excitatory. Rescorla (1971) has presented some evidence to support the former prediction of a weak effect. Experiment I tested the latter prediction of a strong effect using rats in a conditioned emotional response paradigm, and found no evidence that the pairings made the neutral stimulus excitatory. Experiment II replicated Rescorla's results, but showed that even on a relearning test the experimental group learned no faster than a novel stimulus control group.     

Undermatching and overmatching as deviations from the matching law

A model of performance under concurrent variable-interval reinforcement schedules that takes as its starting point the hypothetical “burst” structure of operant responding is presented. Undermatching and overmatching are derived from two separate, and opposing, tendencies. The first is a tendency to allocate a certain proportion of response bursts randomly to a response alternative without regard for the rate of reinforcement it provides, others being allocated according to the simple matching law. This produces undermatching. The second is a tendency to prolong response bursts that have a high probability of initiation relative to those for which initiation probability is lower. This process produces overmatching. A model embodying both tendencies predicts (1) that undermatching will be more common than overmatching, (2) that overmatching, when it occurs, will tend to be of limited extent. Both predictions are consistent with available data. The model thus accounts for undermatching and overmatching deviations from the matching law in terms of additional processes added on to behavior allocation obeying the simple matching relation. Such a model thus enables processes that have been hypothesized to underlie matching, such as some type of reinforcement rate or probability optimization, to remain as explanatory mechanisms even though the simple matching law may not generally be obeyed.     

Hierarchical structure in perceptual representation

A theoretical framework for perceptual representation is presented which proposes that information is coded in hierarchical networks of nonverbal propositions. The hierarchical structure of the representations implies selective organization: Some subsets of a figure will be encoded as integral, structural units of that figure, while others will not. A context-sensitive metric for the “goodness” of a part within a figure is developed, corresponding to the probability that the subset will be encoded as a structural unit. Converging evidence supporting this position is presented from four different tasks using simple, straight-line figures. The tasks studied are (a) dividing figures into “natural” parts, (b) rating the “goodness” of parts within figures, (c) timed verification of parts within figures, and (d) timed mental synthesis of spatially separated parts into unitary figures. The results are discussed in terms of the proposed theory of representation, the processes that operate on those representations, and the general implications of the data for perceptual theories.     

Stimulus control of responding by response-reinforcer temporal contiguity

The stimulus properties of brief disruptions in response-reinforcer temporal contiguity were investigated using a discrete trial conditional discrimination procedure. Key pecking (nondelay) or key pecking followed by a brief interval of nonpecking (delay) in the sample component produced a stimulus change (choice component). Pecks in the choice component to one of two alternatives resulted in food or blackout, conditional upon which response requirement was met in producing the choice component. A baseline condition, in which key pecking always produced the choice component and correct choices were arranged randomly, alternated with experimental conditions that included nondelay and delay values of either 0.2, 0.5, or 1.0 sec between the last key peck and the initiation of the choice component. All subjects accurately discriminated brief temporal delays between a response and stimulus change, with choice accuracy increasing for three of four subjects as the temporal disruption in contiguity increase. Implications of the research for the study of delayed reinforcement, response-independent reinforcement, and the discrimination of causality are discussed.     

Improving visual acuity in a myopic child: Assessing compliance and effectiveness

Improvements in visual acuity following vision training were evaluated for an 11$\text{1}\text{2}$-yr-old myopic male. Initial increases in the distance at which the S could discriminate letters were found. However, performance began to deteriorate as training progressed. A negative-reinforcement procedure was employed in order to rule out motivational factors potentially related to this decreased performance. Using a changing criterion within an ABCBC reversal design, the distance at which the S correctly discriminated letters increased by more than $\text{4}\text{1}\text{2}$ times and was clearly related to the reinforcement procedure.     

Risky decision: Attention and path dependency as a function of response mode

It was previously shown and was here replicated that the amount of money required to induce a subject to exchange one gamble for a second and then the second for a third depends on the second (intermediate) gamble. This path dependency cannot be explained by any of the algebraic models (including SEU), nor can it be explained as a simple attention effect. A model was put forward which explains the effect in terms of differential masking depending on a kind of stimulus—response compatibility. The effect of response mode on path dependency was examined in this study; similarity judgements showed no consistent path dependency nor did difference in rated attractiveness of gambles presented in pairs, but rated attractiveness was different for gambles presented singly. Since it might be that monetary response emphasises the monetary aspects, that is, the winning amount of the gamble, it was thought that a probability response would emphasise the probability of winning. However, when subjects were asked to set the probability of winning $ 12 which would induce them to exchange one gamble for another, not only was no path dependency observed, but the subjects' responses seemed to depend only on the difference in expected value of the gambles. This suggests the possibility of developing response-display modes which would eliminate or at least attenuate the inconsistencies observed in risky decision processes.     

Against Moral Character Evaluations: The Undetectability of Virtue and Vice

I defend the epistemic thesis that evaluations of people in terms of their moral character as good, bad, or intermediate are almost always epistemically unjustified. (1) Because most people are fragmented (they would behave deplorably in many and admirably in many other situations), one’s prior probability that any given person is fragmented should be high. (2) Because one’s information about specific people does not reliably distinguish those who are fragmented from those who are not, one’s posterior probability that any given person is fragmented should be close to one’s prior—and thus should also be high. (3) Because being fragmented entails being indeterminate (neither good nor bad nor intermediate), one’s posterior probability that any given person is indeterminate should also be high—and the epistemic thesis follows. (1) and (3) rely on previous work; here I support (2) by using a mathematical result together with empirical evidence from personality psychology.     

Protection motivation and self-efficacy: A revised theory of fear appeals and attitude change

The effects of fear appeals on persuasion were investigated in a factorial experiment that was designed to test a combined model of protection motivation theory and self-efficacy theory. As predicted, the probability of a threat's occurrence and the effectiveness of a coping response both had positive main effects on intentions to adopt a recommended preventive health behavior. More importantly, the findings provided support for self-efficacy expectancy as a fourth component of protection motivation theory: Self-efficacy had a direct influence on intentions and interacted with two other variables of protection motivation theory. The interaction effect was interpreted in terms of two new decision-making strategies that people use when confronted with a fear appeal: a precaution strategy and a hyperdefensiveness strategy. In addition, the results replicated previous findings on the relationship between self-efficacy expectancy and outcome expectancy. A model incorporating protection motivation theory and self-efficacy theory is presented as a possible general model of attitude change.     

‘Ideal learning’ of natural language: Positive results about learning from positive evidence

Gold's [1967. Language identification in the limit. Information and Control, 16, 447-474] celebrated work on learning in the limit has been taken, by many cognitive scientists, to have powerful negative implications for the learnability of language from positive data (i.e., from mere exposure to linguistic input). This provides one, of several, lines of argument that language acquisition must draw on other sources of information, including innate constraints on learning. We consider an ‘ideal learner’ that applies a Simplicity Principle to the problem of language acquisition. The Simplicity Principle chooses the hypothesis that provides the briefest representation of the available data—here, the data are the linguistic input to the child. The Simplicity Principle allows learning from positive evidence alone, given quite weak assumptions, in apparent contrast to results on language learnability in the limit (e.g., Gold, 1967). These results provide a framework for reconsidering the learnability of various aspects of natural language from positive evidence, which has been at the center of theoretical debate in research on language acquisition and linguistics.     

Attributing causes for one's own performance: The effects of sex,norms, and outcome

Two experiments were conducted to determine the effect of sex of subject, stated sex linkage of task, and task outcome on causal attributions of an actor's performance. Results from both studies showed that: (1) males evaluate their performance more favorably than do females, despite equivalent objective scores; (2) males claim greater ability than do females following task performance; and (3) females are more prone to use luck to explain performance. The evidence also suggests that the difference between males and females in performance evaluation and self-attribution occurs most strongly in response to failure and on masculine tasks. The results are interpreted in terms of a general expectancy model.     

The prevention of depression: Current research and practice

In 1984, a National Institute of Mental Health public information pamphlet titled Depression: What We Know stated that “In general, the onset of a clinical depression cannot be prevented” (Lobel & Hirschfeld, 1984, p. 4). This paper examines the current evidence on this question. After the scope of depression prevention research has been specified, studies focused on preventing clinical episodes of depression, preventing high symptom levels, and reducing symptom levels in high-risk groups will be reviewed. This will represent what has been done to date in terms of preventive interventions. Next, several research areas that have potential contributions to make in the quest for future depression prevention strategies will be explored.     

Hume's nominalism and the Copy Principle

I consider some ways in which the Copy Principle (CP) and Hume's nominalism impinge on one another, arguing for the following claims. First, Hume's argument against indeterminate ideas isn't cogent even if the CP is accepted. But this does not vindicate Locke: the imagistic conception of ideas, presupposed by the CP, will force Locke to accept something like Hume's view of the way general terms function, the availability of abstract ideas notwithstanding. Second, Hume's discussion of nominalism provides support for the “old Hume” interpretation, that which takes the CP to be a criterion of meaningfulness, as against the “new Hume” reading, according to which it constrains what we can know. Finally, nominalism forces Hume to adopt a more complicated theory of ideas.     

A biased random walk model for two choice reaction times

This paper generalizes Stone's (1960, Psychometrika 25, 251–260) random walk model of two choice response times (RTs) that is based on the sequential probability ratio test (SPRT) and that predicts equal correct and incorrect RTs to the same response. The generalized version allows a bias of the type found in signal detection theory to enter directly into the accumulation process so that ambivalent evidence may be seen as slightly favoring one alternative. The resulting biased SPRT model can predict any relation between correct and incorrect mean RTs. In particular, unlike the special symmetric case of Link and Heath's (1975, Psychometrika 40, 77–105) relative judgment theory (RJT), the biased SPRT model can predict that correct mean RTs are faster for one response but slower for the other. The biased SPRT model, the classical SPRT model, and the symmetric RJT model are all fit to the data of an RT deadline experiment reported by Green and Luce (1973, Attention and performance, New York: Academic Press) and it is shown that, of the three, the biased SPRT model provides the best account. Finally, a method for incorporating the same sort of bias into RJT models is sketched out.