Continuous monitoring of human contingency judgment across trials

Recent evidence suggests that people are sensitive to the degree of contingency between their actions and ensuing outcomes, but little is known about the way in which such contingency judgments develop as more and more information about the contingency is provided. Three experiments examined this issue in the context of a video game. In Experiment 1, it was found that contingency judgments follow growth functions: When the contingency was positive, judgments increased toward a positive asymptote, and when the contingency was negative, judgments decreased toward a negative asymptote. When the contingency was zero, judgments themselves remained close to zero but were biased by the overall frequency with which the outcome occurred. In Experiment 2, it was shown that the growth function was not the result of the anchoring of early judgments at the zero point. The bias in judgments when the contingency is zero was investigated in Experiment 3. The results are discussed in terms of rule-based analyses and contemporary theories of conditioning.     

Some observations on a Popperian experiment concerning observation

In several places Popper describes a little experiment in which an audience is given the non-specific command Observe! He draws a number of conclusions from this experiment, in particular that observation takes place in the presence of theoretical problems, questions, hypotheses or points of view. The paper argues that while Popper's experiment is instructive, it hardly supports the strong conclusions he draws about the theory-dominance of observation in science. In particular, it is argued that talk of principles of selection which guide us to relevant observations, rather than the host of irrelevant observations of the naive inductivist, is misleading. Rather, it is the goals, aims, motives or interests of an observer that guide observation and these need not always involve a theoretical component.     

Abstraction Processes in Artificial Grammar Learning

Four experiments explored the extent to which abstract knowledge may underlie subjects' performance when asked to judge the grammaticality of letter strings generated from an artificial grammar. In Experiments 1 and 2 subjects studied grammatical strings instantiated with one set of letters and were then tested on grammatical and ungrammatical strings formed either from the same or a changedletter-set.Evenwith a change ofletter-set, subjects were found to be sensitive to a variety of violations of the grammar. In Experiments 3 and 4, the critical manipulation involved the way in which the training strings were studied: an incidental learning procedure was used for some subjects, and others engaged in an explicit code-breaking task to try to learn the rules of the grammar. When strings were generated from a biconditional (Experiment 4) but not from a standard finite-state grammar (Experiment 3), grammaticality judgements for test strings were independent of their surface similarity to specific studied strings. Overall, the results suggest that transfer in this simple memory task is mediated at least to some extent by abstract knowledge.     

Util-izing animals

ABSTRACT Biomedical experimentation on animals is justified, researchers say, because of its enormous benefits to human beings. Sure, animals suffer and die, but that is morally insignificant since the benefits of research incalculably outweigh the evils. Although this utilitarian claim appears straightforward and relatively uncontroversial, it is neither straightforward nor uncontroversial. This defence of animal experimentation is likely to succeed only by rejecting three widely held moral presumptions. We identify these assumptions and explain their relevance to the justification of animal experimentation. We argue that, even if non-human animals have considerably less moral worth than humans, experimentation is justified only if the benefits are overwhelming. By building on and expanding on arguments offered in earlier papers, we show that researchers cannot substantiate their claims on behalf of animal research. We conclude that there is currently no acceptable utilitarian defence of animal experimentation. Moreover, it is unlikely that there could be one. Since most apologists of animal experimentation rely on utilitarian justifications of their practice, it appears that biomedical experimentation on animals is not morally justified .     

Animal experimentation: The legacy of Claude Bernard

Claude Bernard, the father of scientific physiology, believed that if medicine was to become truly scientific, it would have to be based on rigorous and controlled animal experiments. Bernard instituted a paradigm which has shaped physiological practice for most of the twentieth century. In this paper we examine how Bernard's commitment to hypothetico‐de‐ductivism and determinism led to (a) his rejection of the theory of evolution; (b) his minimalization of the role of clinical medicine and epidemiological studies; and (c) his conclusion that experiments on non‐human animals were, “entirely conclusive for the toxicology and hygiene of man”. We examine some negative consequences of Bernardianism for twentieth century medicine, and argue that physiology's continued adherence to Bernardianism has caused it to diverge from the other biological sciences which have become increasingly infused with evolutionary theory.     

Perfect MV-algebras are categorically equivalent to abelianl-groups

In this paper we prove that the category of abelianl-groups is equivalent to the category of perfect MV-algebras. Furthermore, we give a finite equational axiomatization of the variety generated by perfect MV-algebras.Presented byDaniele Mundici     

Tests of the power PC theory of causal induction with negative contingencies

The power PC theory of causal induction (Cheng, 1997) proposes that causal estimates are based on the power p of a potential cause, where p is the contingency between the cause and effect normalized by the base rate of the effect. Previous tests of this theory have concentrated on generative causes that have positive contingencies with their associated outcomes. Here we empirically test this theory in two experiments using preventive causes that have negative contingencies for their outcomes. Contrary to the power PC theory, the results show that causal judgments vary with contingency across conditions of constant power p. This pattern is consistent, however, with several alternative accounts of causal judgment.     

A case study of mediated learning, delayed auditory feedback, and motor repatterning to reduce stuttering

A case study of DW, an 11-yr. old monolingual, English-speaking boy who exhibits stuttering, language delay, and ADHD is presented. DW experienced only limited improvement during stuttering therapy received in public schools, according to parents and the public school clinician. The purpose of this case study was to assess whether fluency treatment which incorporated Mediated Learning, Delayed Auditory Feedback, and Speech Motor Repatterning would enhance progress. Therapy was delivered in two treatments, with each treatment being 5 wk. of intense therapy, separated by one year. Treatment 1 of combined Mediated Learning and Delayed Auditory Feedback yielded improvement in fluency, judged by parents and the teacher to be clinically significant. The improved fluency was maintained for one year when DW was pretested for participation in Treatment 2, which combined Mediated Learning, Delayed Auditory Feedback, and Speech Motor Repatterning Exercises. As no conclusions are possible, further study is needed.     

Intentional control and implicit sequence learning

Sequence knowledge acquired by repeated exposure to targets in a speeded localization task was studied in 3 experiments that sought to test A. Destrebecqz and A. Cleeremans's (2001, 2003) claim that, under certain circumstances, the expression of such sequence knowledge cannot be brought under intentional control. In Experiment 1 participants were trained on either a deterministic or a probabilistic sequence and then performed a free-generation test under either inclusion or exclusion instructions. Participants were found to be capable of both expressing (inclusion) and avoiding expressing (exclusion) sequence knowledge. These results were confirmed in Experiment 2 with a more exact replication of Destrebecqz and Cleeremans's methodology. In Experiment 3 participants performed a trial-by-trial generation test under both inclusion and exclusion conditions after a much longer period of training. All the findings are consistent with the proposal that information acquired during sequence learning is explicit in nature.     

The influence of hierarchy on probability judgment

Consider the task of predicting which soccer team will win the next World Cup. The bookmakers may judge Brazil to be the team most likely to win, but also judge it most likely that a European rather than a Latin American team will win. This is an example of a non-aligned hierarchy structure: the most probable event at the subordinate level (Brazil wins) appears to be inconsistent with the most probable event at the superordinate level (a European team wins). In this paper we exploit such structures to investigate how people make predictions based on uncertain hierarchical knowledge. We distinguish between aligned and non-aligned environments, and conjecture that people assume alignment. Participants were exposed to a non-aligned training set in which the most probable superordinate category predicted one outcome, whereas the most probable subordinate category predicted a different outcome. In the test phase participants allowed their initial probability judgments about category membership to shift their final ratings of the probability of the outcome, even though all judgments were made on the basis of the same statistical data. In effect people were primed to focus on the most likely path in an inference tree, and neglect alternative paths. These results highlight the importance of the level at which statistical data are represented, and suggest that when faced with hierarchical inference problems people adopt a simplifying heuristic that assumes alignment.