Preference and response suppression under different correlations between shock and a positive reinforcer in rats

A lever-press response by rats was reinforced by food in two successively presented types of trial signalled by different discriminative stimuli. When responding was punished by a shock in one type of trial, a groups for which the shock always preceded the reinforcer by .5 sec (positive correlation) showed less suppression in those trials than a group which received the shock and food separated in time (negative correlation). When, in a second experiment, rats were given a choice between food alone in one end of a shuttle box and either positively or negatively correlated shock and food in the other on a concurrent schedule, the group receiving the negatively correlated shock showed a greater preference for the food alone end. On the basis of a third experiment in which a tone was substituted for the shock in the choice situation, it was argued that the effect of correlation was not simply due to the stimulus properties of the shock. A final experiment demonstrated that when shock punishment is administered during extinction of the lever-press response, the rate of extinction is slower if the shock has been previously paired with the food reinforcer. Pairing a shock with food seems to attenuate the intrinsic aversiveness of the shock through Pavlovian counterconditioning.     

Choice reaction performance following an error

Some data are presented showing the changes in choice-reaction time (CRT) and the probability of error (PE) on the five trials following an error in a two-choice experiment. The magnitudes of the increase in RT and the decrease in PE are different according as the error-trial stimulus is re-presented or the alternative stimulus is preservec. In addition, RT is quicker to recover its equilibrium value than is PE.This pattern of changes implicates two distinct adjustments to the underlying decision process following an error: (i) a selective outward adjustment of the boundary at which the error was uttered, and (ii) a delay, with respect to presentation of the reaction stimulus, of the epoch at which the subject begins sampling information from the stimulus display. When these ideas are concatenated with the sequential probability-ratio-test model for CRT, a theoretical relation can be derived between the difference in mean RT for an error and for the same response given correctly, on the one hand, and the decrease in PE on the trial following an error, given that the alternate stimulus is presented, on the other. This relation is satisfied by the data.     

Perceptual centres for Dutch digits

In two experiments, analogous to those reported by Marcus (1976) with English words and subjects, we determined the psychological moment of occurrence (p-centre) of Dutch digit names. In the first experiment we determined the p-centres for the digits 1 through 10 and compared the empirical results with values calculated from the formula that Marcus defines over the acoustic characteristics of stimulus words. We found good agreement between empirical and predicted values. In a second experiment we studied the effect of cycle time and repeated measurement on perceptual centres. The results confirm the independence of the p-centre phenomenon from practice and periodicity. A comparison of ‘identical’ and ‘non-identical’ stimulus pairs shows that larger variances are associated with the former condition.     

Causes or Cures: What makes us think of attention issues as disorders?

Are attention issues disorders or not? Philosophers of medicine have tried to address this question by looking for properties that distinguish disorders from non-disorders. Such properties include deviation of a statistical norm, a loss of function or experienced suffering. However, attempts at such conceptual analysis have not led to a consensus on the necessary and sufficient conditions for the application of the concept of disorder. Recently, philosophers have proposed an experimental approach to investigate in which circumstances people think a specific concept is applicable. Here we present a quantitative vignette study investigating whether disorder attribution depends on the perceived cause and the perceived type of treatment for an attention problem. The results of our study indicate that the attribution of a disorder decreased when the attention problem was understood as caused by bullying (social environmental cause) or by an accident (non-social environmental cause) rather than a genetic cause. When prescribed a pill, attention problems were considered a disorder to a larger extent than when the child was prescribed an environmental treatment. Our study also suggests that whereas successful environmental treatments will not necessarily decrease the disorder attribution, successful pharmacological treatments will decrease the likelihood that a person is thought to still suffer from a disorder after receiving the treatment.     

风死不救与医疗欠费——临床医德悖论及其化解

本文分析了一民工重伤求治,被六家医院拒收的事件,指出在实行临床医德准则过程中存在着悖论现象,并阐述临床医德悖论产生的原因,提出化解临床医德悖论具体的途径。     

The Tacit–Explicit Connection: Polanyian Integrative Philosophy and a Neo-Polanyian Medical Epistemology

The purpose of this paper is to introduce an approach to clinical practice aiming to resolve the dilemma of choosing between a mechanistic and a phenomenological model. The approach is an extension of Polanyi's epistemology. Michael Polanyi (1891–1976), devised an epistemology of science which overcomes the problem of detachment, inherent in the mechanistic approach, and resolves the problem of subjectivity troubling phenomenologists. His epistemology is known as Personal Knowledge. An extension of this epistemology, a Neo-Polanyian proposal, is offered as a more successful model for clinical practice than previous suggestions addressing the dilemma.     

The Role of Rhetoric in Rational Argumentation

The structure of this discussion will be tripartite. First it will set out a way of distinguishing between rhetoric and strictly rational argumentation. Next it will consider some of the ramifications of this proposed way of looking at the matter – in particular what its implications are for rationality and for rhetoric, respectively. Finally it examines how this perspective bears on the project of philosophizing. The paper's ultimate aim, accordingly, is to consider what light such an analysis can shed upon philosophy and philosophizing.     

Some aspects of eloquence in Descartes's works

In Descartes's philosophy, communicating scientific and philosophical truth does not represent a problem that can be traced back to humanistic rhetoric, meant as the art of persuasion. Descartes states his belief in the eloquence of reason: a clear, precise, and adequately expressed thought cannot fail to convince the listener. This is the measure of the distance between the level of truth and the level of opinion. However, the moment of confrontation with the public is also the very moment when the truth of the new knowledge enters into conflict with other, different conceptions. Education and history influence communication with the result that the distinction between intellectual conviction and persuasion becomes less straightforward. Rational eloquence, as Descartes is well aware, must be articulated in such a way as to avoid any possible language equivocation and to adopt exposition strategies ensuring effective access to readers. The aim of this paper is to illustrate some aspects of this tension as expressed by the writer Descartes with reference to a number of texts (from the Regulae to the Meditationes) that were essential for the elaboration and dissemination of his philosophy.     

Human vs. supervised machine learning: Who learns patterns faster?

The capabilities of supervised machine learning (SML), especially compared to human abilities, are being discussed in scientific research and in the usage of SML. This study provides an answer to how learning performance differs between humans and machines when there is limited training data. We have designed an experiment in which 44 humans and three different machine learning algorithms identify patterns in labeled training data and have to label instances according to the patterns they find. The results show a high dependency between performance and the underlying patterns of the task. Whereas humans perform relatively similarly across all patterns, machines show large performance differences for the various patterns in our experiment. After seeing 20 instances in the experiment, human performance does not improve anymore, which we relate to theories of cognitive overload. Machines learn slower but can reach the same level or may even outperform humans in 2 of the 4 of used patterns. However, machines need more instances compared to humans for the same results. The performance of machines is comparably lower for the other 2 patterns due to the difficulty of combining input features.     

Efficiency and interactions of alerting,orienting and executive networks: The impact of imperative stimulus type

The Attention Network Test (ANT) generates measures of three attention networks: alerting, orienting and executive control. Arrows have been generally used as imperative stimuli in the different versions of this paradigm. However, it is unknown whether the directional nature of these stimuli can modulate the efficiency of the executive control and its interaction with alerting and orienting. We developed three ANT variants to examine attentional effects in response to directional and non-directional stimuli. Arrows (ANTI-A), colored fruits (ANTI-F) and black geometrical-shape (ANTI-G) were used as imperative stimuli (i.e., flanker stimuli). Data collected from fifty-two university students, in two experiments, showed that arrows stimuli produced a greater interference effect and a greater orienting effect as compared to the other stimuli. Moreover, only arrows modulated the interaction between executive control and orienting: a reduced flanker effect in spatially cued trials was only observed in ANTI-A. These results suggest that the directional value of the stimuli increases the conflict and modulates the efficiency of executive control and its interaction with orienting network.