Overshadowing of a stimulus-reinforcer association by an instrumental response

In two experiments, rats were first exposed to pairings of a clicker and food; they were subsequently, in order to measure the effectiveness of the clicker as a conditioned reinforcer, given the opportunity to press a lever which turned the clicker on. For one group of animals the food originally delivered in the presence of the clicker had been contingent on their performance of an instrumental response (running in a running wheel); for a second the contingency between clicker and food had been purely classical. Although the actual correlation between clicker and food was identical for the two groups, the clicker was a less effective conditioned reinforcer for the first group than for the second. In a third experiment, all animals were initially required to run to obtain food in the presence of the clicker, but one group received additional trials on which food was delivered contingent on running in the absence of the clicker. This group showed less tendency to lever press for the clicker than a second group that had received free food on trials when the clicker was not presented. The results of all three experiments suggest that conditioning to the clicker could be overshadowed if the occurrence of food was more reliably predicted by the execution of an instrumental running response; they thus support the view that instrumental conditioning depends on the establishment of an association between response and reinforcer similar to the association between stimulus and reinforcer underlying classical conditioning.     

Drugs, Morality and the Law

Arguments for and against the legal prohibition of drugs are surveyed. Various kinds of argument are identified and analysed: arguments against prohibition from a moral right to personal liberty; utilitarian and contractualist arguments for a right to personal liberty; arguments for prohibition from liberty–limiting principles (the harm principle, legal paternalism, legal moralism, Kantian duties to oneself, legal perfectionism, traditional conservatism, and communitarianism); utilitarian argument for prohibition; utilitarian argument against prohibition. It is concluded that none of the arguments for drug prohibition is convincing.     

The Role of Attachment Styles and Interpersonal Problems in Suicide‐Related Behaviors

The relationships among adult attachment styles, interpersonal problems, and categories of suicide‐related behaviors (i.e., self‐harm, suicide attempts, and their co‐occurrence) were examined in a predominantly psychiatric sample (N = 406). Both anxious and avoidant attachment styles were associated with interpersonal problems. In turn, specific interpersonal problems differentially mediated the relations between attachment style and type of suicide‐related behaviors. These findings suggest the importance of distinguishing between these groups of behaviors in terms of etiological pathways, maintenance processes, and treatment interventions.     

Age and Trust as Moderators in the Relation between Procedural Justice and Turnover: A Large‐Scale Longitudinal Study

The current study investigated the moderating roles of age and trust in the relation of procedural justice with turnover. It was expected that the relation between procedural justice and turnover was weaker for older workers and those with high prior trust in their leader. Older workers are better at regulating their emotions, and focus more on positive aspects of their relationships with others, and therefore react less intensely to unfair treatment. Moreover, people with high trust are more likely to attribute unfair treatment to circumstances instead of deliberate intention than people with low trust. Finally, we expected a three‐way interaction between age, trust, and procedural justice in relation to turnover, where older workers with high trust would have less strong reactions than younger workers and older workers with low trust. Results from a three‐wave longitudinal survey among 1,597 Dutch employees indeed revealed significant interactions between trust and procedural justice in relation to turnover. Furthermore, the three‐way interaction was significant, with negative relations for younger workers, but a non‐significant relation was found for older workers with low trust. Contrary to expectations, negative relations were found between procedural justice and turnover for older workers with high trust.