In Vivo Hippocampal Acetylcholine Release During Exposure to Acute Stress

Hippocampal extracellular acetylcholine (ACh) and choline levels were evaluated using in vivo microdialysis in male Fischer 344 rats before, during, and following an 80-min exposure to two different stress conditions. Measurements were taken in rats restrained and immersed in a water bath containing either 37 degreesC (normothermic-restraint) or 20 degreesC (cold-restraint) water. Results were compared to normothermic-freely-moving rats. Cold-restrained rats displayed decreased ACh levels during cold exposure relative to both normothermic-restrained and normothermic-freely-moving rats. By the end of the cold exposure period and following removal from cold, ACh levels had returned to near-baseline values. Normothermic-restrained rats had levels similar to those of normothermic-freely-moving rats, except for a marked increase in ACh following removal from restraint. Cold-restrained rats displayed a gradual elevation in choline levels during cold stress, followed by a gradual decline after stress termination, whereas both normothermic-restrained and normothermic-freely-moving rats displayed gradual decreases during the microdialysis session. These findings demonstrate that central cholinergic neurotransmission can be altered by the application of, and removal from, acute stressors. In addition, the results suggest a possible relationship between the magnitudes of both the stressor and its cholinergic consequences.     

Print adverts: Not remembered but memorable

Attempts to measure advertising effectiveness have relied on explicit memory measures based on recall or recognition. However, recent cognitive research has shown that not only is it possible to measure unconscious effects of prior experience through implicit tests of memory, but that such performance is independent of explicit recollection. The present study sought to determine whether it is possible to demonstrate the same pattern of findings using print advertising in an ecologically valid situation. Eighty subjects saw 25 full-page colour magazine adverts in either a deliberate or incidental study condition and subsequently rated (on four salient dimensions) a set of 50 adverts, which included the target adverts. Following the ratings subjects were asked to indicate which of the adverts they recognized as having been in the original set. While the deliberate study group recognized around 60 per cent of the adverts, the incidental study group recognized only 11 per cent. However, both groups showed the same positive bias in attitudes towards the adverts they had been exposed to compared to the ones they had not seen before. Thus, in line with by the cognitive literature, it is possible to show shifts in attitudes that are independent of conscious recollection. This data questions advertisers' reliance one explicit memory tests as measures of advertising effectiveness.     

A comparison of positive vicarious learning and verbal information for reducing vicariously learned fear

Research with children has demonstrated that both positive vicarious learning (modelling) and positive verbal information can reduce children's acquired fear responses for a particular stimulus. However, this fear reduction appears to be more effective when the intervention pathway matches the initial fear learning pathway. That is, positive verbal information is a more effective intervention than positive modelling when fear is originally acquired via negative verbal information. Research has yet to explore whether fear reduction pathways are also important for fears acquired via vicarious learning. To test this, an experiment compared the effectiveness of positive verbal information and positive vicarious learning interventions for reducing vicariously acquired fears in children (7–9 years). Both vicarious and informational fear reduction interventions were found to be equally effective at reducing vicariously acquired fears, suggesting that acquisition and intervention pathways do not need to match for successful fear reduction. This has significant implications for parents and those working with children because it suggests that providing children with positive information or positive vicarious learning immediately after a negative modelling event may prevent more serious fears developing.     

The Effects of Commitment to Multiple Foci: An Analysis of Relative Influence and Interactions

Recent research on employee commitment has adopted a multifoci framework, arguing that it is important to distinguish between commitments to particular targets such as supervisors, coworkers, and the organization itself. However, there remain questions about the relative importance of different commitments for predicting outcomes and about possible interactive effects among multiple commitments. To address these questions, the authors collected data from 279 employees as well as their supervisors and coworkers. The authors found robust effects for affective commitment to supervisors, showing that it was significantly related to turnover intentions, task performance, and citizenship behaviors incremental to affective commitment to the organization and coworkers. In addition, a 3-way commitment interaction predicted task performance and citizenship behaviors directed toward the supervisor.     

Aversive properties of the negative stimulus in a successive discrimination

Experiment I sought to determine if the stimulus correlated with extinction in a successive discrimination was an aversive stimulus. An escape response provided an index of aversive control. Two groups of pigeons were exposed to a multiple variable-interval 30-sec extinction schedule. For the experimental group, a single peck on a second key produced a timeout during which all lights in the chamber were dark. For the control group, pecks on the second key had no contingency. The rate of responding on the timeout key during extinction for the experimental group was higher than that of the control group during all sessions of discrimination training except the first. In Exp. II, green was correlated with variable interval 30-sec and red was correlated with variable-interval 5-min. Timeouts were obtained from variable-interval 5-min. There were more timeouts from extinction in Exp. I than from variable-interval 5-min in Exp. II. Experiment III showed that not presenting the positive stimulus reduced the number of timeouts from the negative stimulus for the two birds from Exp. I that had the highest rate of timeouts from extinction, but had little effect on the two birds that had the lowest rate of timeouts. These results suggest that in a multiple schedule, the stimulus correlated with extinction, or the lower response rate, functions as a conditioned aversive stimulus. Explanations of the timeout response in terms of extinction produced variability, displaced aggression, and stimulus change, were considered but found inadequate.