Peripheral control of drinking: gastrointestinal filling as a negative feedback signal, a theoretical and experimental analysis.

The studies described here investigated the hypothesis that the osmotic postingestional satiety signal proposed by McCleary operates through a mechanism related to gut filling rather than by osmotically induced shifts of fluid from osmoreceptors in the brain. A control theory model is presented, which was designed to make quantitatively explicit the hypothesis under question. The results showed that when mannitol, which is not absorbed from the intestine, is added to a highly palatable saccharin-glucose mixture, the amount of fluid consumed decreased in inverse proportion to the mannitol concentration. Mannitol was also shown to block fluid absorption from the intestine at a low concentration (approximately .070 M) and at higher concentrations to lead to a net flux of fluid into the intestinal lumen. It was also shown that mannitol in concentrations that reduced the intake of the palatable solution did not induce thirst when the animals were in water balance. It did induce thirst, however, when the animals were tested in a state of negative water balance. The results of these studies, considered as a whole, support the view that McCleary's osmotic postingestional satiety signal acts as an intestinal distention signal rather than by inducing thirst. The model is found to be reasonably accurate as a first approximation, and suggestions are made for improvements.     

Audience reaction as a determinant of the speaker's self-persuasion

This paper tests effects of audience feedback on speaker attitudes. One hundred and seven male subjects with initial beliefs on both sides of an issue (women's role) were assigned to speak for or against their own position; then an “audience” provided one of three types of feedback (speaker was sincere, speaker was insincere, no feedback) in a 2 × 2 × 3 design. Subjects who received sincere feedback showed greater change in the direction of their speech than did those who received insincere feedback. No feedback treatments resulted in intermediate change. This sincere > no feedback > insincere ordering of means held for both pro- and counterattitudinal speakers and for both pretest attitudes. A main effect for pretest attitude was also obtained. Two additional control groups allow for a separate analysis of the effects of (1) preparing and delivering the speech, and (2) audience reaction to the speech.     

The excess choice effect: The role of outcome valence and counterfactual thinking

Contrary to economic theory, psychological research has demonstrated increased choice can undermine satisfaction. When and why this ‘excess choice effect’ (ECE) occurs remains unclear. Building on theories of counterfactual thinking we argue the ECE is more likely to occur when people experience counterfactual thought or emotion and that a key trigger is a negative versus positive task outcome. Participants either selected a drink (Experiment 1) or chocolate (Experiment 2) from a limited (6) versus extensive (24) selection (Experiment 1) or were given no choice versus extensive (24) choice (Experiment 2). In both experiments, however, the choice was illusory: Half the participants tasted a ‘good’ flavour, half a ‘bad’ flavour. As predicted, extensive choice was only detrimental to satisfaction when participants tasted the ‘bad’ drink or chocolate, and this was mediated by the experience of counterfactual thought (Experiment 1) or emotion (Experiment 2). When outcomes were positive, participants were similarly satisfied with limited versus extensive and no choice versus extensive choice. Implications for our theoretical understanding of the ECE and for the construction of choice architectures aimed at promoting individual satisfaction and well‐being are discussed.     

Intergenerational Transmission of Trauma-Related Distress: Maternal Betrayal Trauma,Parenting Attitudes,and Behaviors

The purpose of this study was to elucidate mechanisms involved in the intergenerational transmission of trauma-related distress. This study investigated whether betrayal trauma (BT; abuse by a person close to the victim) and specific parenting attitudes and behaviors among mothers with child abuse histories predicted internalizing and externalizing symptoms in their children. Mothers and children (ages 7–11) were recruited for a project on parenting and stress (N = 72). Maternal betrayal trauma predicted both internalizing (β = 0.33, p < .01) and externalizing symptoms (β = 0.25, p < .05) even when controlling for mothers’ trauma-related symptoms. Negative attitudes toward limit setting predicted externalizing symptoms (β = ?0.33, p < .05). Poorer communication (β = ?0.39, p < .05) but higher parenting satisfaction (β = 0.38, p < .01) predicted internalizing symptoms. These findings demonstrate the importance of assessing maternal trauma and parenting characteristics as part of interventions with symptomatic children.     

When clinical care is like research: the need for review and consent

The prevailing “segregated model” for understanding clinical research sharply separates it from clinical care and subjects it to extensive regulations and guidelines. This approach is based on the fact that clinical research relies on procedures and methods—research biopsies, blinding, randomization, fixed treatment protocols, placebos—that pose risks and burdens to participants in order to collect data that might benefit all patients. Reliance on these methods raises the potential for exploitation and unfairness, and thus points to the need for independent ethical review and more extensive informed consent. In contrast, it is widely assumed that clinical care does not raise these ethical concerns because it is designed to promote the best interests of individual patients. The segregation of clinical research from clinical care has been largely effective at protecting research participants. At the same time, this approach ignores the fact that several aspects of standard clinical care, such as clinician training and scheduling, also pose some risks and burdens to present patients for the benefit of all patients. We argue that recently proposed learning health care systems offer a way to address this concern, and better protect patients, by developing integrated review and consent procedures. Specifically, current approaches base the need for independent ethical review and more extensive informed consent on whether an activity is categorized as clinical research or clinical care. An ethically sounder approach, which could be incorporated into learning health care systems, would be to base the need for independent ethical review and more extensive informed consent on the extent to which an activity poses risks to present patients for the benefit of all patients.     

Effects of environmental enrichment on cognitive performance of pigs in a spatial holeboard discrimination task

This study investigated the effects of environmental enrichment on the cognitive performance of female conventional farm (growing) pigs in a spatial holeboard task. Ten pairs of littermates matched for weight were used. From each litter, one piglet was randomly assigned to a barren environment; the other was assigned to an enriched environment from 4 weeks of age. The enriched environment was double the size of the barren environment, had a floor covered with straw, a rooting area filled with peat, and one of the four different enrichment toys which were exchanged daily. Starting at 11 weeks of age, all pigs were tested in a spatial holeboard discrimination task in which 4 out of 16 holes were baited. Furthermore, basal salivary cortisol levels of all pigs were determined after the end of all testing. All pigs were able to acquire the pattern of baited holes (acquisition phase, 40 trials) and the diagonally mirrored pattern (reversal phase, 20 trials). During the acquisition phase, the reference memory performance of the enriched-housed pigs was better than that of their barren-housed littermates, i.e. they reduced visits to the unbaited set of holes. During the reversal phase, enriched-housed pigs had a better general working memory performance than the barren-housed pigs as indicated by reduced revisits to holes already visited during a trial, irrespective of whether they were of the baited or the unbaited set. The enriched-housed pigs also searched for the hidden bait faster during both phases. The environments did not affect basal salivary cortisol levels. In conclusion, environmental enrichment slightly improved the cognitive performance of pigs in a spatial learning task. We hypothesise that the long period of habituation to and testing in the holeboard acted as enrichment that partially reduced the effects of barren housing.