Effects of Acute Stress or Centrally Injected Interleukin-1beta on Neuropeptide Expression in the Immune System

Acute stress stimulates the expression and release of corticotropin-releasing hormone (CRH) and arginine vasopressin (AVP) from the hypothalamus, and the pro-opiomelanocortin products beta-endorphin and ACTH from the anterior pituitary. These neuropeptides are also expressed in immune tissues, and it has been proposed that they may modulate immune responses to stress through paracrine mechanisms. We subjected rats to restraint stress or central injection of interleukin (IL)-1beta to determine whether these acute stimuli can alter the expression of neuropeptides in the spleen and thymus. Restraint stress significantly increased the contents of all these neuropeptides in thymic, but not splenic, extracts. A single icv injection of IL-1beta increased contents of CRH, AVP, ACTH and beta-endorphin in the spleens of both sham-operated and adrenalectomised (ADX) rats. IL-1beta increased thymic contents of CRH and ACTH in sham-operated rats but these increases were not observed in ADX rats. These results suggest that the effects of IL-1beta on neuropeptide expression in the spleen are independent of glucocorticoids, whereas IL-1beta stimulation of neuropeptide expression in the thymus is dependent on circulating glucocorticoids. There were significant correlations between increases in CRH, ACTH and beta-endorphin in the spleen, and between CRH and ACTH in the thymus, consistent with the suggestion that IL-1beta-induced increases in ACTH and beta-endorphin may be mediated through CRH. These results provide evidence that stressors can directly influence neuropeptide expression in immune tissues. Thus stress may influence immune functions through paracrine mechanisms involving locally synthesised neuropeptides as well as through activation of the hypothalamo-pituitary-adrenal axis.     

Attending to the big picture: mood and global versus local processing of visual information

Two experiments employed image-based tasks to test the hypothesis that happier moods promote a greater focus on the forest and sadder moods a greater focus on the trees. The hypothesis was based on the idea that in task situations, affective cues may be experienced as task-relevant information, which then influences global versus local attention. Using a serial-reproduction paradigm, Experiment 1 showed that individuals in sad moods were less likely than those in happier moods to use an accessible global concept to guide attempts to reproduce a drawing from memory. Experiment 2 investigated the same hypothesis by assessing the use of global and local attributes to classify geometric figures. As predicted, individuals in sad moods were less likely than those in happier moods to classify figures on the basis of global features.     

Analyzing anger: how to make people mad

Does simple displeasure cause anger without appraisals or agency attributions? The authors offer 8 observations: (a) Appraisal theory also predicts that displeasure promotes anger, (b) An emotion of frustration can be usefully distinguished from anger, (c) Aggressive reactions to norm violations among animals suggest that they too distinguish bad behavior from bad outcomes, (d) Attributions to agency are perceptual and automatic in social situations, (e) It is tenuous to argue that agency attributions are enacted in angry aggression, but absent in anger elicitation. (f) The contextualized meanings of expressive movements, rather than movements themselves, elicit emotion, (g) Expressions may be better seen as constituents than as causes of emotions, (h) Cognitive components of emotion generally come before, not after, eliciting events.     

Do approach-avoidance actions create attitudes?

Do approach-avoidance actions create attitudes? Prior influential studies suggested that rudimentary attitudes could be established by simply pairing novel stimuli (Chinese ideographs) with arm flexion (approach) or arm extension (avoidance). In three experiments, we found that approach-avoidance actions alone were insufficient to account for such effects. Instead, we found that these affective influences resulted from the interaction of these actions with a priori differences in stimulus valence. Thus, with negative stimuli, the effect of extension on attitude was more positive than the effect of flexion. Experiment 2 demonstrated that the affect from motivationally compatible or incompatible action can also influence task evaluations. A final experiment, using Chinese ideographs from the original studies, confirmed these findings. Both approach and avoidance actions led to more positive evaluations of the ideographs when the actions were motivationally compatible with the prior valence of the ideographs. The attitudinal impact of approach-avoidance action thus reflects its situated meaning, which depends on the valence of stimuli being approached or avoided.     

Does stress enhance or impair memory consolidation?

Three experiments examined the hypothesis that stress-induced arousal enhances long-term memory for experiences associated with arousing events. Contrary to expectations, in each experiment exposure to a stressor (arm immersion in ice water) interfered with, rather than enhanced, long-term memory for associated material. Despite varying the stimuli (words, pictures), their emotional value (positive, negative, neutral), the time between learning and stress inductions (0 to 1 minute), and opportunities for post-learning rehearsal, each experiment produced a significant reversal of the hypothesised effect. That is, in each experiment, exposure to a stressor interfered with, rather than enhanced, long-term memory for associated material. We conclude that the relationship between stress and memory consolidation is more bounded than previously believed.     

Affective facilitation and inhibition of cultural influences on reasoning

Research in South Korea and the United States examined how affective states facilitate or inhibit culturally dominant styles of reasoning. According to the affect-as-information hypothesis, affective cues of mood influence judgements by serving as embodied information about the value of accessible inclinations and cognitions. Extending this line of research to culture, we hypothesised that positive affect should promote (and negative affect should inhibit) culturally normative reasoning. The results of two studies of causal reasoning supported this hypothesis. Positive and negative affect functioned like “go” and “stop” signals, respectively, for culturally typical reasoning styles. Thus, in happy (compared to sad) moods, Koreans engaged in more holistic reasoning, whereas Americans engaged in more analytic reasoning.     

Dissimilarity and attraction: when difference makes a difference.

Students in 93 university classes described themselves and their instructors on personality tests measuring traits relevant (ascendancy and personal relations) and irrelevant (sociability and cautiousness) to teaching skill. Dissimilarity (instructor being higher than student) on relevant trait dimensions was hypothesized to be instrumental for student satisfaction with an instructor's role performance. When students were classified as similar or dissimilar to their instructors on the personality dimensions, those most attracted to their instructors were those dissimilar on relevant (but not irrelevant) traits. The dissimilarity finding was not an artifact of differences in skill of instructor nor of differences in students' perceptions of their instructors' traits. A three-dimensional system was devised to specify when similarity and dissimilarity should promote attraction.     

Helping on the Highway: The Effects of Dependency and Sex1

A series of three naturalistic field experiments are reported which investigated the norm of social responsibility by examining the effects of dependency and sex on helping. Experiment I examined the effect of physical disability on the likelihood of passing motorists helping with a flat tire. Females were helped significantly more than males, but the dependency manipulation was only minimally effective. In Experiment II the same disability cues were used in a hitchhiking context. Again females were helped significantly more than males, but surprisingly the dependency cues significantly reduced the number of ride offers. Experiment III used hitchhiking as the behavior of interest, but this time the dependency cues involved a disabled vehicle. This dependency manipulation significantly increased help offers. In addition, females were again helped significantly more than males. In all three experiments, almost all help offers were made by males. Other variables that appeared to influence helping rates were the perceived cost of helping, the attractiveness of the solicitors, and whether they were seen as responsible for their state of dependency. The present field results complemented previous laboratory work on the Same variables.     

Disgust as embodied moral judgment

How, and for whom, does disgust influence moral judgment? In four experiments participants made moral judgments while experiencing extraneous feelings of disgust. Disgust was induced in Experiment 1 by exposure to a bad smell, in Experiment 2 by working in a disgusting room, in Experiment 3 by recalling a physically disgusting experience, and in Experiment 4 through a video induction. In each case, the results showed that disgust can increase the severity of moral judgments relative to controls. Experiment 4 found that disgust had a different effect on moral judgment than did sadness. In addition, Experiments 2-4 showed that the role of disgust in severity of moral judgments depends on participants' sensitivity to their own bodily sensations. Taken together, these data indicate the importance-and specificity-of gut feelings in moral judgments.     

Skating down a steeper slope: fear influences the perception of geographical slant

Previous studies have shown that conscious awareness of hill slant is overestimated, but visually guided actions directed at hills are relatively accurate. Also, steep hills are consciously estimated to be steeper from the top than the bottom, possibly because they are dangerous to descend. In the present study, participants stood at the top of a hill either on a skateboard or a wooden box of the same height. They gave three estimates of the slant: a verbal report, a visually matched estimate, and a visually guided action. Fear of descending the hill was also assessed. Those participants who were scared (by the skateboard) consciously judged the hill to be steeper than unafraid participants. However, the visually guided action measure was accurate across conditions. These results suggest that explicit awareness of slant is influenced by the fear associated with a potentially dangerous action that could be performed on the hill.