Neuroendocrine hemisphere asymmetries: Salivary cortisol secretion during lateralized viewing of emotion-related and neutral films

The study set out to examine whether the cerebral hemispheres differ in their ability to regulate cortisol secretion during emotion-related situations. One hundred twenty-three adult subjects were shown either an emotionally aversive or a neutral film in the left or right hemisphere by means of a technique for lateralizing visual input that allows prolonged viewing while permitting free ocular scanning. The film-related changes of cortisol secretion were determined by salivary cortisol radioimmunoassay. Right hemispheric viewing of the emotionally aversive film resulted in a significantly higher increase of cortisol secretion than left hemispheric viewing of the same film. No such differences were observed with respect to the neutral film. Comparing the effects of the two films separately for each hemisphere revealed that only the right hemisphere was able to respond neuroendocrinologically in a different manner to the emotional and the neutral film. Therefore, it is concluded that cortical regulation of cortisol secretion in emotion-related situations is under primary control of the right hemisphere. The potential implications of asymmetric control of cortisol secretion with respect to the pathogenesis of psychosomatic and immunological disorders are discussed.     

Exposure effects and associative learning

The contributions of initial stimulus affect and of associative learning to the effects of repeated stimulus exposures were examined in two experiments. Stimuli that were initially positive and stimuli that were initially negative were presented for different number of times, and subjects rated these stimuli afterward on a number of affective dimensions. In all cases, except when negative affect was associatively paired with every stimulus exposure, affective responses became increasingly more positive with increasing exposures. The results were taken to indicate that the exposure effect can overcome an initially negative stimulus affect when the conditions of the mere exposure hypothesis are satisfied. Initial stimulus affect and associative learning of affect were shown to be independent factors, the first influencing the intercept of the exposure function, the second its slope.     

Ambient Green and Creativity

This research examined an important applied question: whether viewing ambient green (relative to red) on the wall of a workspace would facilitate creativity. A methodologically sound experiment revealed no influence of green on creativity. Care must be taken when interpreting a null result, but these data do not provide support for the presence of a relation between ambient green and creativity. This research also highlights the need for more research in the area of ambient color and psychological functioning, and the need for caution regarding the tendency to move to real-world recommendations before a firm empirical base is established.     

Quantifying disablers in reasoning with universal and existential rules

People accept conclusions of valid conditional inferences (e.g., if p then q, p therefore q) less, the more disablers (circumstances that prevent q to happen although p is true) exist. We investigated whether rules that through their phrasing exclude disablers evoke higher acceptance ratings than rules that do not exclude disablers. In three experiments we re-phrased content-rich conditionals from the literature as either universal or existential rules and embedded these rules in Modus Ponens and Modus Tollens inferences. In Experiments 2 and 3, we also used abstract rules. The acceptance of conclusions increased when the rule was phrased with “all” instead of “some” and the number of disablers had a higher impact on existential rules than on universal rules. Further, the effect of quantifier was more pronounced for abstract rules and when tested within subjects. We discuss the relevance of phrasing, quantifiers and knowledge on reasoning.     

Common mechanisms in error monitoring and action effect monitoring

In the present study, we considered error-related brain activity in event-related potentials, to investigate the relationship between error monitoring—that is, the detection and evaluation of erroneous responses—and action effect monitoring—that is, monitoring of the sensory consequences of behavior. To this end, participants worked on a task-switching paradigm that consisted of a free-choice task, in which a puzzle piece had to be attached to an existing one (the prime task), and a subsequent color flanker task (the probe task). We examined whether unexpected action effects in the prime task would affect the subsequent error monitoring in the probe task. We found the neural correlates of error monitoring during the probe task, the error-related negativity as well as the error positivity, to be increased after unexpected action effects in the prime task. In contrast, the neural correlates of visual attention were decreased after unexpected action effects, in line with recent findings on an attenuation of sensory processing after errors. Our results demonstrate a direct link between monitoring processes in the two tasks. We propose that both error monitoring and action effect monitoring rely on a common generic monitoring system related to novelty detection or affective processing. Preactivating this system by means of unexpected action effects increases the sensitivity for detecting an error in the subsequent task.