Barbara C. N. Müller

Hydrogen uptake by MoS2 and sulfided alumina-supported Mo catalysts

Volumetric H2-uptake measurements on polycrystalline MoS2 (39 m2g−1) have been carried out and uptake isotherms in the temperature range 423–573 K have been determined. The equilibrium stoichiometry at 500 mbar and 573 K was H0.035MoS2, and at 473 K the HMo ratio increased to 0.051. Alumina-supported sulfided Mo catalysts provided HMo ratios that were higher by approximately a factor of 4, indicating either a higher MoS2 surface area, spillover of H atoms to the support, or both. Two possible mechanisms for H2 dissociation are discussed, namely, heterolytic dissociation on MoS pairs and homolytic dissociation on disulfide (SS)2− edge groups. The presence of the latter on MoS2 is documented by Raman spectroscopy which shows the characteristic v(SS) mode at 529 cm−1. Although molecular analogs for H2 activation on disulflde groups are known, it is not yet possible to make a clear distinction between the alternative H2 dissociation routes.

Why do I like you when you behave like me? Neural mechanisms mediating positive consequences of observing someone being imitated.

Social psychological and developmental research revealed that imitation serves a fundamental social function. It has been shown that human beings have the tendency to automatically mirror the behavior of others—the so-called chameleon effect. Furthermore, it has been demonstrated that being imitated leads to positive feelings toward the imitator. But why do we feel more positive about someone who imitates us? In the current fMRI study we aimed at exploring the neural correlates of the positive consequences of being imitated by means of an observation paradigm. Our results indicate that being imitated compared to not being imitated activates brain areas that have been associated with emotion and reward processing, namely medial orbitofrontal cortex/ventromedial prefrontal cortex (mOFC/vmPFC, GLM whole-brain contrast). Moreover mOFC/vmPFC shows higher effective connectivity with striatum and mid-posterior insula during being imitated compared to not being imitated.

Perspective taking eliminates differences in co-representation of out-group members’ actions

Coordinated action relies on shared representations between interaction partners: people co-represent actions of others in order to respond appropriately. However, little is known about the social factors that influence shared representations. We investigated whether actions performed by in-group and out-group members are represented differently, and if so, what role perspective-taking plays in this process. White participants performed a joint Simon task with an animated image of a hand with either white or black skin tone. Results of study I demonstrated that actions performed by in-group members were co-represented while actions of out-group members were not. In study II, it was found that participants co-represented actions of out-group members when they had read about an out-group member and to take his perspective prior to the actual experiment. Possible explanations for these findings are discussed.

Neural correlates of emotional synchrony

Facial expressions can trigger emotions: when we smile we feel happy, when we frown we feel sad. However, the mimicry literature also shows that we feel happy when our interaction partner behaves the way we do. Thus what happens if we express our sadness and we perceive somebody who is imitating us? In the current study, participants were presented with either happy or sad faces, while expressing one of these emotions themselves. Functional magnetic resonance imaging was used to measure neural responses on trials where the observed emotion was either congruent or incongruent with the expressed emotion. Our results indicate that being in a congruent emotional state, irrespective of the emotion, activates the medial orbitofrontal cortex and ventromedial prefrontal cortex, brain areas that have been associated with positive feelings and reward processing. However, incongruent emotional states activated the dorsolateral prefrontal cortex as well as posterior superior temporal gyrus/sulcus, both playing a role in conflict processing.

Warning labels formulated as questions positively influence smoking-related risk perception

Research on warning labels printed on cigarette packages has shown that fear inducing health warnings might provoke defensive responses. This study investigated whether reformulating statements into questions could avoid defensive reactions. Smokers were presented with either warning labels formulated as questions, textual warning labels, graphic warning labels, or no warning labels. Participants’ smoking-related risk perception was higher after exposure to warning labels formulated as questions or no warning labels than after exposure to textual or graphic warning labels. These results indicate that reformulating statements into questions can avoid defensive responses elicited by textual- and graphic warning labels.

Prosocial Consequences of Imitation

Research has shown that helping behavior can be primed easily. However, helping decreases significantly in the presence of inhibition cues, signaling high costs for the executor. On the other hand, multiple studies demonstrated that helping behavior increases after being mimicked. The present study investigated whether imitation still increases helping when more substantial costs are involved. Helping behavior was operationalized as the willingness to accompany the confederate on a 15–20 minute walk to the train station. Results show that even in the face of these high costs, participants who were mimicked agreed more often to help the confederate than participants who were anti-mimicked. These findings suggest that mimicry not only makes people more helpful when it comes to small favors, but also allows them to ignore the substantial costs possibly involved in helping others.

Tell me why... The influence of self-involvement on short term smoking behaviour.

Previous studies found that information is more persuasive when self-generated (high self-involvement), rather than when simply read or heard (low self-involvement). In two studies, we investigated whether differences in self-involvement concerning smoking issues would influence immediate smoking behaviour. As predicted, results indicate that participants who developed their own arguments against smoking waited longer before lighting up a cigarette than those who read arguments against smoking that were developed by other participants (Study 1). Further, participants who additionally generated their own arguments were less likely to smoke within 30 min than those who read prepared arguments against smoking (Study 2). In sum, our studies illustrate that personal involvement in generating anti-smoking arguments can reduce short term smoking behaviour.

Smoking-related warning messages formulated as questions positively influence short-term smoking behaviour

Research demonstrated that by reformulating smoking warnings into questions, defensive responses in smokers are reduced and smoking-related risk perception increases. We explored whether these positive outcomes can be generalised to actual behaviour. Participants saw either a movie presenting subheadings with smoking-related questions or statements. Afterwards, the time was measured until participants lit their first cigarette. Smokers who were presented with questions about the harms of smoking waited longer before lighting up a cigarette than smokers who were presented with statements. Presenting questions instead of the statements seems to be an effective means to prolonging smokers’ abstinence.

Long-term stability in children’s frontal EEG alpha asymmetry between 14-months and 83-months

In the present study, we investigated the test‐retest stability of resting state alpha asymmetry in 18 children (9 male and 9 female) in a longitudinal design. Childrens resting state brain activation asymmetries were assessed by means of EEG first after 14 months of age, and again a second time at 83 months of age, and frontal (AsymF), temporal (AsymT), and parietal (AsymP) alpha activation asymmetries were calculated. Analyses demonstrate positive relations between frontal asymmetry scores at 14 and 83 months of age. Temporal and parietal asymmetries did not show this stability over time. This finding provides further support for the use of frontal alpha asymmetry measures to investigate processes underlying emotion and motivation in childhood, and its stability over time.

Implicit associations and compensatory health beliefs in smokers: Exploring their role for behaviour and their change through warning labels

OBJECTIVES Smokers might think that the negative effects of smoking can be compensated for by other behaviours, such as doing exercise or eating healthily. This phenomenon is known as compensatory health beliefs (CHBs). Graphic warning labels on cigarette packets emphasize the negative effects of smoking, which may impact CHBs. Research so far has assessed CHBs explicitly only via questionnaires, although implicit cognition might be an important factor in continuing to smoke. This study investigated the impact of graphic warning labels on CHBs, by testing CHBs both implicitly and explicitly. DESIGN The study had a three-group experimental design. ANOVAs and multiple regression analyses were run on the results. METHODS We assessed explicit CHBs among non-smokers, smokers, and smokers confronted with graphic warning labels (N = 107; 47 females, 23.89 years old, 78 daily smokers). Implicit associations between smoking and CHB-specific behaviours (e.g., eating healthy food) were measured using a Single-Target Implicit Association Test. After the experiment, participants were able to choose between a healthy and unhealthy food reward. RESULTS Non-smokers and smokers differed in explicit CHBs but not in implicit cognitions. Warning labels influenced implicit associations among smokers but did not affect explicit CHBs. Most interestingly, implicit associations and explicit CHBs predicted food choice and smoking among smokers not confronted with warning labels. CONCLUSIONS Graphic warning labels could be used in interventions to inhibit automatic associations between smoking and healthy behaviours. Unlearning implicit cognitions might in turn affect explicit CHBs, thus decreasing their role in reducing the negative feelings caused by smoking.