Infusing pleasure: Mood effects of the consumption of a single cup of tea.

Tea has historically been associated with mood benefits. Nevertheless, few studies have empirically investigated mood changes after tea consumption. We explored immediate effects of a single cup of tea up to an hour post-consumption on self-reported valence, arousal, discrete emotions, and implicit measures of mood. In a parallel group design, 153 participants received a cup of tea or placebo tea, or a glass of water. Immediately (i.e. 5 min) after consumption, tea increased valence but reduced arousal, as compared to the placebo. There were no differences at later time points. Discrete emotions did not differ significantly between conditions, immediately or over time. Water consumption increased implicit positivity as compared to placebo. Finally, consumption of tea and water resulted in higher interest in activities overall and in specific activity types compared to placebo. The present study shows that effects of a single cup of tea may be limited to an immediate increase in pleasure and decrease in arousal, which can increase interest in activities. Differences between tea and water were not significant, while differences between water and placebo on implicit measures were unexpected. More servings over a longer time may be required to evoke tea's arousing effects and appropriate tea consumption settings may evoke more enduring valence effects.

Differential effects of hunger and satiety on insular cortex and hypothalamic functional connectivity.

The insula cortex and hypothalamus are implicated in eating behaviour, and contain receptor sites for peptides and hormones controlling energy balance. The insula encompasses multi-functional subregions, which display differential anatomical and functional connectivities with the rest of the brain. This study aimed to analyse the effect of fasting and satiation on the functional connectivity profiles of left and right anterior, middle, and posterior insula, and left and right hypothalamus. It was hypothesized that the profiles would be altered alongside changes in homeostatic energy balance. Nineteen healthy participants underwent two 7-min resting state functional magnetic resonance imaging scans, one when fasted and one when satiated. Functional connectivity between the left posterior insula and cerebellum/superior frontal gyrus, and between left hypothalamus and inferior frontal gyrus was stronger during fasting. Functional connectivity between the right middle insula and default mode structures (left and right posterior parietal cortex, cingulate cortex), and between right hypothalamus and superior parietal cortex was stronger during satiation. Differences in blood glucose levels between the scans accounted for several of the altered functional connectivities. The insula and hypothalamus appear to form a homeostatic energy balance network related to cognitive control of eating; prompting eating and preventing overeating when energy is depleted, and ending feeding or transferring attention away from food upon satiation. This study provides evidence of a lateralized dissociation of neural responses to energy modulations.

Children's suggestion-induced omission errors are not caused by memory erasure.

We explored whether children's suggestion-induced omission errors are caused by memory erasure. Seventy-five children were instructed to remove three pieces of clothing from a puppet. Next, they were confronted with evidence falsely suggesting that one of the items had not been removed. During two subsequent interviews separated by one week, children had to report which pieces of clothing they had removed. Children who during both interviews failed to report that they had removed the pertinent item (i.e., omission error; n=24) completed a choice reaction time task. In this task, they were presented with different clothing items. For each item, children had to indicate whether or not they had removed it. Significantly more errors were made for those removed items that children failed to report than for those they had not removed. This indicates that children's suggestion-based omission errors are not due to erasure of memories.

The corrective effects of warning on false memories in the DRM paradigm are limited to full attention conditions.

Effects of attention control and forewarning on the activation and monitoring of experimentally induced false memories in the Deese/Roediger-McDermott paradigm were investigated in a young adult sample (N=77). We found that reducing the degree of attention during encoding led to a decrease in veridical recall and an increase in non-presented critical lure intrusions. This effect could not be counteracted by a forewarning instruction. However, these findings did not emerge in a (retrieval supportive) recognition task. It seems that divided attention increases false recall when attention control and forewarning have to compete for limited cognitive resources in a generative free recall as opposed to a retrieval supportive recognition task. Forewarning instructions do not always protect young adults against experimentally induced false memories.

Acute dissociation predicts rapid habituation of skin conductance responses to aversive auditory probes.

The present study examined how acute dissociation, trait-like dissociative symptoms, and physiological reactivity relate to each other. Sixty-nine undergraduate students were exposed to 14 aversive auditory probes, while their skin conductance responses were measured. A combination of self-reported anxiety and trait-like dissociation was found to predict variability in peritraumatic dissociation levels induced by the aversive probes. Furthermore, high levels of acute dissociation were associated with faster habituation of skin conductance responding, while trait-like dissociation was unrelated to habituation. Interestingly, individuals who reported childhood trauma displayed elevated skin conductance responses. Our findings contribute to the growing body of evidence indicating that subjective feelings of acute dissociation have their objective concomitants, notably fast habituation of physiologic responses.

Trait dissociation and commission errors in memory reports of emotional events.

In 2 studies we examined whether trait dissociation is related to spontaneous commission errors (reports of events that did not occur) in free recall of emotional events. We also explored whether the functional locus of the dissociation-commission link is related to repeated retrieval or shallow encoding. In Experiment 1 participants were exposed to a staged incident and were repeatedly asked to add more information to their written accounts of the event. Dissociation levels were related to commission errors, indicating that people who report many dissociative experiences tend to make more commission errors. However, it was not the case that the overall increase in commission errors over successive retrieval attempts was typical for high dissociative participants. In Experiment 2 participants saw a video fragment of a severe car accident. During the video, half the participants performed a dual task, and the other half did not. Participants performing the dual task made more commission errors than controls, but this effect was not more pronounced in those with high trait dissociation scores. These studies show that there is a link between dissociation and spontaneous commission errors in memory reports of emotional events, but the functional locus of this link remains unclear.