No abstract

SummaryData analysis workflows in many scientific domains have become increasingly complex and flexible. To assess the impact of this flexibility on functional magnetic resonance imaging (fMRI) results, the same dataset was independently analyzed by 70 teams, testing nine ex-ante hypotheses. The flexibility of analytic approaches is exemplified by the fact that no two teams chose identical workflows to analyze the data. This flexibility resulted in sizeable variation in hypothesis test results, even for teams whose statistical maps were highly correlated at intermediate stages of their analysis pipeline. Variation in reported results was related to several aspects of analysis methodology. Importantly, meta-analytic approaches that aggregated information across teams yielded significant consensus in activated regions across teams. Furthermore, prediction markets of researchers in the field revealed an overestimation of the likelihood of significant findings, even by researchers with direct knowledge of the dataset. Our findings show that analytic flexibility can have substantial effects on scientific conclusions, and demonstrate factors related to variability in fMRI. The results emphasize the importance of validating and sharing complex analysis workflows, and demonstrate the need for multiple analyses of the same data. Potential approaches to mitigate issues related to analytical variability are discussed.

Power dynamics are a ubiquitous feature of human social life, yet little is known about how power is implemented in the brain. Motor resonance is the activation of similar brain networks when acting and when watching someone else act, and is thought to be implemented, in part, by the human mirror system. We investigated the effects of power on motor resonance during an action observation task. Separate groups of participants underwent a high-, neutral, or low-power induction priming procedure, prior to observing the actions of another person. During observation, motor resonance was determined with transcranial magnetic stimulation (TMS) via measures of motor cortical output. High-power participants demonstrated lower levels of resonance than low-power participants, suggesting reduced mirroring of other people in those with power. These differences suggest that decreased motor resonance to others' actions might be one of the neural mechanisms underlying power-induced asymmetries in processing our social interaction partners.

The control of neurological networks supporting social cognition is crucially important for social interaction. In particular, the control of imitation is directly linked to interaction quality, with impairments associated with disorders characterized by social difficulties. Previous work suggests inferior frontal cortex (IFC) and the temporoparietal junction (TPJ) are involved in controlling imitation, but the functional roles of these areas remain unclear. Here, transcranial direct current stimulation (tDCS) was used to enhance cortical excitability at IFC and the TPJ prior to the completion of three tasks: (i) a naturalistic social interaction during which increased imitation is known to improve rapport, (ii) a choice reaction time task in which imitation needs to be inhibited for successful performance and (iii) a non-imitative control task. Relative to sham stimulation, stimulating IFC improved the context-dependent control of imitation—participants imitated more during the social interaction and less during the imitation inhibition task. In contrast, stimulating the TPJ reduced imitation in the inhibition task without affecting imitation during social interaction. Neither stimulation site affected the non-imitative control task. These data support a model in which IFC modulates imitation directly according to task demands, whereas TPJ controls task-appropriate shifts in attention toward representation of the self or the other, indirectly impacting upon imitation.

Results support the use of both HD- and conventional tDCS to the IFC for improving response inhibition, providing empirical evidence that HD-tDCS can be used to facilitate performance on an executive function task.

Alexithymia is a subclinical condition characterized by impaired awareness of one’s emotional states, which has profound effects on mental health and social interaction. Despite the clinical significance of this condition, the neurocognitive impairment(s) that lead to alexithymia remain unclear. Recent theoretical models suggest that impaired anterior insula (AI) functioning might be involved in alexithymia, but conclusive evidence for this hypothesis is lacking. We measured alexithymia levels in a large sample of brain-injured patients (N=129) and non-brain-injured control participants (N=33), to determine whether alexithymia can be acquired after pronounced damage to the AI. Alexithymia levels were first analyzed as a function of group, with patients separated into four groups based on AI damage: patients with >15% damage to AI, patients with <15% damage to AI, patients with no damage to AI, and healthy controls. An ANOVA revealed that alexithymia levels varied across groups (p=0.009), with >15% AI damage causing higher alexithymia relative to all other groups (all p<0.01). Next, a multiple linear regression model was fit with the degree of damage to AI, the degree of damage to a related region (the anterior cingulate cortex, ACC), and the degree of damage to the whole brain as predictor variables, and alexithymia as the dependent variable. Critically, increased AI damage predicted increased alexithymia after controlling for the other two regressors (ACC damage; total lesion volume). Collectively, our results suggest that pronounced AI damage causes increased levels of alexithymia, providing critical evidence that this region supports emotional awareness.

‘Emotional intelligence’ (EI) is one of the most highly used psychological terms in popular nomenclature, yet its construct, divergent, and predictive validities are contentiously debated. Despite this debate, the EI construct is composed of a set of emotional abilities – recognizing emotional states in the self and others, using emotions to guide thought and behavior, understanding how emotions shape behavior, and emotion regulation – that undoubtedly influence important social and personal outcomes. In this review, evidence from human lesion studies is reviewed in order to provide insight into the necessary brain regions for each of these core emotional abilities. Critically, we consider how this neuropsychological evidence might help to guide efforts to define and measure EI.

Imitation is a fundamentally important human capability and has been the topic of considerable research in the behavioural sciences. One paradigm for investigating the basic nature of imitation is the "automatic imitation" paradigm. In this paradigm, participants are symbolically cued to make a particular response, whilst being incidentally exposed to a congruent or incongruent motor action performed by another person. The robust finding is that when the incidental action is incongruent with the cued action, participants are slower to respond than when it is congruent. Despite the name given to this paradigm, the extent to which the imitative tendency involved is actually automatic remains unclear. Here, we manipulated the probability of congruent and incongruent trials within blocks to assess the effects of expectation on the imitative process. In addition, we determined whether an individual difference variable related to how people process others' behaviour-narcissism-affected the automaticity of imitation. Our results confirm that imitation as observed in this paradigm is robust in the face of expectation. However, the degree to which expectation modulates automatic imitation was enhanced for individuals who scored higher on a narcissism inventory. Together, these results suggest that imitation in the automatic imitation paradigm is indeed largely automatic, but that individual differences in narcissism can change the extent to which imitative behaviour manifests.