Affective coldness is one of the main features of Machiavellianism. Recent studies have revealed that Machiavellians are emotionally detached and that this "affective blunting" is associated with intense feelings, emotional instability, negative emotions, and difficulty in enduring distress. We used brain-imaging techniques to investigate emotion regulation in Machiavellianism at a neuropsychological level. We used situations in which participants were required to demonstrate emotional flexibility to explore the controversy surrounding the fact that Machiavellianism is associated with both cold-mindedness and emotional instability. Participants performed a reappraisal task in which emotionally evocative pictures (from the International Affective Picture System) were presented in different contexts (negative, positive, and neutral). They were asked to interpret a scenario according to its title and to reinterpret it according to another context created by a new title (e.g., negatively labeled pictures shifted to positively labeled ones). During task performance, Machiavellians showed increased activation of brain regions associated with emotion generation-for example, the amygdala and insula. This indicates that Machiavellian individuals are able to be involved emotionally in social situations. Increased activation in the temporal and parahippocampal regions during reappraisal suggests that Machiavellians use semantic-perceptual processes to construct alternative interpretations of the same situation and have enhanced memory for emotional stimuli. Furthermore, they seem to possess an intense awareness that leads them to shift attention from external to internal information to detect environmental changes. These cognitive processes may enable them to adjust their behavior quickly. This study supports the flexibility hypothesis of Machiavellianism and suggests that Machiavellians' approach to emotion regulation is linked to their rational mode of thinking.

Emotional flexibility reflects the ability to adjust the emotional response to the changing environmental context. To understand how context can trigger a change in emotional response, i.e., how it can upregulate the initial emotional response or trigger a shift in the valence of emotional response, we used a task consisting of picture pairs during functional magnetic resonance imaging sessions. In each pair, the first picture was a smaller detail (a decontextualized photograph depicting emotions using primarily facial and postural expressions) from the second (contextualized) picture, and the neural response to a decontextualized picture was compared with the same picture in a context. Thirty-one healthy participants (18 females; mean age: 24.44 ± 3.4) were involved in the study. In general, context (vs. pictures without context) increased activation in areas involved in facial emotional processing (e.g., middle temporal gyrus, fusiform gyrus, and temporal pole) and affective mentalizing (e.g., precuneus, temporoparietal junction). After excluding the general effect of context by using an exclusive mask with activation to context vs. no-context, the automatic shift from positive to negative valence induced by the context was associated with increased activation in the thalamus, caudate, medial frontal gyrus and lateral orbitofrontal cortex. When the meaning changed from negative to positive, it resulted in a less widespread activation pattern, mainly in the precuneus, middle temporal gyrus, and occipital lobe. Providing context cues to facial information recruited brain areas that induced changes in the emotional responses and interpretation of the emotional situations automatically to support emotional flexibility.

Considering the mixed nature of reports of flexibility difficulties in autism, we hypothesized that a task that more closely resembles the challenges faced in real life would help to assess these difficulties. Autistic and typically developing (TD) adults performed an online Emotional Shifting Task (EST), involving non-explicit unpredictable shifts of complex socio-emotional stimuli, and the Task Switching Task (TST), involving explicit predictable shifts of simple character stimuli. Switch cost (i.e., the difference in performance between Shift and Non-Shift conditions) was larger in the autistic group than in the comparison group for the EST but not for the TST. Females responded faster than males in the EST. On the TST, TD males responded faster than TD females, whereas there was a female advantage in the autistic group. Our findings suggest that factors such as predictability, explicitness of the shift rule, stimulus type as well as sex could play a critical role in flexibility difficulties in autism.