Susceptibility to emotional contagion predicts the ability to discriminate faked from genuine smiles
Being able to detect feigned from real facial expressions such as genuine smiles from faked smiles is an integral part of social cognition and highly challenging task for the human brain. There are a number of instances where faked smiles can be produced, for example to hide information, and being able to recognize faked smiles can prevent one from being deceived or from acting inappropriately in social situations. It has been shown previously that there is substantial inter-individual variability in the ability to discriminate between felt and simulated happy expressions, but fairly little is known about the determinants that underlie this variability.
In their recent study, Manera et al. (2013) tested a hypothesis that the ability to discriminate between real and faked smiles is determined by the sensitivity of a person to emotional contagion. They tested the susceptibility of 108 healthy volunteers to emotional contagion by administering the so-called Emotional Contagion Scale. The subjects then underwent a validated smile recognition task consisting of 25 color pictures showing real and faked smiles, with variability in the facial muscles involved in the generation of the smiles. The subjects were to indicate after each picture whether they perceived the smiling person as really happy or just pretending to be happy.
The authors observed that susceptibility to emotional contagion indeed explained significant part of the individual variation in the ability to discriminate between real and faked smiles. Interestingly, the authors further observed that susceptibility to emotional contagion by negative emotions went hand in hand with increased ability to detect faked smiles, whereas susceptibility to emotional contagion by positive emotions predicted reduced ability to detect faked smiles, with faked smiles being perceived as positive ones. While these findings were limited to still pictures of single-gender facial expressions, they are nonetheless highly important and encouraging and pave way for further studies on factors governing the ability to perceive genuine from faked emotional expressions.
Reference: Manera V, Grandi E, Colle L. Susceptibility to emotional contagion for negative emotions improves detection of smile authenticity. Frontiers in Human Neuroscience (2013) 7:6. http://dx.doi.org/10.3389/fnhum.2013.00006
During the last few years, so-called decoding approaches have been providing novel information about the neural basis of cognitive functions at a rapidly increasing pace. The strength of such machine-learning algorithms is in that they make it possible to find distributed patterns of brain activity that are associated with specific mental states and cognitive processes. Decoding studies have, for example, disclosed specific distributed replicable “signature” patterns of brain activity that represent perceptual object categories such as chairs, tables, and butterflies within specific visual cortical areas. Studies attempting to decode higher-order cognitive processes such as inferring intentions of other persons represent in many ways the next major step forward in cognitive neuroscience.
In their recent study, Dr. Koster-Hale et al. (2013) conducted four functional magnetic resonance imaging experiments in healthy volunteers and in subjects with high-functioning autism-spectrum disorder to decode brain hemodynamic response patterns that underlie mental state reasoning, i.e., hold representations of others’ beliefs and intentions. In two of the studies, the healthy and autistic subjects were reading short stories of intended vs. non-intended harms vs. neutral stories in second person, and were to indicate with button presses after each story how much blame they ought to get from none to very much. In the other two studies, short stories describing intentional harms vs. accidental harms vs. harmless actions were read in third person, and the subjects were to either make moral judgments (from “forbidden” to “permissible”) or were to provide a true/false answer to a question concerning the stories.
The authors observed that difference between accidental and intentional harmful actions in the short stories was decodable from replicable and specific patterns of hemodynamic activity within the right temporo-parietal junction. These patterns further predicted on the invididual-participant level differences in moral judgments: individuals with more distinct activity patterns between intentional and accidental harm conditions in right temporo-parietal junction exhibited stronger moral judgment of intentional harms as contrast to accidental harms. As the third major finding, the authors report that these findings are absent in their group of subjects suffering from high-functioning type of autism spectrum disorder, and indeed individuals with this diagnosis are known to make moral judgments less on the basis of intent information than neurotypical control subjects. Together, these findings very nicely demonstrate the power of decoding approach in elucidating cerebral processing that supports higher-order cognitive processes such as mental-state inference, and show the pivotal role of right temporo-parietal junction in mental-state inference.
Reference: Koster-Hale J, Saxe R, Dungan J, Young LL. Decoding moral judgments from neural representations of intentions. Proc Natl Acad Sci USA (2013) e-publication ahead of print. http://dx.doi.org/10.1073/pnas.1207992110
Humor is a commonplace and integral part of one’s everyday life, including but not limited to social interactions. Cognitive models of humor processing have been proposed where there is first detection of incongruity followed by resolution that is, at the final step during the comprehension and elaboration of humor, found amusing. Neuroimaging studies have identified a number of brain structures activated during comprehension of humor, but the cerebral events specifically underlying incongruity detection and incongruity resolution have remained less well known.
In their recent study Chan et al. (2013) investigated the neural basis of humorous incongruity detection and resolution in 22 healthy volunteers who were presented with unfunny, non-humorous nonsensical, and funny stories during event-related functional magnetic resonance imaging. Specifically, the stories consisted of setup and punch line parts. The punch line was altered in the unfunny and non-humorous nonsensical stimuli so that the humorous resolution was removed. The unfunny stimuli provided a punch line that was congruent with the setup and the non-humorous nonsensical stimuli provided a punch line that was incongruent with the setup yet lacked the humorous resolution. Hemodynamic responses were then contrasted to elucidate brain structures associated with incongruence detection and resolution processes.
The authors observed that detection of incongruity was associated with stronger hemodynamic responses in the right middle temporal and middle frontal gyri, with ratings of surprisingness of the punch lines further predicting activity of the right middle temporal gyrus. Their results further indicated that semantic selection and integration associated with incongruity resolution involved inferior frontal gyri bilaterally as well as left superior frontal gyrus and inferior parietal lobule. Taken together, these results very nicely elucidate the differential cerebral events that underlie detection and resolution of incongruity during humor comprehension.
Reference: Chan YC, Chou TL, Chen HC, Yeh YC, Lavallee JP, Liang KC, Chang KE. Towards a neural circuit model of verbal humor processing: an fMRI study of the neural substrates of incongruity detection and resolution. Neuroimage (2013) 66: 169–176. http://dx.doi.org/10.1016/j.neuroimage.2012.10.019
Atypical functional network activity of default mode network and auditory cortices predispose to auditory hallucinations
Auditory hallucinations, hearing voices without external stimulation, constitute one of the most frequent symptoms in debilitating psychotic disorders such as schizophrenia. While in psychotic disorders auditory hallucinations are associated with other symptoms such as delusional thinking and emotional disturbances, and typically their hallucinations are of psychologically disturbing and threatening nature (e.g., voices commanding the patient to commit suicide), there are also healthy persons who have benign auditory hallucinations. Given that auditory hallucinations in healthy subjects are present as an isolated symptom, such individuals offer a very interesting possibility to study the neural basis of auditory hallucinations as an isolated phenomenon.
In their recent study, Lutterveld et al. (2013) obtained resting-state (i.e., without any sensory stimuli or tasks) functional magnetic resonance imaging data in healthy subjects with auditory hallucinations and in control subjects who do not experience auditory hallucinations. The authors specifically scanned the subjects when they were not experiencing hallucinations to exclude hallucination-related transient hemodynamic responses. Functional connectivity patterns (i.e., brain networks) of these two subject groups were then compared with complex network analysis methods.
The authors observed that temporal (auditory) cortical areas and posterior-parietal cortex constituted stronger functional “hub” regions in subjects with auditory hallucinations, as compared with the control subjects. Given that the posterior parietal cortex is an essential part of the so-called “default-mode network” hypothesized to be involved in, e.g., self-referential thinking, these highly exciting results suggest that atypical functioning of the default mode network and auditory cortices underlie predisposition to auditory hallucinations.
Reference: van Lutterveld R, Diederen KMJ, Otte WM, Sommer IE. Network analysis of auditory hallucinations in nonpsychotic individuals. Human Brain Mapping (2013), e-publication ahead of print. http://dx.doi.org/10.1002/hbm.22264