Generalized social anxiety disorder is a highly prevalent and disabling psychiatric illness that is characterized by excessive fear of public scrutiny and negative evaluation across a variety of social situations [1
]. The underlying cause of this exaggerated social fear is unknown, but could partly be because of deficits in social cognition, which manifest as a tendency toward inaccurate and distorted interpretations of the beliefs and intentions of others during interpersonal interactions [3
]. Identification of a neural mechanism that explains these social-cognitive deficits in generalized social anxiety disorder (hereafter referred to as ‘social anxiety’) remains elusive.
So far, evidence for brain-based dysfunction in social anxiety has focused on exaggerated reactivity of the amygdala in response to facial signals that convey criticism and/or negative feedback (angry, contemptuous/disgusted, and/or fearful faces) (for meta-analysis, see Ref. [4
]). However, the usefulness of static face stimuli in elucidating social-cognitive deficits in social anxiety is likely to be limited, as these stimuli primarily engage perception of emotional signals, typically do not engage prefrontal cortex, and do not reflect real-world social interactions that are inherently dynamic and interactive.
Functional magnetic resonance imaging (fMRI) studies of social cognition have recently used a novel approach called ‘social neuroeconomics’ [5
], which uses economic game theory to dynamically model fundamental aspects of social interaction such as cooperation, trust, and social signaling [7
]. Collectively, these studies have begun to characterize the neural correlates of social interactions, including processes that encode the motives and intentions of social partners to guide appropriate behaviors, referred to as ‘theory of mind’ or ‘mentalizing’ [12
]. The medial prefrontal cortex has been implicated as a key brain region that implements mentalizing during the social interactions by these studies [12
], including those studies that have specifically used economic exchange games [7
As a prototypical interactive economic exchange game, the ‘trust game’ serves as a potent probe of mentalizing abilities because it sets up the need to make inferences about the mental state of others [7
], including partners’ beliefs, desires, intentions, and certain dispositions (e.g. trustworthiness, reliability, approachability, etc.). Such information is crucial for predicting partners’ responses; as recently noted by Frith and Frith [14
], ‘It is important for us to be able to read the minds of others because it is their mental states that determine their actions’. Therefore, functional neuroimaging of the trust game [17
] may shed light on a novel behavioral and neural mechanism that explains the tendency of individuals with social anxiety to misinterpret partner motives, which may contribute to their reticence to enter into or continue social interactions. In this study, we used a version of the trust game previously coupled with fMRI [7
] to probe the neural correlates of mentalizing in social anxiety. Given that individuals with social anxiety tend to form inaccurate impressions about others [18
], we predicted that relative to healthy controls, prefrontal areas such as the medial prefrontal cortex would exhibit less engagement during mentalizing in individuals with social anxiety.