Automatic brain response to facial emotion as a function of implicitly and explicitly measured extraversion

Area of Science:

• Neuroscience
• Psychology
• Personality Science

Background:

• Extraversion/introversion is a key personality trait influencing social behavior and sensory sensitivity.
• Traditional neuroimaging studies relied solely on self-report measures for personality assessment.
• Implicit personality measures offer insights into the implicit self-concept, complementing explicit self-report methods.

Purpose of the Study:

• To investigate automatic brain reactivity to facial emotions using functional magnetic resonance imaging (fMRI).
• To examine the relationship between implicitly and explicitly measured extraversion and neural responses to emotional faces.
• To explore the neurobiological underpinnings of social interaction preferences related to extraversion.

Main Methods:

• fMRI was employed to measure brain activity in 30 healthy women.
• Participants viewed briefly presented masked sad, happy, and neutral faces.
• Extraversion was assessed using the Implicit Association Test (IAT) and the NEO Five-Factor Inventory (NEO-FFI).

Main Results:

• Implicit extraversion (IAT) correlated negatively with reactivity in the caudate head, thalamus, and inferior frontal cortex to sad faces.
• Explicit extraversion (NEO-FFI) correlated negatively with reactivity in the inferior frontal cortex and putamen to sad faces.
• Both implicit and explicit extraversion measures showed inverse correlations with brain responses to happy faces in specific regions, including the caudate head and thalamus.

Conclusions:

• Heightened responsivity of the fronto-striatal-thalamic circuit to arousing facial emotions may underlie introverts' preference for avoiding social interactions.
• Integrating implicit and explicit measures is crucial for a comprehensive understanding of the neurobiology of extraversion, especially when investigating automatic neural responses.
• This study highlights the importance of implicit personality assessment in neuroimaging research on extraversion and social behavior.