It is well-known that social influences affect consumption decisions. We used functional magnetic resonance imaging (fMRI) to elucidate the neural mechanisms associated with social influence with regard to a common consumer good: music. Our study population was adolescents, age 12-17. Music is a common purchase in this age group, and it is widely believed that adolescent behavior is influenced by perceptions of popularity in their reference group. Using 15-second clips of songs from MySpace.com, we obtained behavioral measures of preferences and neurobiological responses to the songs. The data were gathered with, and without, the overall popularity of the song revealed. Song popularity had a significant effect on the participants' likability ratings of the songs. fMRI results showed a strong correlation between the participants' rating and activity in the caudate nucleus, a region previously implicated in reward-driven actions. The tendency to change one's evaluation of a song was positively correlated with activation in the anterior insula and anterior cingulate, two regions that are associated with physiological arousal and negative affective states. Sensitivity to popularity was linked to lower activation levels in the middle temporal gyrus, suggesting a lower depth of musical semantic processing. Our results suggest that a principal mechanism whereby popularity ratings affect consumer choice is through the anxiety generated by the mismatch between one's own preferences and others'. This mismatch anxiety motivates people to switch their choices in the direction of the consensus. Our data suggest that this is a major force behind the conformity observed in music tastes in some teenagers.

We use neuroimaging to predict cultural popularity -something that is popular in the broadest sense and appeals to a large number of individuals. Neuroeconomic research suggests that activity in reward-related regions of the brain, notably the orbitofrontal cortex and ventral striatum, is predictive of future purchasing decisions, but it is unknown whether the neural signals of a small group of individuals are predictive of the purchasing decisions of the population at large. For neuroimaging to be useful as a measure of widespread popularity, these neural responses would have to generalize to a much larger population that is not the direct subject of the brain imaging itself. Here, we test the possibility of using functional magnetic resonance imaging (fMRI) to predict the relative popularity of a common good: music. We used fMRI to measure the brain responses of a relatively small group of adolescents while listening to songs of largely unknown artists. As a measure of popularity, the sales of these songs were totaled for the three years following scanning, and brain responses were then correlated with these "future" earnings. Although subjective likability of the songs was not predictive of sales, activity within the ventral striatum was significantly correlated with the number of units sold. These results suggest that the neural responses to goods are not only predictive of purchase decisions for those individuals actually scanned, but such responses generalize to the population at large and may be used to predict cultural popularity.

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Objectives-The development and validation of the Center for Neurologic StudyLability Scale (CNS-LS), the first self report measure of aVective lability in patients with amyotrophic lateral sclerosis (ALS). Methods-Potential questionnaire items were identified through interviews with patients and families and expert review. Potential items, as well as measures of aVect intensity, aVective lability in psychopathology, and depression were administered to 99 patients with ALS for item selection and the examination of factor structure and construct validity. Testretest reliability was examined using an additional sample of 31 patients with ALS, and criterion related validity was examined by comparing CNS-LS scores with physicians' diagnoses of aVective lability in a sample of 77 patients with ALS. Results-A seven item questionnaire emerged, composed of two subscales measuring labile laughter (four items) and labile tearfulness (three items). The CNS-LS showed a pattern of associations with aVect intensity, aVective lability in psychopathology, and depression consistent with a scale measuring aVective lability. The CNS-LS also showed good testretest reliability and internal consistency, and successfully predicted physicians' diagnoses of aVective lability. An auxiliary subscale measuring labile frustration, anger, and impatience also emerged. Conclusions-The CNS-LS is a short, easily administered, and psychometrically sound measure of aVective lability for use with patients with ALS. It has potential applications as both a clinical screening device and a research tool. The need for future research into the relation of depression as well as labile frustration, anger, and impatience to the syndrome of aVective lability in neurological disorders is discussed.

BackgroundMyelination of white matter in the brain continues throughout adolescence and early adulthood. This cortical immaturity has been suggested as a potential cause of dangerous and impulsive behaviors in adolescence.Methodology/Principal FindingsWe tested this hypothesis in a group of healthy adolescents, age 12–18 (N = 91), who underwent diffusion tensor imaging (DTI) to delineate cortical white matter tracts. As a measure of real-world risk taking, participants completed the Adolescent Risk Questionnaire (ARQ) which measures engagement in dangerous activities. After adjusting for age-related changes in both DTI and ARQ, engagement in dangerous behaviors was found to be positively correlated with fractional anisotropy and negatively correlated with transverse diffusivity in frontal white matter tracts, indicative of increased myelination and/or density of fibers (ages 14–18, N = 60).Conclusions/SignificanceThe direction of correlation suggests that rather than having immature cortices, adolescents who engage in dangerous activities have frontal white matter tracts that are more adult in form than their more conservative peers.