title: Increasing generosity by disrupting prefrontal cortex.
abstract: Recent research suggests that prosocial outcomes in sharing games arise from prefrontal control of self-maximizing impulses. We used continuous theta burst stimulation (cTBS) to disrupt the functioning of two prefrontal areas, the right dorsolateral prefrontal cortex (DLPFC) and the dorsomedial prefrontal cortex (DMPFC). We used cTBS in the right MT/V5, as a control area. We then tested subjects' prosocial inclinations with an unsupervised Dictator Game in which they allocated real money anonymously between themselves and low and high socioeconomic status (SES) players. cTBS over the two prefrontal sites made subjects more generous compared to MT/V5. More specifically, cTBS over DLPFC increased offers to high-SES players, while cTBS over DMPFC caused increased offers to low-SES players. These data, the first to demonstrate an effect of disruptive neuromodulation on costly sharing, suggest that DLPFC and MPFC exert inhibitory control over prosocial inclinations during costly sharing, though they may do so in different ways. DLPFC may implement contextual control, while DMPFC may implement a tonic form of control. This study demonstrates that humans' prepotent inclination is toward prosocial outcomes when cognitive control is reduced, even when prosocial decisions carry no strategic benefit and concerns for reputation are minimized.
authors.affiliation: a Ahmanson-Lovelace Brain Mapping Center, Department of Psychiatry and Biobehavioral Sciences , David Geffen School of Medicine at UCLA , Los Angeles , CA , USA.
authors.forename: Leonardo
authors.initials: L
authors.lastname: Christov-Moore
authors.affiliation: b Division of Biokinesiology and Physical Therapy , Keck School of Medicine, University of Southern California , Los Angeles , CA , USA.
authors.forename: Taisei
authors.initials: T
authors.lastname: Sugiyama
authors.affiliation: c Cold Spring Harbor Laboratory, Watson School of Biological Sciences , Cold Spring Harbor , NY , USA.
authors.forename: Kristina
authors.initials: K
authors.lastname: Grigaityte
authors.affiliation: a Ahmanson-Lovelace Brain Mapping Center, Department of Psychiatry and Biobehavioral Sciences , David Geffen School of Medicine at UCLA , Los Angeles , CA , USA.
authors.forename: Marco
authors.initials: M
authors.lastname: Iacoboni
mesh_terms: D000293:Adolescent; D000328:Adult; D003071:Cognition / Q000502:physiology; D004645:Empathy / Q000502:physiology*; D056344:Executive Function / Q000502:physiology; D005260:Female; D005717:Games, Experimental; D006801:Humans; D007398:Interpersonal Relations; D008279:Magnetic Resonance Imaging; D008297:Male; D009483:Neuropsychological Tests; D017397:Prefrontal Cortex / Q000502:physiology*; D057566:Self Report; D012919:Social Behavior; D012959:Socioeconomic Factors; D013826:Theta Rhythm / Q000502:physiology; D050781:Transcranial Magnetic Stimulation; D055815:Young Adult
keywords: Empathy; cognitive control; neuroeconomics; prosocial behavior; transcranial magnetic stimulation