The neural basis of the bystander effect - The influence of group size on neural activity when witnessing an emergency

R. Hortensius, B. de Gelder

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Naturalistic observation and experimental studies in humans and other primates show that observing an individual in need automatically triggers helping behavior. The aim of the present study was to clarify the neurofunctional basis of social influences on individual helping behavior. We investigate whether when participants witness an emergency, while performing an unrelated color-naming task in an fMRI scanner, the number of bystanders present at the emergency influences neural activity in regions related to automatic action preparation. The results show a decrease in activity with the increase in group size in the left pre- and postcentral gyrus and left medial frontal gyrus. In contrast, regions related to visual perception and attention show an increase in activity. These results demonstrate the neural mechanisms of social influence on automatic action preparation that is at the core of helping behavior when witnessing an emergency.
Original languageEnglish
Pages (from-to)53-58
Number of pages6
JournalNeuroimage
Volume93
Issue number1
Early online date27 Feb 2014
DOIs
Publication statusPublished - Jun 2014

Keywords

  • Bystander effect
  • Action
  • Helping
  • Social interaction
  • fMRI
  • TRANSCRANIAL MAGNETIC STIMULATION
  • MEDIAL PREFRONTAL CORTEX
  • BRAIN-REGIONS
  • MOTOR
  • EMOTION
  • EMPATHY
  • FMRI
  • INTERVENTION
  • EXCITABILITY
  • PERSPECTIVE

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