You can now read 10 articles in a month for free on BostonGlobe.com. Read as much as you want anywhere and anytime for just 99¢.

The Boston Globe

Books

Book review

‘Moral Tribes’ by Joshua Greene

You’re alone in a rail yard when suddenly you spot a runaway trolley. Looking around for help, you notice five workers all tied up on the track in the careening car’s path. There is a lever nearby. Pull it, and the trolley will divert to a sidetrack saving the five. But there is a man on the sidetrack who will be hit and killed. What do you do?

Joshua Greene revolutionized the study of morality by scanning the brains of individuals while they puzzled over philosophical questions such as this one. From this research, Greene made stunning discoveries about how individuals contemplate issues of right and wrong and how different neural networks respond differently depending on the degree of personal involvement in a dilemma.

Loading comments...

You have reached the limit of 10 free articles in a month

Stay informed with unlimited access to Boston’s trusted news source.

  • High-quality journalism from the region’s largest newsroom
  • Convenient access across all of your devices
  • Today’s Headlines daily newsletter
  • Subscriber-only access to exclusive offers, events, contests, eBooks, and more
  • Less than 25¢ a week