A new split-brain study reveals a clearer picture about the areas of the brain that play a role in complex reasoning, such as moral judgment. Historically, studying split-brain patients—those whose corpus callosum has been severed, effectively reducing communication between right and left hemispheres of the brain—has allowed researchers to gain greater insight into specific areas of the brain responsible for certain mental processes. The present study tested whether the right hemisphere alone is enough to generate so-called intent-based moral judgement –  i.e., evaluating moral actions in fictional scenarios based on intentions versus outcomes. Previous research suggested that the right hemisphere plays a big role in focusing on moral intentions; when tested in left hemisphere alone, split-brain patients evaluated actions based on outcomes only, not intent. The present study supports this finding; moreover, researchers say that the right brain alone is enough to make intent-based moral judgments.


Conor M. Steckler, J. Kiley Hamlin, Michael B. Miller, Danielle King, Alan Kingstone

Corresponding author:

Conor Steckler, Department of Psychology, University of British Columbia, Email: conor.steckler@psych.ubc.ca

Original paper published in Royal Society Open Science on July 26, 2017.