The Prefrontal Cortex and Moral Behavior

November 11, 1999

On September 13, 1848, railroad worker Phineas Gage was involved in an accident that drove a three-foot long iron bar through his skull. Although Mr. Gage survived, his behavior changed drastically. He went from being a hard-working, well-liked laborer to a gruff, rude, foul-mouthed drifter. Examination of Mr. Gage's skull has revealed that he suffered damage to the frontal lobes of his brain. The primary area of injury was to a part of the prefrontal cortex called the orbitofrontal cortex.

The skull of Phineas Gage.
Image courtesy of the National Library of Medicine, History of Medicine Collection


Approximate location of the
prefrontal cortex
Over 150 years later, there is more evidence that the prefrontal cortex may be important for moral behavior. Adults who suffer damage to the prefrontal cortex develop problems with making decisions and with behaving appropriately in social situations. Scientists at the University of Iowa have published a report (Nature Neuroscience, November 1999) about two adults who suffered prefrontal cortex damage when they were very young children. These two individuals had severe behavioral problems including impaired decision-making ability and "defective social and moral reasoning."

The Subjects

Subject A - Female, 20 yrs old

Behavior

  • She was run over by a vehicle when she was 15 months old.
  • At 3 years old, she did not respond to verbal or physical punishment.
  • At 14 years old, she was placed in a treatment facility.
  • Her intelligence appeared normal, but she did not complete her school work.
  • She often stole, did not tell the truth, and did not have any friends.
  • She was arrested many times.
  • She could not hold a job.
  • She never showed any remorse for her behavior and had no guilt.
Subject B - Male, 23 yrs old

Behavior

  • A tumor located in his right frontal lobe was removed when he was 3 months old.
  • At 9 years old, he had no motivation and usually showed few emotions. However, he had occasional explosions of anger.
  • He had poor work and grooming habits.
  • He could not hold a job
  • He had few friends.
  • He ate strange foods such as uncooked frozen dinners.
  • He often lied.
  • He got into fights and stole.
  • He showed no guilt or remorse for his behavior.
The brains of both subjects showed damage to the prefrontal cortex only. Subject A had brain damage on both sides of the brain; Subject B had damage on only the right side.

The scientists found that these two people had normal intelligence based on memory tests, language skills, math and problem-solving ability. However, they had problems with learning the rules and strategies of tests. For example, if they were given different rewards for selecting cards from four different decks of cards, they could not learn which deck of cards gave them the best reward.

The researchers also asked the subjects about real-life situations involving dilemmas and conflicts. For example, the subjects were asked what would be the right thing to do if a man had to steal a drug to save his wife's life. The subjects were also asked about what they would do if two people disagreed on which TV show to watch. Both subjects failed to come up with solutions to these problems and could not even identify the problems in the situations. The scientists estimated that the subjects had the moral reasoning of 10-year-old children.

Because there were only two subjects in this study, it is difficult to say with certainty that all people with damage to the prefrontal cortex will experience problems with moral behavior. Also, it is possible that people WITHOUT any apparent damage to the prefrontal cortex may also show these "psychopathic" behaviors. Nevertheless, this study suggests that the prefrontal cortex does play a role in the development and maintenance of moral behavior.

References and further information:

  1. Anderson, S.W., Bechara, A., Damasio, H., Tranel, D. and Damasio, A.R., Impairment of social and moral behavior related to early damage in human prefrontal cortex, Nature Neuroscience, 2:1032-1037, 1999.
  2. Lobes of the brain
  3. The Phineas Gage Information Page

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