UK: Scientists identify brain's "hate circuit"

Show an individual a picture of someone they hate and it will stimulate parts of their brain associated with aggressive behaviour, planning physical action and predicting other people's actions, research by University College London academics shows.

The scientists, Professor Semir Zeki and John Romaya of the Wellcome Laboratory of Neurobiology at UCL, have dubbed the activity the "hate circuit" and published their work in PLoS One. Zeki and Romaya scanned the brains of 17 subjects, female and male, while showing them pictures of a person they hated as well as those of neutral faces with which they were familiar.

Viewing a hated person resulted in activity in distinct areas of the brain, including structures in the cortex and in the sub-cortex. The study followed similar research from the Wellcome Laboratory, which examined the brain mechanisms of romantic and maternal love.

"Hate is often considered to be an evil passion that should, in a better world, be tamed, controlled, and eradicated," Zeki said. "Yet to the biologist, hate is a passion that is of equal interest to love. Like love, it is often seemingly irrational and can lead individuals to heroic and evil deeds. How can two opposite sentiments lead to the same behaviour?"

Zeki said some parts of the hate circuit were also activated by romantic love. A marked difference in the cortical pattern produced by the two sentiments of love and hate was that, whereas with love large parts of the cerebral cortex associated with judgment and reasoning became deactivated, with hate only a small zone located in the frontal cortex was deactivated.

"This may seem surprising since hate can also be an all-consuming passion, just like love. But whereas in romantic love, the lover is often less critical and judgmental regarding the loved person, it is more likely that in the context of hate the hater may want to exercise judgment in calculating moves to harm, injure or otherwise extract revenge.

"Interestingly, the activity in some of these structures in response to viewing a hated face is proportional in strength to the declared intensity of hate, thus allowing the subjective state of hate to be objectively quantified. This finding may have legal implications in criminal cases, for example."

Unlike romantic love, which is directed at one person, hate can be directed against entire individuals or groups, as is the case with racial, political, or gender hatred. Zeki said these different varieties of hate would be the subject of future studies from his laboratory.

john.gerritsen@uw-news.com