What is are emotion around Equality and Diversity

The proverbs tell us that there's a fine line between love and hate, and new scans of the brain's "hate circuit" have confirmed similarities between the two powerful emotions.

But whereas loved-up partners are likely to be less rational, the new scans show hate to be colder and more calculating.

Semir Zeki of University College London, UK, who has previously mapped the neural circuits involved in romantic and maternal love, and colleague John Romaya selected 17 subjects who expressed a strong hatred for an individual - typically an ex-lover or colleague.

The subjects answered a questionnaire to assess the level of their hatred, and they provided the team with a photo of their nemesis, along with pictures of three other less provocative individuals.

Each subject then viewed their chosen photos for roughly 16 seconds, while an MRI scanner mapped the activity in their brain. By comparing their responses to the hated face with their reaction to the neutral photos, the team could identify the neurological circuits we use when feeling intense hatred.

The results showed two brain regions that our "hate circuit" shares with the "love circuit" - the putamen and the insular cortex or insula.

The putamen is thought to be used to prepare the body for movement - so it's possible this be active either to provide protection of the loved one, or to prepare for an aggressive or spiteful act from the hated one. The insula is associated with feelings of distress, such as jealousy.

Scheming hatred

However, there was also an important difference. The areas of the frontal cortex associated with judgement and reasoning are typically less active when viewing a lover compared to someone more neutral, meaning they are less likely to feel critical of their partner.

The hate-filled subjects, though, only showed a reduction in one small part of this area, while the rest was still active.

We may use this area to judge the consequences of our actions and to predict the behaviour of our nemesis, Zeki says. "In love, you take leave of your senses and go wild for that person, but in hatred it seems you must be all there to calculate your next move," he says.

The team found that the amount of brain activity corresponded with the level of hatred the subjects had previously admitted in the questionnaire.

Zeki suggests similar brain scans could one day be used in court - for example, to assess whether a murder suspect felt a lot of hatred towards the victim.

In the future, he hopes to investigate how brain activity would differ when experiencing hatred towards a group of people rather than a specific individual - for example, a race or nationality, sexual orientation, disability, trangender, age, religious belief, social class.

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