Coming from Professor Semir Zeki and John Romaya of the Wellcome Laboratory of Neurobiology at the University College London, a new research paper in Plos One on how hatred activates and deactivates areas of the brain shows hate creates a unique pattern of brain activates which includes some overlap with brain areas activated by love.
In this work, we address an important but unexplored topic, namely the neural correlates of hate. In a block-design fMRI study, we scanned 17 normal human subjects while they viewed the face of a person they hated and also faces of acquaintances for whom they had neutral feelings. A hate score was obtained for the object of hate for each subject and this was used as a covariate in a between-subject random effects analysis. Viewing a hated face resulted in increased activity in the medial frontal gyrus, right putamen, bilaterally in premotor cortex, in the frontal pole and bilaterally in the medial insula. We also found three areas where activation correlated linearly with the declared level of hatred, the right insula, right premotor cortex and the right fronto-medial gyrus. One area of deactivation was found in the right superior frontal gyrus. The study thus shows that there is a unique pattern of activity in the brain in the context of hate. Though distinct from the pattern of activity that correlates with romantic love, this pattern nevertheless shares two areas with the latter, namely the putamen and the insula.
Hatred does not activate the amygdala which is activated by fear.
It is important to note that the pattern revealed is distinct from that of other, closely related, emotions such as fear, anger, aggression and danger, even though it shares common areas with these other sentiments. Thus, the amygdala which is strongly activated by fear (Noesselt et al. 2005 , Morris et al. 2002 , Hadjikhani et al. 2008 ) and by aggression (Beaver et al., 2008 ) was not activated in our study. Nor were the anterior cingulate, hippocampus, medial temporal regions, and orbitofrontal cortex, apparently conspicuous in anger and threat (Denson et al. 2008 ; Bufkin and Luttrell 2007 ; McClure et al. 2004 ), evident in our study. It would thus seem that, though these sentiments may constitute part of the behaviour that results from hatred, the neural pathways for hate are distinct.
The 'hate circuit' includes structures in the cortex and in the sub-cortex and has components that are important in generating aggressive behaviour, and translating this into action through motor planning, as if the brain becomes mobilised to take some action. It also involves a part of the frontal cortex that has been considered critical in predicting the actions of others, probably an important feature when one is confronted by a hated person.
The subcortical activity involves two distinct structures, the putamen and insula. The former, which has been implicated in the perception of contempt and disgust, may also be part of the motor system that is mobilised to take action, since it is known to contain nerve cells that are active in phases preparatory to making a move.
Professor Zeki added: "Significantly, the putamen and insula are also both activated by romantic love. This is not surprising. The putamen could also be involved in the preparation of aggressive acts in a romantic context, as in situations when a rival presents a danger. Previous studies have suggested that the insula may be involved in responses to distressing stimuli, and the viewing of both a loved and a hated face may constitute such a distressing signal.
While love shuts down areas of the brain associated with judgment and reasoning by contrast those consumed with hate have very active reasoning facilities. It takes logic to figure out how to attack your enemy. So that makes sense. Only those in love think they can afford to let their guard down, become zombies, and feel bliss around the object of their affection.
"A marked difference in the cortical pattern produced by these two sentiments of love and hate is that, whereas with love large parts of the cerebral cortex associated with judgment and reasoning become de-activated, with hate only a small zone, located in the frontal cortex, becomes de-activated. 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.
In countries where suspected criminals have no right to privacy or right to keep silent brain scans could be used to determine whether a suspected killer hated his victim and by how much.
"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."
One could imagine a police state in which opponents of the regime get tested with brain scans and pictures of dictators to identify enemies of the state. With more time it will become possible for governments to turn hatred into love. Then all enemies of the state will get turned into supporters of it. Of course, individuals will try to do this on a smaller scale as well.
Contrast these results with the research into love. See my previous posts Love Deactivates Brain Areas For Fear, Planning, Critical Social Assessment, Love Like Addiction In Brain Scans, What Brain Scans Of People Falling In Love Tell Us, Romantic Love Seen As Motivation Or Drive Rather Than Emotional State, and Love Is Blind: Couples In Love Can't Identify Who Else Is In Love.
|Share |||Randall Parker, 2008 October 29 12:09 AM Brain Emotions|