Certain areas of the brain activate feelings of jealousy. Brain injury and stroke studies have revealed that jealousy is indeed "in your head”—specifically in the left part of the cerebral cortex. Activation or inhibition of certain regions of the brain can induce jealousy, although measures of decreased jealousy have not been recorded.
The jealous part of the brain
The cortical region of frontal lobe of the brain modulates decision-making abilities and self-control. Kelley and colleagues1 used transcranial direct-current stimulation to target the left or right frontal cortex on two groups of healthy volunteers for a period of 15 minutes. Both groups were instructed to play a game designed to provoke feelings of rejection and then answered questions by the researchers.
It turned out that the volunteers who received stimulation to the left frontal cortex reported greater feelings of jealousy after their experience of rejection than the volunteers who received the stimulus to the right frontal cortex who were exposed to the same experience of rejection.
1. Kelley NJ, Eastwick PW, Harmon-Jones E, Schmeichel BJ. Jealousy increased by induced relative left frontal cortical activity. Emotion. 2015;15:550-555.
2. Luauté JP, Saladini O, Luauté J. Neuroimaging correlates of chronic delusional jealousy after right cerebral infarction. J Neuropsychiatry Clin Neurosci. 2008;20:245-247.
3. Rocha S, Pinho J, Ferreira C, Machado Á. Othello syndrome after cerebrovascular infarction. J Neuropsychiatry Clin Neurosci. 2014;26:E1-E2.