Psychopathy is a personality disorder characterized by ‘a lack of empathy and remorse, shallow affect, glibness, manipulation and callousness.’ When individuals with psychopathy imagine others in pain, researchers have found that brain areas necessary for feeling empathy and concern for others fail to become active and connected to other important regions involved in affective processing and compassionate decision-making.

When you are in an agreeable and comfortable situation it is more difficult to empathize with another person’s suffering. At a neurobiological level – without a properly functioning supramarginal gyrus – your brain has a tough time putting itself in someone else’s shoes.

The right supramarginal gyrus ensures that we can decouple our perception of ourselves from that of others. When the neurons in this part of the brain were disrupted in the course of a research task, the participants found it difficult to stop from projecting their own feelings and circumstances onto others. The participants' assessments were also less accurate when they were forced to make particularly quick decisions.

In a study published in the Journal of Neuroscience on October 9, 2013, Max Planck researchers identified that the tendency to be egocentric is innate for human beings – but that a part of your brain recognizes a lack of empathy and autocorrects. This specific part of your brain is called the the right supramarginal gyrus. When this brain region doesn't function properly—or when we have to make particularly quick decisions—the researchers found one’s ability for empathy is dramatically reduced. This area of the brain helps us to distinguish our own emotional state from that of other people and is responsible for empathy and compassion.

Social support is not the same as merely being in the presence of others. The critical issue is reciprocity: being truly heard and seen by the people around us, feeling that we are held in someone else’s mind and heart. For our physiology to calm down, heal, and grow we need a visceral feeling of safety. No doctor can write a prescription for friendship and love: These are complex and hard-earned capacities. You don’t need a history of trauma to feel self-conscious and even panicked at a party with strangers — but trauma can turn the whole world into a gathering of aliens.

In trauma survivors, Van der Kolk notes, the parts of the brain that have evolved to monitor for danger remain overactivated and even the slightest sign of danger, real or misperceived, can trigger an acute stress response accompanied by intense unpleasant emotions and overwhelming sensations. Such posttraumatic reactions make it difficult for survivors to connect with other people, since closeness often triggers the sense of danger. And yet the very thing we come to most dread after experiencing trauma — close contact with other people — is also the thing we most need in order to regain psychoemotional solidity and begin healing.

This, he points out, is why we’ve evolved a refined mechanism for detecting danger — we’re incredibly attuned to even the subtlest emotional shifts in those around us and, even if we don’t always heed these intuitive readings, we can read another person’s friendliness or hostility on the basis of such imperceptible cues as brow tension, lip curvature, and body angles.

“The eye speaks to the brain in a language already highly organized and interpreted,” they reported in the now-seminal paper “What the Frog’s Eye Tells the Frog’s Brain,” published in 1959.

Which got McCulloch thinking about neurons. He knew that each of the brain’s nerve cells only fires after a minimum threshold has been reached: Enough of its neighboring nerve cells must send signals across the neuron’s synapses before it will fire off its own electrical spike. It occurred to McCulloch that this set-up was binary—either the neuron fires or it doesn’t. A neuron’s signal, he realized, is a proposition, and neurons seemed to work like logic gates, taking in multiple inputs and producing a single output. By varying a neuron’s firing threshold, it could be made to perform “and,” “or,” and “not” functions.

McCulloch and Pitts wrote up their findings in a now-seminal paper, “A Logical Calculus of Ideas Immanent in Nervous Activity,” published in the Bulletin of Mathematical Biophysics.