Robert Sapolsky on Our Metaphorical Brains

Robert Sapolsky, a Stanford professor, studies primates and what makes us human.  In an online commentary from the New York Times, Sapolsky explains how our brain differs from other animals.  The structure of our brains grow out of the same building blocks as everything else.  The neurons of all animals follow the same structure and work the same way.  Our main advantage is shear numbers.  


We have 100 billion neurons which create a seemingly infinite number of synapses and pathways.  Some scientists hope to build a connectome to show how each neuron communicates with another.  We have almost finished the complex connectome of model nematode, C. elegans.  The human connectome shows several orders of magnitude more complexity and is years away.  But even without visualizing every connection in the brain, we can understand the importance of these synapses to human capabilities.  Sapolsky notes our unique language center (Broca's Area), fine motor area, and neuron-dense frontal cortex.  Specifically, our frontal cortex controls emotional reactions, personalities, decision-making, and planning abilities.



However, Sapolsky points to our use of metaphors and symbols to describe reality.  He describes a person eating rotten food.  That person's neurons in their insula will remember the disgusting food and the need to vomit.  The same neurons will fire when a person smells the same food or think about eating similarly disgusting food.  Interestingly, those neurons will fire when we hear a story which "makes us sick" or react to something that it morally disgusting.  We didn't invent anything new, but built upon the existing model.  


We see the same situation in pain response.  Neurons fire when our body senses pain, but the same neurons fire when the see someone else in pain.  We feel their pain, sometimes almost literally.  The effects of clinical depression disappear when medicines block the actions of neurotransmitters associated with pain.  Perhaps depression manifests because of extreme empathy.


In many ways, our brains confuse the literal and the metaphorical reality.  The same neuronal circuitry fire in each case - disgust, pain, cleanliness, temperature, or touch.  Because evolution doesn't have to make new structures, our language symbols latched onto the neural networks already associated to the literal response.  Unfortunately, this rigging can confuse our decision-making and create subconscious biases.  Or we can use these responses to alter (control?) other people.  People have found all kinds of tricks to put people into an appropriate frame of mind to get what they want.


We still have much to learn about the brain itself.  We have even more to learn about the evolutionary changes to the brain which made us human.