Things are about to get complicated here as I mix some metaphors up. To begin I will post this optical illusion developed by Gestalt psychologists in the early 20th century. They used it to illustrate that the brain’s visual perceptual system can operate with one gestalt at at time.
You can focus on either the faces or the chalice but not both at the same time; one figure must be relegated to ground in service to the other. The gestalt theorists gave us a really good and useful concept there. Simple enough.
Focus on the chalice for a moment. Our biological roots have culminated in our symbolic capability. Symbols carry meaning, so we must create meaning. Symbols represent things even if those things are conceptual in nature; nothing like quarks or multiverses or Higgs fields or Zeus out there really. For me the holy grail of neuroscience is to understand how our brains make meaning using symbols. This may not be possible; it will certainly not be done easily. Other goals, like understanding psychiatric disorders, are more important, but still, the pure science of the matter is that we seek to understand the basis of our humanity and this basis derives from our symbolization ability. More later.
Focus on the faces for a moment. Long years ago I became fascinated with conversations, the linguistics, the pragmatics, the paralinguistics of conversations. Exceedingly commonplace with an endless variety of purposes and forms, conversations require that symbolic processing proceed rapidly, fluently, accurately about topics that are more often displaced in time and space and not immediately evident to our senses. We converse by understanding another and expressing ourselves and the power and facility with which we do this is amazing. Working as a speech/language pathologist I worked with children facing various challenges in conversing but they all wanted to converse just like they wanted to walk. Conversing is in our nature and of course it is biological. More to come.
So the optical illusion is a metaphor for the holy grail of neuroscience, symbolization, and for perhaps the most pervasive distinctively human behavior of all, conversation. One is ground for the other’s figure. Stay tuned.