“Fathoming Unconscious Depths” is the second chapter in “Consciousness and the Brain Deciphering How the Brain Codes our Thoughts’” an outstanding book by the French neuroscientist Stanislas Dehaene who is the Chair of Experimental Psychology at the College of France. This is the third consecutive post on this important book.
Sigmund Freud is generally credited for the discovery of the dramatic amount of mental processing occurs outside our awareness. Dr. Dehaene has disabused me of this notion. Hippocrates (ca. 129-200) wrote a treatise on epilepsy, “The Sacred Disease,” in which he noted that the brain constantly controls us and covertly weaves the fabric of our mental life. Indian and Arab Scholars not only preserved some of antiquity’s medical wisdom, but made advancement’s of their own. The Arab scientist, Alhazen (Ibn al-Haytham, 965-1040) whom we have met in a previous healthymemory post (Understanding Beliefs) discovered the main principles of visual perception. Centuries before Descartes, he understood that the eye operates as a camera, a receiver rather than an emitter of light, and he foresaw that various illusions could fool our conscious perception. Consciousness was not always in control, Alhazen concluded. He was the first to postulate an automatic process of unconscious inference; unknown to us, the brain jumps to conclusions beyond the available sense data, sometimes causing us to see things that are not there.
Questions crucial to delineating the unique contributions of conscious thought are how deep can an invisible image travel into the brain? Does it reach our higher cortical centers and influence the decisions we make? Recent research in psychology and brain imaging have tracked the fate of unconscious pictures in the brain. Masked images, images that have been experimentally obscured are recognized and categorized unconsciously. We even cipher and interpret unseen words. Subliminal pictures trigger motivations and rewards in us, all below our level of awareness. Complex operations linking perception to action can unfold covertly, demonstrating how frequently we rely on an unconscious automatic pilot. Being oblivious of these unconscious processes, we constantly overestimate the power of our consciousness in making decisions. The truth is that our capacity for conscious control is limited.
The answer to the question as to which regions of the brain participate in conscious and unconscious processes, the answer is both simple and surprising. Virtually all the brains regions can participate in both conscious and unconscious processing.