The concept of free will and consciousness had been significantly challenged by spilt brain research, particulate through studies involving the corpus callosotomy, s surgery aimed at treating severe epilepsy by severing the corpus callosum, which connects the brain hemispheres. This procedure revealed profound insights into how the left and right hemispheres function independently in some aspects, raising questions about identity, decision making and free will.
Pioneering experience by Roger Sperry and Michael Gazzaniga
Pioneering split- brain experiments led by neuroscientists Roger Sperry and Michael Gazzaniga demonstrated that after the hemispheres were isolated, patients’ brains seemed to operate with two separate entities. The left hemispheres, typically associated with language, could process verbal instructions, while the right hemisphere, responsible for more visual and emotional tasks, could respond non- verbally. For instance, when images were shown to the right hemisphere, patients could not verbalize what they saw, but could point to the object with their left hemisphere. This showcased the different cognitive roles each hemisphere plays and how they can function independently in certain context.
The role of the Corpus Callosum in Cognitive function
Before this research, it was debated whether the corpus callosum was crucial for brain processing or just structural. Early evidence forms surgeons like Walter Dandy and William P van Wagenen suggested that severing the corpus callosum did not immediately affect cognitive abilities, but Sperry findings revealed deeper complexities in brain function. His work helped solidify the idea that while basic functions like motor control and sensory processing don’t rely on one hemisphere, more complex tasks such as language and spatial reasoning are specialized.
Hemispheric specialization and independent process
One of the most striking aspect of split-brain research was how the left hemisphere, with its interpreter module tries to make sense of actions controlled by the right hemisphere. For example, in an experiment where one hemisphere saw a chicken claw and the other saw a snow scene, a patient would point to both a chicken and a shovel. When asked why, the left hemisphere would justify the shovel choice by the saying it was for cleaning the chicken coop, even though the right hemisphere, which had seen the snow scene, had made the decision. This shows how the left hemisphere creates coherent narratives to explain behavior, even when it lacks full information.
The left Hemispheric interpreter module: creating coherent Narratives
This research also demonstrated how each hemisphere processes emotional triggers differently. In one case, a patient who saw a disturbing image with the right hemisphere felt uneasy but could not explain why, as the left hemisphere had not seen the image. This shows how emotions ca be processed separately form conscious reasoning. These findings suggest that our brains are constantly justifying actions and emotions, often without our conscious awareness.
The brain interpreter module and subconscious justifications
This phenomenon is related to the brain interpreter module, which constructs explanations for behavior based on incomplete information. Similar to the Dunning- Kruger effect, where people overestimate their abilities in areas they know little about, the interpreter module can be confident in its justifications are often made by the brain before were consciously aware of them. This suggest that many of our actions are driven by subconscious processes, and the brain steps in afterwards to justify or explain what we have done.
Implication for understanding free will and personal identity
This understanding can be liberating, as it allows us to detach from notion that every thought or decision is fundamentally tied to our identity. Thoughts or impulses that arise subconsciously can be dismissed without internalizing them as core aspects of ourselves. It also highlights how our brain tend to avoid discomfort by justifying negative behaviors, such as when we feel resentment toward someone we’ve wronged. Recognizing this natural tendency can help break cycles of self- justification and improve personal accountability.
Determinism, neuroplasticity and the role of subconscious process
These discoveries challenge the idea of free will in a deterministic sense, where every decision is influenced by pre-determined neural patterns. However, this perspective does not entirely negate the concept of neuroplasticity the brain ability to change and adapt over time. While subconscious processes play a significant role in shaping behavior, we still have the ability to consciously reshape thoughts and habits through practice and self-awareness.
Reconciling free will with brain function
One way to reconcile the tension between determinism and free will is through emergence theory, which suggests that complex system, like the brain, give rise to new properties (like consciousness) that cannot be fully explained by their individual components. In this view, neurons firing together create patterns that produce consciousness, in this view neurons firing together create patterns that produce consciousness, which then feeds back into those neural processes, shaping future thoughts and actions. While many behaviors are shaped subconsciously, we have the capacity to influence and adapt our responses over time.
In conclusion, split- brain research has reshaped our understanding of consciousness, decision making, and free will. While the brains hemispheres can function independently, they work together to create a unified sense of self, albeit through a complex interplay of subconscious processes and rational justifications. This understanding often both humility in recognizing our cognitive limitations and freedom in consciously shaping our thoughts and behaviors.
By
Dr. Abid Hussain Nawaz, Ph.D. & Post Doc
Rumana Gull, Scholar Master of Philosophy Biological Sciences
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