Split Brain Research - Biological Psychology - Biological Psychology [AQA ALevel]

Summary

The video explores split-brain research, particularly Sperry's 1969 studies on patients who had undergone surgery to sever their corpus callosum as a treatment for epilepsy. The research reveals how each brain hemisphere has specialized functions, with the left hemisphere responsible for language and the right for recognizing faces. It highlights how the separation of the hemispheres creates two distinct, independent systems of thought. Despite some criticisms of the methodology, the study has deepened our understanding of consciousness, suggesting that our sense of self may be a collaboration of multiple intelligent processes.

Takeaways

• 🧠 The brain is contralateral, meaning the left hemisphere controls the right side of the body and vice versa.
• 🔍 The corpus callosum connects the two hemispheres, allowing them to communicate through 200-300 million nerve fibers.
• ✂️ Cutting the corpus callosum stops communication between the hemispheres, which was once done to treat severe epilepsy.
• 🗣️ The left hemisphere contains language centers, so split-brain patients can only verbally identify objects seen by the right visual field.
• 🖼️ The right hemisphere is better at recognizing faces, as demonstrated by showing different faces to each hemisphere.
• 🧩 Sperry's split-brain research showed that each hemisphere can function independently, highlighting the brain's specialization.
• 🔬 Some criticisms of Sperry's research include the small sample size, variability in disconnection, and potential influence of drug therapy.
• 🌍 The findings may not fully apply to real-world situations, as everyday life allows both hemispheres to access information by moving the eyes.
• 🧩 The research expanded our understanding of consciousness, suggesting the brain may consist of multiple independent processes working together.
• 🤚 Split-brain patients can sometimes experience alien hand syndrome, where one hand behaves independently, seemingly controlled by another mind.

Q & A

What is the function of the corpus callosum in the brain?

The corpus callosum is a thick bundle of 200 to 300 million nerve fibers that allows quick communication between the left and right hemispheres of the brain.

What happens if the corpus callosum is cut?

If the corpus callosum is cut, communication between the left and right hemispheres is stopped. This can reveal how each hemisphere is specialized for different functions.

Why was cutting the corpus callosum performed in some patients?

The procedure was performed to treat severe epilepsy, with the goal of stopping electrical seizures from bouncing between the hemispheres and reducing the frequency of seizures.

What did patients report after undergoing corpus callosum surgery?

Patients generally reported few side effects, though some experienced a strange sense of being 'two people in one body.'

What did Sperry’s 1969 split-brain research involve?

Sperry’s research involved studying patients who had their corpus callosum cut. His divided field experiment tested how the brain hemispheres function independently by showing words or images to different visual fields.

How did split-brain patients respond when different words were shown to each visual field?

When words were shown to the right visual field (processed by the left hemisphere), patients could say the word because the left hemisphere controls language. However, when shown to the left visual field (processed by the right hemisphere), they could not say the word but could draw or identify it with their left hand.

What did Sperry's research reveal about the hemispheres' specialization?

Sperry's research showed that the right hemisphere is better at recognizing faces, while the left hemisphere is specialized for language and speech.

What are some criticisms of Sperry’s split-brain research?

Criticisms include the small sample size, the use of epileptic patients who may have had abnormal brains, the varying levels of disconnection between hemispheres, and the potential influence of drug treatments on the results.

What is alien hand syndrome, and how does it relate to split-brain patients?

Alien hand syndrome is a condition where one hand acts independently, seemingly under the control of another mind. It can occur in split-brain patients, where one hand may act against the other, as if controlled by a separate consciousness.

What philosophical insight does split-brain research provide about consciousness?

Split-brain research suggests that consciousness may not be a unified entity but rather a collection of separate intelligent processes working together, which has implications for both psychological and philosophical understandings of the mind.