What if your brain hemispheres are disconnected – Two Examples

In my article about left and right brain and the functions of these hemispheres I want to give you some examples of what if the link between the two brain hemispheres is cut.

Example 1

Here is an example of what happens if the brain hemispheres are disconnected to each other as it is the case for split brain patients. Relating to that a split brain patient who covers his left eye while reading a word such as “telephone” on a screen only with his right eye is able to read that word out loud since the that stimulus will be processed by the left brain hemisphere. This is due to the focus on language of the left brain hemisphere. 

However, if that same person covers his right eye in way that he only sees something through his left eye, he won’t be able to speak about that word he just read on the screen. Regardless of the complexity of the word; it can be quite simple such as “computer”. The person won’t be able to name it since he only read it with his left eye and everything seen by the left eye is processed in right brain hemisphere which is not related to language. But yet, here is the fun part of that experiment. If you ask the person to draw the word he just read, he will do so; in our case “a computer”. And first after recognizing that picture with the right eye, the brain is able to formulate it into language and say it out loud. 

Example Two

There has been an artist named Giuseppe Arcimboldo from the 16th century who drew portraits of people made out of fruits, vegetables or books. If you look at that picture, you will always recognize both, the face and the vegetables. However, the split brain patient will only recognize that there is a face if he covers his right eye. This is due to ability of processing emotional data from the right side of the brain. An individual is able to express feelings with its face and the observer is able to determine the feeling based on the mimic expression. For that reason facial expressions are processed by the right hemisphere, the emotional part of the brain. In the case of the split brain patient, you can keep asking the patient whether he recognized the vegetables and he will always deny. But let’s assume the opposite is the case. The patient covers his left eye and has a look at the drawing with his right eye. The information received by the right eye is now processed in the left brain hemisphere (the analytical part). Accordingly the patient won’t recognize the face anymore but the vegetables instead. So now he is more focused on the details of the picture and the overall meaning gets lost. You can even ask the patient to look closer in order to see the face; he just won’t recognize it since the received information by the right eye is only processed by the left brain. 

But usually the brain hemispheres are connected to each other which makes it on the one hand hard to understand how these patient aren’t able to recognize those things and on the other hand we now see that due to the connection of the two brain hemispheres, we always recognize the whole picture and not just one single aspect of it.