What Percentage of the Brain Does What?

August 23, 2010 — Note: Sometimes I'll write a post about something I don't understand at all. I am not a neuroscientist and have only the faintest understanding of the brain so this is one of those times. Reading this post could make you dumber. But occasionally writing from ignorance leads to good things--like the time I wrote about Linear Algebra and got a number of helpful emails better explaining the subject to me.

My question is: how are the brain's resources allocated for its different tasks?

In a restaurant the majority of the workers are involved with serving, then a smaller number of employees are involved with cooking, and still a smaller number of people are involved with managing.

The brain has a number of functions: vision, auditory, speech, mathematics, locomotion, and so forth. Which function uses the most resources? Which function uses the least?

I have no idea, but my guess is below.

• 1. Vision. My guess is vision uses more than 50% of the brain.
• 2. Memory. Perhaps 50% or more of the brain is involved with storing memories of sights, sounds, smells, etc.
• 3. Locomotion. Movement probably touches between 20-60% of the brain.
• 4. Auditory/Speech. I guess that between 20-40% of the brain is involved with this.
• 5. Taste/touch/smell. My guess is between 10-20%.
• 6. Emotion. My guess is 10-15% is involved with setting/controlling emotion.
• 7. Long term planning/mathematics. I think the ability to do complex thinking is given the least resources.

I'm probably quite far off, but I thought it was an interesting question to think about. Now I'll go see if I can dig up some truer numbers.