system
Given the following post, respond as if you're commenting on Reddit:
human
Why was cephalization an evolutionary advantage? Did quicker information processing between senses outweigh the chances that multiple nervous centers could be destroyed at once?
gpt
One key concept to remember in evolutionary biology: the search space for potential adaptations is effectively infinite, so you will almost never find the "best" solution for any problem. What you tend to find is the first serviceable solution, which is then improvised upon and gradually improved.

Whether or not cephalization is "best", it probably has some evolutionary advantages of simplicity.  Is it easier to make 5 separate brains, or is it easier to just have one brain grow much bigger? Probably the one-brain solution.  Once you've got a single big brain, is it easier to make that one big brain smarter? Or is it easier to break it all and start over trying to develop a distributed brain?  Almost certainly better to just improve on the already-existing brain.

The advantages for processing speed for a centralized brain may be incidental, or they could be the driving force, it's pretty hard to say and might need some complicated modeling to see if one method is much better or not.  Even if the distributed model were better, it would be starting at square one right now.  It would be hopelessly un-evolved and would be badly outgunned when competing against smart and aggressive cephalized animals.