The ability of planarian worms to run a maze more successfully after being fed the remains of a successful worm (idea)

If any of these worms were truly smart, they'd see the little morsels of their brethren on the plate in front of them and decide that it's better to fail the maze.

Besides, it's been known for a while that animals, including humans, who eat each other's brains can get kuru, CJD, BSE, scrapie, or a host of other prion-related degenerative neurological diseases. That makes it not a very smart thing to do.