Madness

Consider five chimps. Place them in a large enclosure. Suspend some bananas from the roof. A stepladder should be provided for the chimps. However, attach a proximity detector to the bananas so that when a chimp approaches the banana, the water hoses are activated and the entire cage is saturated.

The chimps quickly learn to ignore the bananas and the stepladder.

Remove one of the chimps and replace it with a new one. The chimp has no idea what hoses are. He sees the banana, notices the stepladder, and imagines himself reaching the golden nourishment.  He then retrieves the ladder... and the four other chimps charge - a thorough thrashing follows. He too learns to forget the stepladder.

After that, take another chimp out and replace it with a new one. The scene repeats again; when he reaches for the stepladder, he is attacked by the four other chimps, including the preceding "fresh" chimp. He has incorporated the principle of "do not touch the stepladder."

Iterate. After a few procedures, you have five chimps who are ready to punch any chimp who dares to touch the stepladder  — and none of them knows why.