Gurdurr have long been viewed as among the dumbest of the world's pokemon. According to popular wisdom, Timburr are fairly unintelligent pokemon, and Gurdurr are at their smartest soon after evolution. Their intelligence then deteriorates because Gurdurr typically carry their steel beams directly over their head, and these enormous beams are too heavy for even a Gurdurr to securely carry. Whenever they drop a beam, a lump forms on their head to mark the wound, and their intelligence decreases from the trauma.
This understanding of Gurdurr has a long history in Unovan culture, and comparisons to these pokemon have long played a role in discussions of brawn vs. brain. Indeed, Gurrdurr's very name has contributed sounds which represent stupidity to many a language. It is also completely wrong. The lumps on Gurdurr's head are not bruises, but a natural shock absorber, and Gurdurr's brain is lower in the head than many fighting pokemon precisely to prevent brain damage. Construction workers have long ridiculed this interpretation, for few would allow any creatures as dumb as Gurdurr supposedly were to handle equipment far heavier and dangerous than even their steel beams. They have noted that Gurdurr follow instructions precisely, whether building high towers or wrecking the right buildings with such perfect control that even adjacent, much lower lots are never harmed.
Perhaps the myth developed because Gurdurr are far physically stronger than humans, and also have the opposable thumbs and penchant for tool use that many wild pokemon lack. Ancient humans sought a way to explain their superiority in dominating the world, noticed Gurdurr's lumped head and tendency to drop their beams, and a long-lasting myth was born. Or perhaps humans, who must often choose to train strength or knowledge, simply projected stupidity onto an extremely muscular pokemon.