The Zogbians, after extensive research, discovered that the species dominating this planet, humans, had an unusual susceptibility to a certain plant growing abundantly on their planet. This plant, known as cannabis, or more popularly, marijuana, had fascinating effects on the human brain. It could alter perceptions, enhance creativity, and in some cases, as the Zogbians were keen to explore, it could also induce a state of dumbfounded stupor.

Eager to test their theory, the Zogbians decided to introduce more cannabis into the lives of humans. Using advanced technology indistinguishable from magic, they began to increase the growth rate of marijuana plants around the world, making sure it was easily accessible in every corner of the globe.

The experiment was set in motion. Humans, intrigued by this sudden abundance of cannabis, started to consume it at an unprecedented rate. Philosophers philosophized with greater eccentricity, artists painted with unbound imagination, and the general populace seemed to enjoy the relaxed state of mind it brought about. However, as the Zogbians observed from their spaceship, they noticed a curious thing. Despite the burst of creativity and calm, there seemed to be a noticeable decline in the overall intellectual capacity of humans.

The fifth year of the experiment marked the height of the ‘Great Dumb Down’. Society seemed to have slowed down. The humans, once bustling with activity and progress, now seemed to be in a perpetual state of blissful ignorance, with their cognitive abilities significantly reduced. The Zogbians watched, amused, as their theory appeared to be confirmed. The aliens had indeed provided marijuana to the humans, and it had, in a way, made them stupider.