Julie Holland: Can we start with the catnip story?

Michael Pollan: I always kept a little patch of catnip in my garden for my old tomcat, Frank, who really liked it. It’s not a very difficult plant to grow. The patch was hard to miss, because it was so shrubby. But every evening around five or six o’clock, just around the time that I was going to the garden to harvest something for dinner, Frank would come down there and look at me. What he wanted to know was where that catnip was, because he managed to forget every single night. And I would point it out to him or sometimes bring him over to it, and then he would pull some leaves off, sniff them, eat them, and start rolling in the grass. He was clearly having a powerful drug experience. Then he would sneak away and sleep it off somewhere.

But the interesting thing was, as much as this became part of his daily routine, he could not remember where the catnip was. And it occurred to me that this might be a kind of evolutionary strategy on the part of the plant: instead of killing the pest, it would just really confuse it. Killing pests can be counterproductive, because they breed or select for resistance very quickly. This happens with a lot of poisonous types of plants, as it does with pesticides. But if the plant merely confuses the pests or disables their memory, it can defend itself against them overindulging. Pure speculation, as I say in the book. It occurred to me that it might help explain what’s happening with cannabis, which of course also disables memory.

Holland: So THC could potentially protect the plant from pests by discombobulating them so they forget where they found it?