Cockroaches don't naturally care much for peppermint and vanilla, but with a little tutelage, the bugs will drool over them. Just like Ivan Pavlov’s dogs, who learned to associate a ringing bell with dinner, these roaches learned that the smell of peppermint and vanilla meant a sugar treat was on the way. More than a century after the original canine experiment, researchers have shown that insects can be taught to have a typically doglike response to the expectation of food: salivating.
To condition the roaches, Makoto Mizunami and Hidehiro Watanabe of Tohoku University first immobilized them on their backs in wax and then repeatedly introduced the smell of peppermint and vanilla before giving them sugar, which roaches adore. To test whether the vermin picked up the association, the researchers immobilized them in wax and measured their saliva output when peppermint and vanilla odors reached their antennae, which they use to ...
