One summer long ago, I worked in a univeristy psych lab. It was a small lab run by two professors whose main research was about communication in rhesus monkeys. The way they treated the monkeys would today probably put these guys up in jail, but as I said, this was a long time ago.
That summer the professors read a journal article showing that planaria (flatworms) could be conditioned to swim or crawl a maze. My bosses decided to try to replicate thse experiments, so they bought some flatworms – I guess there must have been a planaria supply house. My job included their care, feeding, and conditioning. Feeding meant dropping a piece of beef liver in their tank for them crawl on and eat. The conditioning regime I was to follow involved putting each flatworm in a narrow, water-filled trough with electrodes at each end. I would then turn on a light, give the worm a few seconds to realize that the light was on, and then zap him. The worm would contract.
It was “classical conditioning.” The idea was that, like Pavlov’s salivating dogs, the worms would learn the light-shock connection and shrink when the light came on, before and even without the jolt of electricity.
It sounds easy, but there was one catch. How do you move a worm from the main tank to the experimental trough? Our technique was to suck the worm into an eye-dropper, then squirt him out into the trough. After the experimental session (I forget how many light-shock trials I hit them with each time), I would put the worm back using the same suck-squirt method.
The plan was that after we succeeded with the classical conditioning, we would move on to “operant conditioning,” teaching the little guys to run a maze – i.e., to turn right at the intersection.
We never got that far. The hardest part was keeping the planaria alive. Each morning I would check the tank and find a few of my charges getting paler and paler till they were translucent. We brought in new subjects, but they too failed to thrive. I figured that it was the combination of being squeezed through the narrow aperture of the eye-dropper and then being electrocuted.
Ever since, I have been extremely skeptical about reported findings on teaching flatworms anything. The monkey research was also bogus, but that’s another story.
