Trial and error learning in paramecium: a replication.

Single paramecia were sucked into a capillary tube and allowed to escape back into a drop of their culture. Escape speed increased in early trials and then stabilized, thus replicating French's 1940 results, and supporting his hypothesis of learning in paramecia. Further, neither intertrial interval nor habituation to the drop changed the rate at which escape improved, though habituation increased escape speed over all trials.