More on "Learning" in Paramecia

Reactions to light in four species of planaria.

“…In Lee's (1963) experiment, using C. foremani to demonstrate operant conditioning, experimental planaria and their yoked controls were stimulated by an intense overhead light until experimental iSs interrupted a weak light beam on the perimeter of the apparatus, thus extinguishing the overhead light. Although Lee's experimental animals interrupted this weak light beam more frequently than controls, Jensen (1965) has suggested that any interpretation of these results must consider the animal's readiness to come to rest after removal of the overhead light. In this connection, Jensen has argued that, although the yoking procedure controlled adequately for temporal patterns of stimulation, the experimental animals and controls differed markedly as to their location in the apparatus when the over-head light was extinguished: Extinguishing the overhead light should increase the animal's readiness to come to rest, and, while control animals could be anywhere in the apparatus, the reinforcement contingency insured that the experimental animals would be near the light beam so that on the next trial, when the overhead light again came on, they would be more likely to again interrupt it.…”

Discrimination Learning in Paramecia (P. caudatum)

“…Other relatively recent experiments that have dealt with this issue are those of Gelber (1952Gelber ( , 1956Gelber ( , 1957Gelber ( , 1958Gelber ( , 1962aGelber ( , 1962b, Jensen (1957aJensen ( , 1957b, and Katz and Deterline (1958). Gelber reported successful conditioned approach behavior to a sterile platinum wire inserted into a reservoir containing paramecia after the paramecia had received training with the wire coated with food (bacteria).…”

Possible Molecular Mechanisms for Paramecium Learning

“…Another attempt by Gelber in 1952 showed that paramecia that had been exposed to food sources (Aerobacter aerogenes) on tip of a platinum wire will learn to accumulate on the tip of platinum wire after a few trials [18]. Again, this study was challenged 5 years later by Jensen [19]. It was suggested that the so called learning was due to metabolite concentration gradient of the food source [19].…”

“…Again, this study was challenged 5 years later by Jensen [19]. It was suggested that the so called learning was due to metabolite concentration gradient of the food source [19].…”