1956 Volume 6 Pages 75-82
The maze turning behavior of Armadillidum vulgare, a terrestrial isopod crustacea, was studied in order to test the possible operation of C. L. HULL's principle of reactive inhibition. The mazes used for the experiments were made of frosted glass plates and were shown diagrammatically in Figs. 1, 2 and 3. The number of animals turning right or left at T choice-points was counted for each maze. Experiments were carried out in dark-room under constant illumination. The results obtained were summarized as follows :
(1) The distribution of right or left turns at a T choice-point preceded by a straightaway approach agreed exactly with chance expectancy.
(2) The strong tendency of alternation of turning directions at succeeding T choice-points was clearly observed.
(3) When an animal approached a T choice-point along a pass requiring two preceding right turns (two-turn maze), the tendency of its turning in opposite direction was further enhanced in comparison with the situation of only one preceding right turn (one-turn maze).
(4) In the one-turn maze, as the length of straightaway between T choice-point and its preceding right turn (OF in Fig. 2) was increased, the opposite turning tendency at T choice-point became less pronounced, and in the case of 16cm length, the effect of preceding turning was not recognizable and the distribution of right and left turnings at T choice-point closely approximated chance expectancy.
(5) In the two-turn mazes, the increase of length of straightaway, may it be either of F2T or F1F2 in Fig. 3, had an effect of decreasing the tendency of the animals to turn in the opposite direction at T choice-point. However, the straight-away as long as 16 cm, which was enough to diminish the acquired tendency of alternative turning in one-turn maze, was not sufficient to diminish the effect of preceding turning in two-turn mazes.
The results above mentioned are all be interpreted as conforming the expectation based upon the reactive inhibition principle.