Maze Learning in Rats in the Absence of Specific Intra-Maze and Extra-Maze Stimuli, 1933 (; backlinks):
In an investigation of the sensory cues used by rats in the learning of a maze, Professor R. C. Tryon discovered that rats, after a slight initial disturbance, could run with their usual accuracy through the maze after being shortcut, that is, forced by means of blocks and a new shortcut path to leave out a part of the maze. This the rats could do in spite of the fact that all parts of the maze were interchanged and the rats were run in complete darkness.
A repetition of this experiment, Experiment 1, by the writer showed that, with blind rats on an elevated maze, some shortcuts were well executed while others were not.
The primary object of the present investigation was to discover the conditions under which shortcuts could be accurately executed.
In Experiment 2, an elevated 14-blind maze, all of whose parts could be interchanged one with another, was used. The maze was rectangular in general shape, with different arrangements of blinds in 3 corners. During the first 11 days of learning (two trials a day) the maze parts were not interchanged, the object being to see what effect a sudden change of maze parts would have on maze performance after the maze had been learned. Later, after the rats had learned the maze under constant shifting of maze parts, 9 different shortcuts were tried. The results of the sudden changing of parts and of the various shortcuts may be summarized as follows:
When the maze parts were suddenly interchanged maze performance was greatly disturbed, as indicated by the large increase in errors. The cause of the performance disturbance—whether it was due to the changing of specific stimuli that had become directive or to distraction—was not determined by this part of the experiment.
Shortcuts which greatly distorted the general rectangular shape of the maze were not executed accurately. These shortcuts were made by long diagonal paths placed between the adjacent sides of the rectangle.
Shortcuts which did not greatly distort the rectangularness of the maze were correctly executed. These shortcuts were made by short diagonal paths between adjacent sides and by short paths in place of the blind arrangements in the corners of the maze.
- “Put on” runs corresponding to each of the shortcuts, made by placing the rats by hand at a point on the maze which they reached after taking a shortcut, showed that the run from the habitual starting place and over the shortcut path was essential to accurate performance on the maze beyond the shortcut.
It was concluded that response in the maze is made, not to individual specific stimuli, but to groups of stimuli, and perhaps to wider patterns of groups of stimuli. Therefore, large disruptions of stimulus patterns, as by the long diagonal shortcuts, produced inaccurate performance while lesser disruptions had no important effect. If individual specific stimuli had been directive in the sense that each evoked a definite response, no shortcuts could have been correctly performed.
Finally, it was suggested that the essential nature of intelligent behavior is the capacity to respond adequately, that is, with a minimum of effort and without error, under conditions of changing stimuli.