52 JOSEPH PETERSON 



1. The decrease in the percentage of returns by the animal 

 emerging from blind alleys is very rapid in the early part of the 

 learning, and as a rule the rat continues to enter blind alleys, 

 even to their full length, long after returns are discontinued; 

 i. e., the curve of returns from blind alleys drops much more 

 rapidly than that representing the number of entrances to blind 

 alleys. These returns persist longer in the case of cul de sacs 

 encountered along the first part of the correct path than in that 

 of those nearer the food box. 



2. The elimination of entrances to blind alleys does not come 

 •about mainly by a decrease in the number of entrances, but 

 principally, especially in the case of the longer cul de sacs, by 

 a gradual decrease in the degree, or the distance, of entrance. 

 Just before entrance is eliminated completely, there frequently 

 occurs a peculiar and very rapid vibration of the rat's head 

 between the direction of the true path and that of the tempting 

 blind alley. Frequently, after the first success in passing any 

 such blind alley, the rat runs headlong into some cul de sac 

 farther along the correct trail, which it had previously learned 

 to avoid. These and other facts of similar import indicate 

 that the maze is learned "as a whole " to a large extent, and 

 that entrances to blind alleys are not properly to be regarded 

 as separate acts, as is frequently done in speculations on learning. 



3. Entrances to short cul de sacs are eliminated more readily, 

 other things equal, than entrances to long ones. Not only are 

 the total entrances to the short blind alleys fewer than to the 

 longer ones, but the percentage elimination of them is greater. 

 The curve of decrease of entrances drops more rapidly in the 

 case of short than in that of long cul de sacs. 



4. Blind alleys first to be passed along the true path are 

 entered more frequently than those further along — nearer the 

 food box — and their percentage rate of elimination is less. That 

 is, entrances to the first cul de sacs encountered are more persis- 

 tent, harder to overcome, than those to cul de sacs nearer the 

 food box. 



5. With untrained rats the number of returns toward the 

 entrance door in the maze, on the rats' emergence from blind 

 alleys, nearly, if not quite, equals in the beginning of the experi- 

 ment the number of cases of keeping the general forward direction 

 toward the food box. It appears that at the beginning stage 

 of learning in the maze mere probability determines whether 



