76 8 14 3 19 4 7 78 5 20 6 14 4 5 86 13 22 5 12 3 9 75 4 15 8 19 4 13 77 7 11 11 29 11 12 87 12 22 9 20 4 9 AV. 8.2 17.3 7.0 18.8 5.0 9.2 LABYRINTH C LABYRINTH B LABYRINTH D 58 16 -- 2 14 7 10 60 17 -- 13 37 10 14 88 25 35 9 22 4 8 49 34 -- 1 5 7 8 57 15 -- 3 20 3 6 85 11 18 2 11 3 4 AV. 19.7 26.5 5.0 18.2 5.7 8.3 The results are sufficiently definite to warrant the conclusion that experience in B rendered the learning of C easier than it would have been had there been no previous labyrinth training. Those individuals whose first labyrinth training was in C made their first correct trip as the result of 19.7 trials, whereas those which had previously been trained in labyrinth B were able to make a correct trip as the result of only 7.0 trials. Similarly the table shows that training in C rendered the subsequent learning of B easier. To master B when it was the first labyrinth required 8.2 trials; to master it after C had been learned required only 5 trials. In addition to proving that the acquisition of one form of labyrinth habit may facilitate the acquisition of others, comparison of the averages of Table 51 furnishes evidence of the truth of the statement that no results of training can be properly interpreted in the absence of knowledge of the previous experience of the organism. CHAPTER XVII INDIVIDUAL, AGE, AND SEX DIFFERENCES IN BEHAVIOR All dancers are alike in certain important respects, but to the trained observer of animal behavior their individual peculiarities are quite as evident, and even more interesting than their points of resemblance. Omitting consideration of the structural marks of individuality, we shall examine the individual, age, and sex differences in general behavior, rapidity of learning, memory, and discrimination, which have been revealed by my experiments. Observations which bear on the subject of differences are scattered through the preceding chapters, but in no case have they been given sufficient prominence to force them upon the attention of those who are not especially interested in individual peculiarities. It has seemed worth while, therefore, to assemble all the available material in this chapter for systematic examination and interpretation.