110 CARNEGIE INSTITUTION OF WASHINGTON. 



more records in the last 7 days above 50 per cent correct per day than of 50 

 per cent and under; this indicates a somewhat stronger tendency to go towards 

 than away from the light, but none of the dogs has approached formation of 

 full association of the light with food. The two litters gave, in general, like 

 results in the training with light signals. 



"During the training with the light signals, certain positive habits were 

 developed that very seriously interfered with the progress and analysis of the 

 behavior. In spite of special training to eliminate these habits the subsequent 

 behavior was complicated by the probable continued effect of these habits 

 in varying degrees. 



"Another litter of five 6-month dachshunds was started at the first of the year 

 and trained in this apparatus for 3 months with the buzzer signals. At the 

 end of this time there was no indication that any association had been formed; 

 the number of correct trials per day fluctuated around 5 out of 10. In only 

 one case a record of 9 correct was made; in another case (a different dog) a 

 record of 10 correct. The subsequent behavior indicated clearly that these 

 cases were due to other causes than the formation of an association between 

 the buzzer and the food. The preliminary training was as similar as possible 

 to that given to the three litters which learned the association with the buzzer; 

 moreover, the failure of this litter to learn can not be ascribed to any family 

 difference, since the parents of this litter were from the same strain as the 

 successful litters. 



"A group of 4 chow-chow bitches was given the preliminary training in this 

 apparatus. In spite of great differences in their ages and experiences they 

 all failed to master the necessary preliminary routine of the apparatus; even 

 after three months of training. 



"Since this apparatus was planned to test the relative ability of different 

 breeds to form associations with a series of different types of signals, and 

 since no indications have been found of any association with strong light 

 signals, and, further, since three months is not a long enough time to form 

 the sound associations in a litter from the stock that had previously given 

 three litters that did learn them, and since the chow-chows tested were not 

 amenable to the necessary preliminary training, it becomes clear that this 

 apparatus provides an unsatisfactory method of testing native tendencies as 

 the basis for genetic studies. 



"Jumping test. — In searching for suitable tests for measuring family and 

 racial characteristics in dogs, an apparatus was constructed to find the height 

 from which a dog would jump. It was an elevator consisting of a closed 

 box operated by block and pulley, running up and down on tracks that reached 

 up to a height of 20 feet. The test was started with the height 2 feet; in 

 practically all cases the dog jumped immediately when the door was raised; 

 so no preliminary training was necessary. After jumping, the dog was re- 

 turned to the house, and the next one in the litter was tested at the same 

 height. In this manner all the dogs in a litter were put into the elevator at 

 successive heights of 2, 3, 4, 5, etc., feet, until the limit was reached. No 

 special reward was given to stimulate the jumping, since up to a certain 

 height all the dachshunds were anxious to jump down. The test for a dog 

 was concluded for the day when he sat for 20 minutes without jumping. The 

 test was repeated every two months. The records gave the height jumped, 

 the time between the opening of the door and the arrival in the straw bed, 

 and the vocal behavior of the dog. Three litters of dachshunds and four 

 chow-chow bitches were tested by this method. 



"Certain general results were found. There is a strong tendency for a dog 

 to take longer before jumping as the height increases; also, at increasing 



