710 ROGER T. DAVIS AND ARNOLD A. McDOWELL 



Radiation schedule training 



Cross strings, box pattern, and angle cross patterns were presented twice 

 a day to each subject on all 12 days preceding irradiation. Thereafter, each 

 was trained once a day on parallel strings, double cross, and pseudocross 

 patterns, in addition to the three preirradiation patterns. 



No significant changes were attributable to radiation effects. 



The Elevator Detour Problem 



The elevator detour problem of McDowell and Nissen (1959) differs from 

 many previously reported in that it requires subjects to sustain and coordi- 

 nate the use of both hands during problem solution. The apparatus con- 

 sisted of an elevator and a ladder. The elevator was a wooden box covered 

 with Plexiglas, with the interior forming a shaft 18 in. high and 2 in. wide. 

 A small plastic elevator was mounted on two steel vertical rods and traveled 

 freely up and down the shaft. A stylus was attached to the front of the 

 elevator. The Plexiglas front was slotted so that subjects could raise the 

 elevator in the shaft to get a piece of candy resting on the top of the ele- 

 vator. A vertical ladder was mounted on the table of the WGTA 5.0 in. in 

 front of the restraining cage and 2 in. in front of the elevator. The monkey 

 had to reach through the rungs of the ladder to move the stylus. It could 

 view the candy through the Plexiglas as it raised the elevator, and, when the 

 elevator reached the top of the shaft, could procure the candy. Since the 

 elevator dropped if released, both hands had to be coordinated to pass the 

 stylus by each of the rungs of the ladder. 



Prelimiiiary training 



The shaft without the ladder was presented to the subject with the ele- 

 vator in three starting positions, 4, 8, and 12 in. from the top of the shaft, 

 until the subject could procure the candy five successive times at each posi- 

 tion. The ladder was then placed between the subject and the elevator shaft 

 during 10 days of training. Nine trials were given each day, three in each 

 starting position. The dependent variable was the latency of approach be- 

 tween presentation of the problem and subjects' response. If the subject 

 failed to approach the problem within 60 sec after it was presented, the 

 trial was called a failure-without-trying. If it tried to procure the candy 

 within 60 sec, but failed, the trial was called a failure-with-trying. 



Radiation schedule training 



The subjects received training with the ladder in place during the 12 days 

 before the first irradiation or sham irradiation. Training continued during 



