72 ROBERT M. YERKES 



Conditions of Experiment from Day to Day for Problem 2 — Continued 

 Date Punishment Reward 



June 17 (1st series). 60 sec. confinement Food (banana, as in early 



series) 

 " 17 (2nd series). No confinement in wrong box; Food only for correct first 



but instead, return to start- choices 



ing point by way of alleys 

 " 18 to 22 No confinement in wrong box; Food only for correct first 



but instead, return to start- choices 



ing point by way of alleys 

 " 22 (2nd series). No punishment; allowed to en- Food for each trial 



ter boxes until right one was 



found 

 " 23 Return to starting point. After 



five wrong choices of a given 



box the animal was held for 



60 sees, in one of the boxes 



and was then released by 



way of the exit door and 



rewarded when the right one 



was chosen 



" 23 (2nd series). No punishment Reward for each trial 



" 24 (1st series). Return to starting point Food only for correct first 



choices 



" 24 (2nd series). No punishment Reward for each trial 



" 25-30 Same as on 24th 



July 1 (1st series). No punishment " " " " 



" 1 (2nd series). Return to starting point Reward only for correct first 



choices 



" 2-8 Same as on July 1 



" 8 (2nd series). No punishment Reward for each trial 



" 8 (3rd series). Return to starting point Reward only for correct first 



choices 



" 9-10 Same as for July 8 (3rd series) 



" 10 (2nd series). Momentary confinement in Reward for each correct choice 



wronj. boxes 



" 12 Return to starting point Reward for correct first choice 



" 12 (2nd series). 30 sec. confinement Reward for each correct choice 



" 12 (3rd series). 5 " " " " " 



"13 30 " " " " " 



" 14-17 Return to starting point Reward for correct first choices 



" 17 (2nd series). 60 sec. confinement Reward for each correct choice 



"19 30 " " " " " 



" 20-26 10 " " " " " " " 



" 27-30 Right box indicated by slight Reward in each right box 



raising of exit door momen- 

 tarily. No punishment 



" 30 (2nd series). Return to starting point Reward for correct first choices 



"31 " " " " " " " " " 



" 31 (2nd series) 



to Aug. 10. . 10 to 60 sec. confinement Reward for each correct choice 



Aug. 10 (2nd series). Threatened with whip " " " " " 



" 11 (1st series). " " " " " " " " 



" 11 (2nd series). 10 sec. confinement " " " " " 



" 12 Threatened with whip " " " " « 



" 12 (2nd series). 10 sec. confinement " " " " " 



« ig 10 " " " " " " " 



" 19 (2nd series). Threatened with whip..'... .. " " " 



