51 



FIVE HUNDRED DAY RATS 



OBI 







UNIT 



10 20 30 40 50 



NUMBER OP TRIALS 



50 



70 30 



§5 



oa 



coo 



EH* 



•«a: 



UNIT = 10 



100 200 300 400 500 600 700 800 



TOTAL TIME (SECONDS) 



100 200 300 400 o<J0 600 700 800 

 TOTAL TIME ( CENTIMBTBRS) 



