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. Author manuscript; available in PMC: 2009 Oct 1.
Published in final edited form as: Pharmacol Biochem Behav. 2008 Oct;90(4):778–786. doi: 10.1016/j.pbb.2008.05.022

Figure 2.

Figure 2

(a) Mean (±SEM) numbers of PCP deliveries, (b) mean (±SEM) adjusted delay (seconds), and (c) mean (±SEM) number of total choices as a function of FR requirement. Divided bars show numbers of smaller, immediate reinforcer choices (white section) and larger, delayed reinforcer choices (black section). Data represent the means of 6 sessions obtained in the group of 8 monkeys, except at FR 96, for which only 6 of 8 monkeys were tested. Solid horizontal lines between bars indicate P < 0.05 and dashed lines indicate P < 0.01. *P < 0.05 and **P < 0.01 compared to FR 8. #P < 0.01 compared to smaller, immediate reinforcer choices.