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. Author manuscript; available in PMC: 2005 Nov 14.
Published in final edited form as: J Exp Psychol Anim Behav Process. 2005 Apr;31(2):213–225. doi: 10.1037/0097-7403.31.2.213

Figure 6.

Figure 6

Proportion of responding on the FI 20-s schedule in the concurrent procedures of Experiment 2. Proportions are plotted as a function of the time elapsed since the beginning of the trial. Twenty-second trials (terminating with a reinforcer on the FI 20-s schedule) and 60-s trials (terminating with a reinforcer on the FI 60-s schedule) are shown separately. Data are averages from the last three sessions before a reversal, averaged over reversals. Horizontal dashed lines indicate indifference points; error bars are standard deviations. FI = fixed interval.