Figure 4. Retention with respect to repeated learning¹⁵.

The blue lines and green lines are the fresh stage and working stage of learning, respectively. The dotted black lines are our forgetting curves. The learning stages are much shorter, and if the horizontal axis scale magnified the shapes of learning curves are like the creeping stage of Fig. 1. The 6 points of test data are not shown in the figure, because their vertical values are all 100%.