The model (Eq. 1) has three parameters (L, W, S), the reading rates of the letter-by-letter, whole-word, and sentence-context processes. For each condition, the model predicts a reading rate (word/min) that is the sum of the rates of the spared processes. For each of 11 observers, we measured reading rates for all eight possible combinations of knockouts. The model was fit, separately, to the data for each observer. This table shows the model fit. The observer data are shown in Table 1. The fit's mean±SD, across observers, is shown for each condition. (The SE is about one third the SD.) The model fits every observer well (Table 2). The overall RMS error, across conditions and observers, is 22 word/min. The excellent fit of the additive model (Eq. 1) proves triple dissociation with a combination rule of summation [37].