Table 2. Classification accuracy determined by 5-fold cross-validation using all 186,355 features.

For each classification, the SVM classifier was trained in 80% of the data and tested in the remaining 20% to calculate accuracy. This process was repeated 5 times until each 20% data partition was used as a test set. Mean accuracy reflects the average of all 5 values of classification accuracy, while the range depicts the minimum and maximum accuracy for a given classification.

Classification	Mean accuracy	Range
1T–3T	68%	63%–74%
1T–5T	84%	73%–95%
1T–7T	87%	81%–93%
3T–5T	72%	68%–76%
3T–7T	81%	77%–89%
5T–7T	66%	63%–70%

Abbreviations: 1T, 3T, 5T, 7T: Working memory load representing 1-, 3-, 5-, and 7- letter conditions.