## 4 Methods
### Measuring Performance Inaccuracy
#### 4.4.2 Retention and Transfer Tasks  
In the immediate retention and transfer tasks, the participant played the test sequence along with a 90 ppm metronome. Here, a \"correct\" performance would constitute playing the correct notes in the expected sequence, as before, but with one caveat related to penalizing errors. Because these tasks were accompanied only aurally by a metronome beat, the performer might add an extra note or leave a gap so that all subsequent notes are then played one metronome beat late. In a situation such as this, it is reasonable to penalize the first late note, but not the subsequent notes, which are then correct subject to a delay. Similarly, a performer might skip a note, hence all subsequent notes will be a metronome beat early. As before, it is reasonable only to penalize the first pitch error.  
To establish which notes of the performed sequence were \"correctly\" pitched, we used the Note Time Playing Path software [34], which uses a windowing process to identify where extra, skipped, or substituted (wrongly pitched) notes occur. For performances where there were large numbers of pitch errors (\(>\)5), this matching process was visually confirmed.  
In order to count the total number of errors, we took a novel approach where only the first pitch error in a consecutive sequence of pitch errors was included. For example, consider a performer who plays the first four notes of a scale correctly (C, D, E, F). After this he/she plays three wrong notes in a row (D, D, E), but then returns to the original scale sequence one note after the last correct note (A, B). In this instance of four consecutive errors--three wrong notes (D, D, E) and one deletion (G)--only the first error is counted. The final penalty is then calculated by the total number of such \"first\" errors, designated by the letter \(E\) in Equation (2). This final error value is subtracted from an accuracy score calculated in the same manner as Equation (1) with the exception that it refers only to the correct notes in the performance. As before, the accuracy value is normalized by \(100/N\) to ensure a perfect performance of a melody of any length has an accuracy of 100, which means the formula to calculate a participant's inaccuracy in the retention and transfer tasks is  
\[Inaccuracy =100-Accuracy,\text{ where}\] \[Accuracy =\frac{100}{N}\Bigg{(}\bigg{(}\sum_{c=1}^{C}1-\frac{|t_{c}-t_{m}|} {333}\bigg{)}-E\Bigg{)}, \tag{2}\]  
and  
* \(N\) is the total number of notes in the target sequence.
* \(C\) is the total number of notes in the corrected performance.
* \(t_{c}\) is the time in milliseconds of the \(c\)th note in the corrected performance.
* \(t_{m}\) is the time of the metronome beat closest to the performed note \(t_{c}\).
* \(E\) is the number of errors calculated as explained above.  
We have defined two versions of _Inaccuracy_--one for the training tasks, one for the retention and transfer tasks. The context (e.g., in Section 2) will always make clear which of these is being used.  
[PERSON] is the recipient of an Australian Research Council Discovery Early Career Researcher Award (project number DE170100353) funded by the Australian Government. The authors would like to thank the [PERSON] for specially recoding Hex to make it respond to multitouch input.  
Drs [PERSON] and [PERSON] collaboratively conceived, designed and conducted the experiments reported in this article. Data was analysed and interpreted together. Both authors collaboratively wrote the paper.  
The authors declare no conflict of interest.