Cross-comparisons used for training and testing
| Training: pointing versus grasping | Testing: pointing versus grasping |
|---|---|
| 1. Left hand, rightwards | Right hand, leftwards |
| 2. Right hand, rightwards | Left hand, leftwards |
| 3. Left hand, leftwards | Right hand, rightwards |
| 4. Right hand, leftwards | Left hand, rightwards |
Classifiers were trained and tested in the following cross-comparisons: (1) training: distinguish between observed grasping and pointing actions performed with the left hand towards the left; testing: distinguish between observed grasping and pointing actions performed with the right hand towards the right; (2) training: distinguish between observed grasping and pointing actions performed with the right hand towards the right; testing: distinguish between observed grasping and pointing actions performed with the left hand towards the left; (3) training: distinguish between observed grasping and pointing actions performed with the right hand towards the left; testing: distinguish between observed grasping and pointing actions performed with the left hand towards the right; (4) training: distinguish between observed grasping and pointing actions performed with the left hand towards the right; testing: distinguish between observed grasping and pointing actions performed with the right hand towards the left. In this way, the classifiers could use information related to the type of movement only. The four accuracies determined with (1), (2), (3), and (4) were then averaged.