Complex sentence: The work is experimental and does not consider in depth the mechanisms by which performance is restored, whether it is because of an actual restoration of self-regulatory resources or provides an additional motivation to press on with a depleted self remains an open question.
Split into simpler sentences: The work is experimental and does not consider in depth the mechanisms by which performance is restored. Whether it is because of an actual restoration of self-regulatory resources or provides an additional motivation to press on with a depleted self remains an open question.