Full Idea
The idea running through the work of Aristotle, Kant, Anscombe and Davidson is that explanation of action involves justifying that action or making it rationally intelligible.
Gist of Idea
A standard view says that the explanation of an action is showing its rational justification
Source
Rowland Stout (Action [2005], 5 'Psychological')
Book Reference
Stout,Rowland: 'Action' [Acumen 2005], p.69
A Reaction
Stout goes on to say that instead you could give the 'rationalisation' of the action, which is psychological facts which explain the action, without justifying it. The earlier view may seem a little optimistic and intellectualist.