Ashton, 25, was not on his best form during England’s 23-13 victory over France at Twickenham on Saturday.
Wesley Fofana's try for France focused attention on his less-than-watertight defence.
Stuart Lancaster said: "I think he's trying hard and working hard but equally he knows there are areas of his game he's got to work on.
"We've been talking to him about that. Like everyone else he'll be disappointed by the try Fofana scored."
Ashton's first-half try against Scotland was his only try in the last two Six Nations seasons, despite the fact that England won seven out of the eight games.