Scottish Rugby Union director of rugby Jim Telfer believes nature must run alongside nurture in his search for more abrasion in the Scottish pack.
Edinburgh Gunners lock Nathan Hines has been selected ahead of Stuart Grimes for the second successive RBS 6 Nations game against Italy at Murrayfield.
Hines played in the 40-9 defeat by England last weekend and will partner club-mate Scott Murray in the second row against the Italians as Scotland seek to avoid the wooden spoon.
But, despite winning just once - against Wales - so far in the competition, Telfer insists the Scotland coaching staff have no complaints about the effort being made by the players.
He said: "There are two ways about getting devil in the pack.
"You can try and make an individual more aggressive but that is not down to me, it is to do with what their mother and father put into them.
"The other way is to change the personnel and put more aggressive people in.
"Ross Beattie is abrasive, young and fairly inexperienced at that level and still has a lot to learn.
"So I will never be satisfied with the aggression of the Scottish pack.
"To be fair to the players we have got, they are giving us total commitment and that is all we can ask for."