Change of heart, my ego providing competitive strategy (4,6)
I believe the answer is:
game theory
'competitive strategy' is the definition.
The answer and definition can be both related to thinking as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'change of heart my ego' is the wordplay.
'change of' indicates anagramming the letters.
'heart'+'my'+'ego'='heartmyego'
'heartmyego' with letters rearranged gives 'GAME THEORY'.
'providing' is the link.
Can you help me to learn more?
(Other definitions for game theory that I've seen before include "this might help with decision making" , "part of mathematics" .)