I'm doing research about how different conditions or situations affect the decision making process in chess. For example if the opponent's ELO ranking affects the average time used for every move. In the example, both variables are numerical and easy to obtain. However I struggle when it comes to define if a move is more passive or aggressive (specially after the opening theory).
I noticed that, independently of playing style, there are some external factors that make us play more actively (aggressively, taking more risk) or passively (defensively, taking less risk). I read some articles that say it depends on the current position and the analyzer "strength" to determine with certainty, but that is too subjective for my purposes. There must be some some objective cues to help me.
I was thinking about the mobility (as in how many moves the player or the specific piece have after the last move) or/and if it is making or stopping a threat. Are there other cues or methods I could use to define if a move is passive or aggressive?
Is there software where I can analyze a complete game and give me this kind of output? Perhaps not if the movement was aggressive, but maybe if it is making a threat or reaching more mobility than before?
I also know that some software like Chessmaster, uses AI "personalities" and some make passive or aggressive moves as their traits. Can someone explain how the software chooses a move that may not be optimal but a passive one?