Before Tim Burton's Batman was released in 1989, the only live-action exploration of the Dark Knight was relegated to Adam West's iconic, albeit campy portrayal of the character. Before Burton took on directorial duties, there was no deep complexity to the character on screen that focused on what would motivate someone to dress up as a bat and fight crime. While Batman did a great job exploring this idea, it wouldn't be till decades later that another key component revealed itself in defining the character's motivations.
Source：https://www.cbr.com/batman-cowls-share-secret-motivation/
