Research links our capacity to act courageously (or the opposite) to measurable and controllable personal traits such as self-efficacy, self-esteem, the presence of anxiety, and the openness to experience. All these characteristics can be developed and shaped with practice and help.

Of course, the environment and context in which you are operating will also have a big influence.

Non-biological aspect such as our psychological makeup, values, and beliefs, along with conditioning by early role models, can compel us to act at risk to ourselves in the interest of protecting other people.