Neuron magazine reports that people watched in an MRI machine could let a live snake closer to their heads if they "dissociated" from the feeling of fear.
"Courage is associated with dissociation of reported fear and somatic arousal." Somatic arousal being the physical agitation: pounding heart, sweat, etc.
In my view, anyone who can let a snake get near them in an MRI machine is already Batman.
But I do find the research potentially very useful to me. Essentially, it is to put the feelings aside. We've all done that, putting an emotion aside in moments when "the show must go on." So everyone knows how. Probably courage is a matter of being conscious and practiced at "not feeling the fear" though we know it's there, rather than being fearless or panicked.
(I'm currently working on putting aside the feeling of being sweat-soaked from a half hour midday walk -- by blogging and carefully placed ice cubes.)