My answer to this would be that people have dispositions to behavior, and these dispositions color everything we do. If one might profit by showing courage, a coward will not do as well as a courageous man.
Of course, the relative success of such people at faking in appropriate situations is perhaps an empirical question.
ETA: this makes less sense as a direct response since you edited your comment. However, I think the difference is that “being a cooperator” regards a disposition that is part of the sort of person you are (though I think the above comment uses it more narrowly as a disposition that might only affect this one action), while a precommitment… well, I’m not sure actual people really do have those, if they’re immutable.
My answer to this would be that people have dispositions to behavior, and these dispositions color everything we do. If one might profit by showing courage, a coward will not do as well as a courageous man.
Of course, the relative success of such people at faking in appropriate situations is perhaps an empirical question.
ETA: this makes less sense as a direct response since you edited your comment. However, I think the difference is that “being a cooperator” regards a disposition that is part of the sort of person you are (though I think the above comment uses it more narrowly as a disposition that might only affect this one action), while a precommitment… well, I’m not sure actual people really do have those, if they’re immutable.