IMO as long as the timestamps indicate the lower-information answer as a "fastest gun in the west"-type thing and it is not an unattributed copy-paste, it should be left alone to its own democratic fate by the community (votes) and the questioner (accept).

• If the answer came in more than a few minutes - say 20-30 -- later, to me it shows that the poster more than likely did not read the existing more complete answer or simply ignored it. In that case, I would downvote it with a comment indicating why, and recommending either a self-delete, or a more extensive edit (adding unique information) to cure the downvote.

• As Eliah mentions, there certainly are cases where such later-and-with-less-information answers get upvoted more and sometimes even accepted. I think those should still be left alone, trusting the law of averages and a somewhat intelligent reader who will return to read the alternatives if the accepted/most-upvotes answer doesn't do the job. I would certainly upvote the more informative answer(s) though -- as I usually do anyway -- while not voting on the later-with-less answer.

• For new answerers who might get agitated in the above situation when theirs is the older answer -- as I was a while ago -- here's a reassuring example of democracy in action in a somewhat similar situation. Note that the answer was initially unaccepted, got Populist and then seems to have even convinced the OP to change his mind and switch his accept.

IMO as long as the timestamps indicate the lower-information answer as a "fastest gun in the west"-type thing and it is not an unattributed copy-paste, it should be left alone to its own democratic fate by the community (votes) and the questioner (accept).

• If the answer came in more than a few minutes - say 20-30 -- later, to me it shows that the poster more than likely did not read the existing more complete answer or simply ignored it. In that case, I would downvote it with a comment indicating why, and recommending either a self-delete, or a more extensive edit (adding unique information) to cure the downvote.

• As Eliah mentions, there certainly are cases where such later-and-with-less-information answers get upvoted more and sometimes even accepted. I think those should still be left alone, trusting the law of averages and a somewhat intelligent reader who will return to read the alternatives if the accepted/most-upvotes answer doesn't do the job. I would certainly upvote the more informative answer(s) though -- as I usually do anyway -- while not voting on the later-with-less answer.

• For new answerers who might get agitated in the above situation when theirs is the older answer -- as I was a while ago -- here's a reassuring example of democracy in action in a somewhat similar situation. Note that the answer was initially unaccepted, got Populist and then seems to have even convinced the OP to change his mind and switch his accept.