I looked into the issue from statistical point of view. I would have to go with much higher than baseline probability of them being sociopaths on the basis of Bayesian reasoning starting with baseline probability (about 1%) as a prior and then updating on the criteria of things that sociopaths can not easily fake (such as e.g. previously inventing something that works).
Ultimately, the easy way to spot a sociopath is to look for the massive dis-balance of the observable signals towards those that sociopaths can easily fake. You don't need to be smarter than sociopath to identify the sociopath. The spam filter is pretty good at filtering out the advance fee fraud and letting business correspondence through.
You just need to act like statistical prediction rule on a set of criteria, without allowing for verbal excuses of any kind, no matter how logical they sound. For instance the leaders of genuine research institutions are not HS dropouts; the leaders of cults are; you can find the ratio and build evidential Bayesian rule, with which you can use 'is HS dropout' evidence to adjust your probabilities.
The beauty of this method is that it is too expensive for sociopaths to fake honest signals - such as for example having spent years to make and perfect some invention that has improved lives of people, you can't send this signal without doing immense lot of work - and so even as they are aware of this method there is literally nothing they can do about it, nor do they want to do anything about it as there are enough people who do not pay attention to certainly honest signals to fakeable signals ratio (gullible people), whom sociopaths can target instead, for a better reward to work ratio.
Ultimately, it boils down to the fact that genuine world saving leader is rather unlikely to have never before invented anything that did demonstrably benefit the mankind, while a sociopath is pretty likely (close to 1) to have never before invented anything that did demonstrably benefit the mankind. You update on this, and ignore verbal excuses, and you have yourself a (nearly)non-exploitable decision mechanism.
As promised, here is the "Q" part of the Less Wrong Video Q&A with Eliezer Yudkowsky.
The Rules
1) One question per comment (to allow voting to carry more information about people's preferences).
2) Try to be as clear and concise as possible. If your question can't be condensed to a few paragraphs, you should probably ask in a separate post. Make sure you have an actual question somewhere in there (you can bold it to make it easier to scan).
3) Eliezer hasn't been subpoenaed. He will simply ignore the questions he doesn't want to answer, even if they somehow received 3^^^3 votes.
4) If you reference certain things that are online in your question, provide a link.
5) This thread will be open to questions and votes for at least 7 days. After that, it is up to Eliezer to decide when the best time to film his answers will be. [Update: Today, November 18, marks the 7th day since this thread was posted. If you haven't already done so, now would be a good time to review the questions and vote for your favorites.]
Suggestions
Don't limit yourself to things that have been mentioned on OB/LW. I expect that this will be the majority of questions, but you shouldn't feel limited to these topics. I've always found that a wide variety of topics makes a Q&A more interesting. If you're uncertain, ask anyway and let the voting sort out the wheat from the chaff.
It's okay to attempt humor (but good luck, it's a tough crowd).
If a discussion breaks out about a question (f.ex. to ask for clarifications) and the original poster decides to modify the question, the top level comment should be updated with the modified question (make it easy to find your question, don't have the latest version buried in a long thread).
Update: Eliezer's video answers to 30 questions from this thread can be found here.