> Interviewers ask puzzles and give you tricks because they want to see your problem solving process.

It depends on the "problem solving process" you are trying to get insight into.

These procedural "how does the candidate get to the answer?" questions are great for procedural thinkers. Even if they don't know details that feed into reaching an answer, they can show you how they'd get there.

Unfortunately, if your staff ends up entirely composed of procedural thinkers, you may find your company challenged at innovation. For that, you need candidates good at "Eureka" moments.

Your Eureka candidates will often do quite badly in the procedural "what's your thought process?" questions in the one hour interview context. Measured over a 24 hour period, they may do notably better.

"The problem solver initially has a low probability for success because they use inappropriate knowledge as they set unnecessary constraints on the problem. Once the person relaxes his or her constraints, they can bring previously unavailable knowledge into working memory to solve the problem." -- http://en.wikipedia.org/wiki/Eureka_effect#How_people_solve_...

What you're looking for here is both broad and deep domain expertise, coupled with an ability to understand the question well then let the subconscious mind pull together the insights needed for a breakthrough solution. This process cannot be talked through out loud. The answer may take longer (hours, a day or two, probably reached in the proverbial shower), but will often be an answer that gives you a long term competitive edge over a blunt procedural approach.

This said, it's not clear to me how to interview for this ability. I'd start by considering a way to understand the depth and breadth of a candidate's exposure to technology and domain knowledge. This is the opposite of interview processes using dives into the interviewer's area of expertise. I might consider a two part interview a few days apart, where the candidate gets the context in part one, and shares their thinking in part two.

> Asking a candidate a difficult brainteaser that may be even close to impossible can be extremely revealing. There isn't a canned response, you get to see them work under pressure, you experience live problem solving and you can understand how they move through their work better. All of these factors are just as important as competency when hiring.

Except that this situation is an artificial construct. You're covering their mouth and nose and saying, "Now show me how you breathe." You are favoring candidates whose problem solving is informed by the belief they can reach an emergency answer on their own through brute force, rather than those whose problem solving starts with the assumption that someone else has already solved or mostly solved the problem and who is great at finding the "shoulders of giants" to stand on, building an informed answer a priori.

I'm reminded of getting my deep water scuba certification. You're not interviewed for a diving salvage job by repeatedly seeing how you handle having your breathing apparatus turned off. Yes, a diver should be able to "perform under pressure", but what you really want are divers who help ensure nobody on the team ends up under pressure.