I usually ask "What are you interested in?" and just let them speak, then ask them to elaborate a few times. People who find this frustrating are usually low-openness, as are people who become noticeably indignant after being asked to share more.
Also, I ask what are the most important things they are looking for in the team they will be joining. Some people are interviewing because they dislike their current job so this is a good clue about their morale and what kinds of situations can lead them to give up and start interviewing.
By this point, after talking to someone for a few minutes I usually have a sense of whether they are easy to talk to or whether the conversation was draining for me and a notion of how smart I think they are. If both of those feel good I focus on selling the team and what it offers so they bring their A game to the in person interview.
> I usually ask "What are you interested in?" and just let them speak
I've tried that a few times but never really got any decent results out of it. (Disclosure: I conduct ~100 interviews a year.)
The question is too open-ended, so IMO it's akin to asking a child "what did you do at school today?". The answers for that are just non-specific and often the candidate falls back to describing what they currently do at their work. Hell, if they are interviewing for a new job, they are looking for a CHANGE, and I learned just one thing they probably don't like. Instead in preparation I go over the candidate's CV and try to gauge what kinds of technologies, environments and problems they have been exposed to. And then I pick the most interesting and/or longest ones as items of discussion.
Most of the times I find that the candidates are happy to tell about their experiences and voice their opinions. This has the dual benefit of allowing the candidates to better relax, and gives me a glimpse into what kinds of details catch their eye. The very best experiences are those where the candidate forgets they are in an interview and end up treating me to a wonderful lecture on a topic that I have not known enough about. When that happens, I always feel cherished.
The reason why it's a problem is because when a coworker is always in his or her own little bubble and you know nothing about them it is harder to get along with them and thus harder to work with them. And by the same token, if you like and get along with the people in your environment, then you'll be happier and thus more productive.
I don't believe in this at all. Some of the most effective people I've worked with were people that quietly worked in their own space for 4 hrs before lunch and 4 hrs after lunch. Some of them socialized with coworkers after hours, some didn't. At least in engineering field I don't believe it is important to be that open with people unless maybe you're in sales and need that social vibe all day to keep in state. Engineers can be highly effective staying in their own space unless communication is required and omitting the usual everyday small talk BS that wastes 1-3 hours of your day
Sure, those people who keep entirely to themselves may be highly effective programmers. But they will likely not be effective communicators, and unless they are their own manager and work on teams of one, they are going to be less effective overall than someone who can communicate.
This attitude is why so many people bemoan the "frat house / in-group" culture of companies. Why can't you have a pleasant conversation about the problems you are trying to solve at work?
I'll be more specific about openness. It's not bad to be socially introverted. Many of us are somewhat, especially in comparison to the average member of the population.
But imagine you're at a restaurant with your team and someone orders a dish you've never tried. Do you simply decline to try a bite? Or do you try a small bite in case you might like it? I find that openness to new experience correlates highly with good problem solving skills and team cohesion.
Many group/team interactions are essentially minor culture clashes, and being able to navigate them requires being open to different points of view, etc.
Replace dish with drink (or worse, joint). Do you still think people who "decline to try" have a problem? That they should try in case they might like it?
I'm really NOT keen on trying chocolate-cover ants, thank you.
Some people are vegetarians. Others are Muslim or Jewish and only eat halal/kosher foods.
Many groups are discriminated against (historically or presently), and members of those groups may not be too keen to open themselves up to unfair stereotyping. I've dated a girl who would never tell a prospective employer she was Jewish; she just wouldn't eat a pork dish and would probably seem evasive to you.
That doesn't even account for those who may just be squeamish or petrified of insects. Still others have embarrassing dietary restrictions.
It's hard to fathom when you have mainstream traits and limitations (it certainly was for me), but many people who consider themselves others are reluctant to give away information that could later be used to hurt them. Sadly, this reluctance is often justified.
Food is so so so personal and cultural. It's insane to believe someone not eating/not eating a particular food has anything to do with workplace performance.
As metaphors go it's actually pretty good: people often have very specific, very individual, and entirely valid reasons to not eat something. Just as they can have the same for experiences under different conditions. Change the conditions, and you might get entirely different outcomes.
What I'm saying is, the one-shot impressions from interviews are horribly inaccurate. There is simply not enough data, plus the measuring instrument (interviewer) is flawed also in nonreproducible ways.
A simple thought experiment: let's say I build a machine that measures confidence and ability to read the room. Would it select different candidates than you?
I wouldn't. I don't really like food that much. It's easy to ignore when you've had something a million times, but it's harder to ignore when it's a completely new, unpleasant sensation.
But, I understand that other people do like food. And that's ok.
