I was applying for a position related to personnel work. At the job interview, as expected, the panelists asked me a battery of questions about my work experience and goals. Later on, however, they asked me to demonstrate my "social" skills or talent by singing a song, which I did. Is this part of assessing my personality or is this a sign that they're not taking my application seriously?
They wanted to see how you react under pressure and on your feet. You don't say what the job is but I imagine it's probably something where you're speaking with members of the public and believe me, they will ask you very random questions.
I once attended an interview for a well known toy store and everyone there was given a random toy and told to sell it. Some people just sat in their chair and basically read off the box, some others stood up and pretended they were on one of those television shopping channels and the rest (me included) did somewhere in the middle. Not one person who stayed sitting and reading got the job.
I don't use tactics like that unless I am interviewing for a high visibility, high stress position.
When I do, the purpose is to see how you behave under stress. For one candidate, I asked him a series of obscure questions that nobody should be able to answer. He couldn't answer one correctly, but he did say that he would look it up, or ask someone. This was for a position where his work would show up in a major newspaper. I didn't want a know-it-all, I wanted someone who would stop and check when he wasn't sure. This was a big deal because any mistakes would have been seen by millions.
If the position you are in isn't high visibility, or high risk, this is still not the employer thinking any less of you, but instead bad management decisions where someone heard about a new thing this group that a friend of a friend tried...
Soooo, no it doesn't mean that they're not taking you seriously, but it could be a red flag for bad management if the position you are applying for isn't one where stress and high pressure situations are the norm.
They may be taking it seriously but not know how to conduct a good interview, or they may be looking for how you react to surprise and stress.(Or both.) They almost certainly are not just amusing themselves at your expense. Personally, I would either shrug and comply, then ask why the request was made ... or ask them why first and discuss from there.
When you say "personnel work" I'm assuming you'd be working for HR. HR positions in a lot of organizations will include some aspects of leading "company mandated fun". If HR for this organization is the driver for wacky, moral building exercises or some such nonsense then your ability to let loose and be willing to step out of your serious shoes is something that should be determined in the interview.
As an example, recently I heard about one branch of my organization (a fertilizer manufacturer) that involved finger painting in the relaunch of our company values statement. If your role will likely be one that includes getting industrial mechanics to finger paint, the person to fill that role legitimately needs to be someone who is comfortable being goofy.
Lots of different roles will need someone who is relaxed and willing to take social risks. Tasks like this in the interview can weed out those who freeze up at that sort of risk. They serve the same purpose as technical questions in an interview for a technical role.
It's not unheard of that interviewers, especially when interviewing for management positions, put their applicants on the spot, stress them out, try to see how they react under pressure.
One (not very good) way of doing that is by making ridiculous requests.
There's some business purpose to this, or at least the interviewer thinks so.
Some talents are easy to capture in an interview. If you're interviewing to be a drafter, questions about your proficiency in AutoCAD (or a similar product) are quite reasonable and help quantify your ability to do the job. However, some talents (typically so called "soft skills") are much harder to test. Sometimes the interviewer wants to see what's underneath the veneer you put on when you entered the interview.
Frankly, no matter what job you are interviewing for, you're going to be put into positions that put pressure on you. They can't test for those specific scenarios because they simply don't know what they will be. Each person's career pits them against different challenges. Instead they have to test for generic skills. One of the effective approaches for testing these skills is to ask questions that are outside of the "comfort zone," forcing you to dig deep.
One famous question is from Google, asking about the resistance between two points on an infinite grid of 1 ohm resistors. This particular problem was very popular on the internet a while back as people looked for solutions to it. However, the purpose of the question was not to see who could get the right answer. It was to give an opportunity for the interviewer to see how you approached such problems. How did you structure your work? Did you get frustrated? All of these are very hard to quantify, and even harder to bake into one single numerical metric, but a skilled interviewer can glean a remarkable amount of information just by watching you operate in such a stressful environment.
As for the task seeming to be "unrelated" to what you are interviewing for, it might indeed be unrelated. However, you may be surprised at how interrelated soft skills can be. As you work the job (assuming you get hired), you may learn to appreciate why that particular test was related.
In an interview with an ex-Blue Man Group actor, I came across a similar interview test for clowns. The test was simple. The clown walked on stage in front of a group of people, said nothing, did nothing. They stood there. When they felt they had made meaningful contact with at least one person, they walked off stage. Given that clowns are almost never just standing still like that, the test might seem unrelated. However, if you dig deeper into the job and understand what a clown actually has to do to accomplish their job, that particular test was surprisingly relevant. Also, if you asked anyone to quantify the results of that test, they would chuckle at you and say "that's not how it works, pal."
You can approach such a question may ways. You can jump into it with both feet, and belt out your best Sinatra, or maybe some Go Go's. Or decide not to let the question touch you at all and instead choose a nice rousing round of "Row Row Row your boat," while gathering yourself to answer the next question perfectly. Or perhaps you ask for clarification as to why you are being asked to sing. The ability to politely ask for clarification at the right moments is a highly prized skill in business. It's a skill that can save millions if applied at the correct moment.
Any way you choose to treat it, the purpose of these curveball questions is to get to see a side of you that would not show past the thin veneer we put on when we go to an interview. It's a side that will get out if you get the opportunity to work 9-5 for several years with these people, so they might as well get to know what they're in for! Let them see what you will bring to the table after all those years.
Another possibility is that they could be assessing you as a cultural fit for the company. This is more likely in a smaller company, where fitting in with your team and colleagues is often more of a priority.
I'm not saying that the company is likely to hold regular lunchtime karaoke competitions, but it may be a popular teambuilding activity on work nights out for them, or something similar.
At one company I previously worked at a common interview question they asked was something along the lines of:
"If you were at a company function and you were asked to dance on a table, would you?"
They didn't mind whether the candidate would or would not dance on the table, just that they didn't come across as overly 'corporate' or disapproving. They were looking for a reaction which suggested that the candidate would fit in at company functions and with the rest of the team in general. Their reasoning for asking that specific question was that someone at the company had previously actually danced on a table at a company function!
I can't say whether this is what happened here, but I don't think being asked to sing is necessarily a sign of them not taking your application seriously.
As the previous answers have stated, yes, they're assessing your personality. This is what I've always known as a 'curveball question' where the interviewer tries to shake you up and see how you react.
From my experience they're fairly common (at least in the UK), and I've had anything from "If you were a fruit, what fruit would you be and why?" to "Can you give me 3 uses for a coat hanger other than hanging clothes?"
It's about confidence and how well you can think on your feet a lot of the time.
By the way, I hope you get the job!
At least one interviewing book (I forgot the title) said that attempts to create deliberate stress in an interview result in artificial situations tell little about how an employee will perform in the more sustained stress of much of any real job.
If a company is interviewing for a PR professional, any candidate hired will represent the company in answering numerous appropriate, inappropriate, and "way out in left field" questions, and a stressful surprise is on topic.
However, an immediate stress response (or immediate defensive behavior) says surprisingly little of how most individual contributor (or management) employees respond to typical office stress. Behavioral questions are considered on-topic by a great many organizations; in general, however, most such organizations have shifted away from artificially adding stress to a job interview in order to gather more valuable understanding.
My guess is that the OP is not in PR or another field where employees are expected to field bizarre and possibly inappropriate questions on their feet.