Why interviews are decided in the first 3 seconds, and why you only need a sip of the milk to know if the bottle is off...

Those who have worked with me for any period of time, and by that, I mean more than five minutes, may have heard me use the following phrase:

You only need a sip of the milk to know if the bottle is off.

I like to think I created this phrase, but I didn't. I heard it on Newsround when I was a kid (that was many years ago), when they were interviewing an opinion pollster who was asked why they base their opinion polls on just 100 people. Well, you only need a sip of the milk to know if the bottle is off, he said.

As a digital marketer, I've mostly used this in an analytics context. It takes me roughly 30 seconds inside someone's Google Analytics to know if there's a problem, and that's including the horrendous load time.

Academics have gone far deeper into this than I. Daniel Kahneman wrote Thinking Fast And Slow many years ago, arguing that there are two systems of thought - the instinctive, emotional system, and the longer, more analytical system.

If we're looking at interviews, I've known for many years that most interviews are concluded in the first few seconds on the basis of that first system, and the rest is a dance to ascertain whether that initial instinct was right or wrong.

Is this the best way of interviewing? I'm unsure. I've tried to free myself of that initial instinct and remind myself that I should be rigorous in my vetting process, give the candidate time to position themselves.

And yet we all do it. We meet a candidate for the first time and we know.

It could be their confidence. The handshake, the smile, the easy banter, the "oh yeah, I'd kill for a cup of tea" and then you've got something in common. Tea, maybe. Or you live in the same area. Everything is falling into place.

From this point on, the interview is about confirming your initial instinct. Yep, got the experience. Yep, the banter is the right level. Yep, got the cultural fit. Yep, keen on the job role. At some point, if it's going this well, you switch from interviewing to selling and you're in essence being interviewed.

Or - horrendously - the interview takes a turn and the candidate says something like "I enjoy pulling the heads off sheep and offering them to my Lord Satan" and silence falls. But they had good banter. But they had the skills. It was all going so well. Until they mentioned the sheep / Satan thing. Shame, that. I don't think they'll fit in around here.

Or you could meet a candidate and instinctively think - there's something wrong here. I don't get the vibe. And this is before you've really tested their capabilities.

In many cases, I've been right, but in a fair few cases I've been absolutely wrong. I started off with a bad vibe and the more I sought to confirm that, the more the candidate opened up and proved me wrong. And yet still there's that nagging doubt because of the first three seconds.

There is no right or wrong way here. The milk bottle test is a great barometer, and it's an instinct we can't get away from in recruiting. It's hard to rein in your instincts and make a quick judgement - and it's harder to turn around that initial instinct, which is often the basis of the whole interview.

But it's worth knowing what your mind is doing. It's worth knowing that you've got two systems of thought at play in this interview.

And it's also worth knowing that candidates have exactly the same systems of thought going on in their heads too.