If the subtitle (Do orchestras really need someone flapping their arms on a podium?) had fit in the 80-character limit, I would have added it to the title here.

I probably should have titled it something like "What do orchestra conductors do?". So it goes.

Metal has air guitar.

HN readers, please raise your hand if the first thing you though about when reading the headline was not electricity. Now put your hands down if it was something to do with thermal energy. Now put them down if you were thinking about trains. If your hand is still up, please remove all metal items, swallow this, step into the fMRI, and hold still.

I thought buses ... it's very late and I've had a drink, I'm not really that old either but I'd heard that London Transport were thinking of having conductors again, so ...

I looked at the domain. Telegraph? Of course it's about electricity!

So, basically, whoever thought "orchestra conductors" needs an fMRI?

The elements of the joke are as follows. I assumed that HN readers have a higher probability than the general population to associate words with scientific or engineering meanings. I further assumed that as this site has a high association with electronics, the electrical meaning of conductor would be most prevalent. This was reinforced by the parent post, who stated nearly exactly what I had been thinking, right down to the smirking overcleverness with which it described to motion of elecromagnetic charge. Before clicking on the link, I thought of other things that could be meant by "conductor". I came up with heat transfer and train tickets. I didn't even think of orchestras, probably because I had always been in bands, where the leaders were overwhelmingly directors, band leaders, and drum majors.

The second element of the joke is that I presumed that HN readers, having a variety of esoteric hobbies, might also have an interest in cognitive science and linguistics (particularly the AI folks), and might want to analyze the brain of an outlier. I then decided that, while less accessible to a home hobbyist than brain surgery or in-depth psychological profiling, fMRI imaging conveyed the point of the joke in shorter, more recognizable wording, without actually being a very probable outcome.

In reality, you would probably be wired up to a home-made sensor array and presented with a series of time-indexed sensory inputs via headphones and a computer screen, and perhaps asked to press certain button sequences in response.

So, in short, no, those people do not need a fMRI. You, however.... I would like to analyze your physiological response to traditional comedy and contrast that with nerd jokes....