“I wonder if that piano-staircase becomes as irritating to locals (well, you know) as Honda’s ‘musical road’ experiment. It must be quite the cacophony during rush hour – would that have an adverse effect, with people electing to use the escalator to avoid adding to the noise? Are there examples of these (simple?) reward systems backfiring through over-use or abuse?”

Naturally the kids there loved it, and loved using it, but after twenty or so runs through its limited vocabulary in the space of three minutes I was about ready to dedicate the rest of my life to wilful littering as a matter of principle.

Still, it did seem to work. How those unfortunate enough to have to spend a working day within earshot feel about it, I wouldn’t like to guess.

Am very interested in how this type of activity could lead to long-term attitude change and hopefully permanent behaviour change. Especially, as you say, when the fun element is not there anymore.