SWITCH THE LIGHTS OFF! (A practical lesson in normative messaging)

No this is not about Earth Hour, but rather a practical experience I recently had with some unconscious normative messaging and behaviour.

Recently I had a friend visiting from  Brazil staying in our apartment for 2 weeks. One of the first I noticed is that she never switched the lights off when leaving a room.  I decided not to say anything and see what happened. 3 days later she was religiously switching lights off every time she left a room. She had realised switching lights off was the 'normal' behaviour in our household and so had normalised her own behaviour. It struck me this was a perfect example of how simply and easily the behaviours of a lifetime can be changed, just by changing an individuals perception of what is normal. 

I'm hoping she took the new behaviour back to Brazil, starting a viral effect.