In the same way, people will notice if they are suddenly thrust into an intolerable situation, and will take steps to change it, but if their situation gradually gets worse, they may not notice and may just put up with it. Habituation is also illustrated by the old story about boiling a frog: if you put a frog into boiling water, it will leap out, but if you put it into comfortably warm water and gradually raise the temperature, it will stay put and allow itself to be boiled alive. Neurotypical peopleвЂ™s brains can adjust to the idea that the stimulus is ongoing and is not new information, and so stop presenting it to the conscious mind but some peopleвЂ™s brains are less able to do that, so they keep noticing the background noise or flashing light, and may become annoyed or fatigued by it more quickly. It is more difficult for people on the autistic spectrum or those with sensory processing difficulties to вЂњtune outвЂќ stimuli such as smells, background noises and flashing lights. (There is an apocryphal story about someone who lived near a clock which loudly chimed the hour, and he slept through the sound of the chimes every night, but one night the 3am chime failed to sound, and he leapt out of bed shouting вЂњWhat was that?вЂќ) If you spend long enough in the smelly building, you might even grow so used to the smell that you think the outside smells strange when you eventually leave! Similarly, many people can become accustomed to background noises such as traffic or ticking clocks, and stop consciously noticing them. For example, you might walk into a building that smells strongly, but after spending some time in the building, you stop noticing the smell. The hedonic treadmill is related to the idea of habituation: that people become accustomed to an ongoing stimulus and stop consciously noticing it. The hedonic treadmill applies to groups of people as well as individuals: research shows that as a countryвЂ™s wealth increases, its citizens do not report any increase in their subjective well-being. Many peopleвЂ™s life paths are characterized by working hard in order to progress in their careers, grow in wealth and prestige, and get a bigger house and a better standard of living and yet their subjective happiness will often remain the same despite these improvements. The вЂњtreadmillвЂќ description refers to the idea of having to keep moving just to stay in the same place. The same Greek word gives us вЂњhedonismвЂќ, the philosophy or lifestyle of pursuing pleasure.

вЂњHedonicвЂќ refers to pleasure or happiness (from the Greek hedone, вЂњpleasureвЂќ). Similarly, people who suffer debilitating accidents go through a period of grieving, but then often return to their original levels.

However, research shows that lottery winners usually experience a temporary boost in happiness and then revert to their original happiness levels.

This is unintuitive, because people tend to think that winning the lottery would make them permanently happier, or becoming severely disabled would make them permanently more miserable. The hedonic treadmill refers to the idea that peopleвЂ™s subjective happiness levels stay around a given set point throughout their life, and are not permanently affected by major positive or negative life events.

Hedonic treadmill