There’s a reason that the quantified self movement is doing so well and is getting so much attention. In fact, I think there are two reasons. One is the Observer Effect and the other is the Hawthorne Effect.

The Observer Effect is a phenomenon in science that explains how, by measuring something, you are also always affecting it. One example is measuring temperature. The thermometer you are using has its own temperature. By placing it into a liquid you are both measuring and also affecting the temperature of the liquid. Another example is measuring the air pressure in a tire. It is very difficult to measure the pressure without letting some air escape, thereby altering the pressure of the tire.

This effect clearly plays a role with the quantified self. By recording your steps, photographing your food or using an app to track your push-ups, you measure, but also affect, your routine. Seeing the data influences your behavior and that cycle makes it more compelling to do it.

The social component of sharing this data invokes the Hawthorne Effect. This is the phenomenon that explains how people perform better, work harder or change their habits more frequently when they feel that they are being observed. Sharing your running record on Facebook means your social circle is watching you, and that makes you want to do even better.

I’ve used a bunch of apps to feel better, get stronger or be healthier. I use an app to work on my six-pack (not there yet), another one to train my legs and arms, a running app and a sleeping (and wake-up) app. I also regularly check my heart rate, and keep note of my weight, fat percentage and body mass index with WiFi-connected scales.

This routine developed only after I cleaned up my app collection. A few months ago, I was keeping track of almost everything I did: I kept a log of what I ate, and I wore a Nike FuelBand. Over time, however, I came to realize that even casually tracking stuff takes time. And that time is only worth investing when there is some upside, or conclusion, that you can draw on from the data you collect. I’d like to have a flat stomach, so using an app designed to do that makes sense. I also want to sleep well and wake up rested and relaxed, Sleep Cycle helps me there. It’s the apps that track things but don’t help me reach clear goals that I’ve tended to discard over time, once the cool factor has worn off, of course.

This issue of TNW Magazine focusses on personal fitness and the quantified self. Just by reading these articles you will get fitter, leaner, stronger and healthier. It’s certified. We confirmed that by testing a draft of the issue on 32 volunteers from a range of diverse backgrounds. Whether the positive effects of reading this magazine were attributable to the Hawthorne effect, cognitive bias, or simply because the results were faked, remains to be seen.

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