Beki Grinter

An Update from My Scales: Why I Won’t Tweet My Weight and Persuasive Computing

In empirical, HCI, research, social media on August 3, 2011 at 9:59 am

I’ve just read the fabulous Fit4Life paper from this year’s CHI, which presents a fictional system called Fit4Life designed following Persuasive Computing and then uses it to critically reflect on persuasion in design. I think it’s important to say from the outset that one fairly common critique of Persuasive Computing is that the interaction is typically framed as being between a tool and the user it is trying to persuade. But, when you use terms like tool so the agency embedded in the machine gets divorced from the person who put it there. It’s designed in.

And now I have a real example.

I recently purchased a wi-fi scale. I like technology and this scale not only computes my weight, but also my BMI and the amount of fat versus muscle I have and then sends that information to a web app (it also has an iPhone and iPad app). Each morning I step on and learn my fate. I believe that scales can compute weight relatively accurately. I think I even understand how BMI is computed, although I note that on webpages that describe BMI they also describe other variables and uncertainties with the measure. My scale does not come with range. It’s definitive. It’s also definitive about my fat and lean ratios. I have no idea how those are computed, how accurate they are, and what variability may exist in making these computations.

On the web I can review my data. And there someone has made some fascinating design decisions. First, I can chose to tweet my weight. It will be a cold day in hell the first time I decide to do that. What were the designers thinking? Then I wondered whether it was meant as social encouragement. I’ve noticed people’s FitBits letting the Facebook world know of their step activity for the week. Is the idea that I could get encouragement from others if I posted my weight? What would I do on days it went up (immediately tweet that it’s due to muscle gain, admit that the Carbonara was good last night) or just be ashamed? I find myself thinking that step activity is a bit different from weight, there’s a relationship but also an ambiguity. I also understand that WeightWatchers groups share their weights for good or bad. But that’s among a group who are sharing together, and that seems different than simply broadcasting it on Twitter.

Second, visualizations of weight and the fat-lean ratios also come with ideals or “objectives”. It tells you how much you have to lose and gain in order to be ideal. Since I don’t understand how my fat-lean ratios were computed, or how the fat, lean and weight ideals were computed, or what the variables not taken into account might be, I’m left with a message about my body that consists of three numbers. There’s nothing I can manipulate except of course my weight (and also my fat and lean within that–and I’m not even quite sure how to manipulate those, strength training, avoiding fatty foods would be my guesses).

These are problems of over-quantification and rationalization of body, of being told by a tool what is wrong or right that doesn’t account for its measures and the weaknesses that they might have, and provides the user relatively little control over their own data. And they are all things discussed by the Fit4Life paper. And thanks to Fit4Life, I’ve been reminded to keep an eye on my responses to my scale. Thanks of course to media pressure, I’m hardly immune to body ideals though.

  1. FWIW, I’ve had fancy digital scales that were grossly inaccurate – 10-15% error or more, even after “calibration”. So I’d question your assumption up there that scales do their job correctly! 🙂

  2. […] to Beki’s blog, I came across the CHI11 article on Fit4life – which I somehow missed before, a nice […]

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