Imagine a stranger approaches you on the street and demands to either (1) take a sample of your spit so they can sequence your DNA or (2) plug a device into your smartphone that will transfer over to them your last month of sleep and activity data. Which are you more likely to hand over? Which feels less personal, less intimate?

Until recently, I would have assumed that for most people they’d be more reluctant to hand over their DNA sequence. But now I’m thinking it might be the opposite.

I’ll share this but not that

Back in December I talked with someone who developed and runs a website where people can upload genetic and other data for public use. The idea is that making such data publicly available enables researchers and other citizen-scientist types to easily access it and pursue scientific questions such as which genetic variants are associated with which traits and diseases.

Importantly, unlike my hypothetical scenario above, on that website all such data submissions are entirely voluntarily, and in fact the creators even try to actively dissuade people from contributing just to avoid people doing it and regretting it later. Genetic data was originally the focus of the tool, but more recently the developers considered adding the capability for people to upload their FitBit and other self-tracking device data to the site.

Their users and other commentators were generally not enthused about the idea of sharing that type of data. Why is that? Here are some of the developer’s thoughts:

“I think because still like the genotype data is pretty muddly, in terms of what you can learn from it, whereas it’s probably much more interesting how much sleep you are getting every night, how active you are over the day, things like this…people were like yes — sharing your genome I can somehow see but then the sharing, like, your weight, how much you sleep and how much you move over the day, this people found less easy about, I would say.”

Genetic anti-exceptionalism

Wait, your step counter is more precious to you than your “muddly” DNA? This all runs counter to the common phenomenon of “genetic exceptionalism,” where genetic information is held up above other types of personal information as more potent, more powerful, and perhaps in need of more protection. While many have argued this is a misguided position to take, especially when it comes to policy making and personal privacy protections, it is still a pervasive idea. But clearly not so much with the users of the data sharing website discussed above. People who decide to submit their genetic data for all the world to see are reluctant to share so openly data about their sleep, exercise, and nutrition.

What makes data personal?

What’s going on here? What are the criteria by which some information intuitively feels more private to us than others? I think there are at least three contributing factors.

• Visible

Is the data visible to us, or tangible in some way? Even though our genetic sequence is partly responsible for building and maintaining our very visible and tangible bodies, it is a rather abstract concept to most of us. We can’t see or feel our DNA, unless we’ve done that favorite science fair experiment where we mix spit with some dish soap and other household items and watch our snot-like strands of DNA precipitate out of solution.

Sleep and activity, on the other hand, are very tangible, very immediate. We can envision the physical processes of going to bed and going for a walk. There are also specific places we go each day to carry out these activities.

• Relevant

Luckily, for most people, our DNA sequence doesn’t seem to directly impact how we feel or how we move through the world on a daily basis. (I’m thinking in contrast to people with genetic disorders that may affect their movement, diet, cognition, etc.).

For sleep, on the other hand, we can physically feel the results of excesses and deficits. It also has a cadence, a longitudinal pattern, that I think also makes it feel a little more relevant, in contrast to our (mostly static) genome.

• Identifiable

Now this one’s interesting. Because despite what anyone tells you about “de-identified” genetic data, genetics is inherently identifiable. Given two DNA samples from the same person, you can tell with a high degree of certainty it’s the same person (or their identical twin). Granted, I’ve thought more about the identifiability of genetic data than of sleep and activity profiles, but let’s consider those. With sleep patterns, you might not be able to say exactly who someone is. But maybe you could say what type of person they are based on sleep patterns. Things like a morning person vs. night owl would be relatively easy to tease out, as would perhaps parents with young children or someone who works a night shift.

Another potential factor here could be “judginess” of certain data. With all our FitBits and default smart phone activity tracking, there’s certainly some societal pressure to get in your 10,000 steps a day and your 8 hours a night (though some would rather brag about their ability to thrive on only 4 or 5). Would we be similarly judgy about each other’s DNA? Films like GATTACA suggest we would. But if I’ve brought up GATTACA, then it’s clearly time to wrap up this post.

I’m curious to hear your thoughts about what types of personal data feel more private to you? Which would you be more or less likely to share?