In 1999, the United States government filed a truly enormous lawsuit. Their adversaries were nine tobacco companies. Citing a law normally invoked in cases involving the Mafia — the Racketeer Influenced and Corrupt Organisations Act — the government alleged that Big Tobacco had engaged in a giant criminal conspiracy over the entire latter part of the 20th Century. The companies knew, alleged the prosecutors, that smoking was harmful, causing lung cancer among many other diseases — indeed, they’d even proved it, in their own secret research, which dated back to the 1960s. But they had apparently gone to extreme lengths to keep that evidence under wraps, all the while using PR tactics to deliberately confuse the general public about the dangers of smoking.
Has the same thing just happened all over again? In what’s been portrayed as a shock revelation — with lots of accompanying outraged commentary — the Wall Street Journal last week informed its readers that “Facebook Knows that Instagram is Toxic for Teen Girls”. The Journal’s reporters had gotten their hands on some internal research done by Facebook, which owns Instagram. The conclusions, which had been kept private, are pretty scary: being on Instagram is making the site’s younger users begin to worry about how attractive they are, making one fifth of them feel worse about themselves, and exacerbating mental health problems. In the Journal’s exposé, the US Senator Richard Blumenthal and the psychologist Jean Twenge are quoted drawing a direct analogy from Big Tech to Big Tobacco: both have covered up research that their product, aggressively marketed to young people, is causing harm.
But the parallel doesn’t work. The research mentioned in the judge’s decision from the Big Tobacco case — which the nine companies lost in 2006 — was impressively extensive. It included experiments where cigarette tar was painted onto the backs of mice, causing tumours; a study of the effects of smoking during pregnancy on birthweight; studies on rats and rabbits exposed to tobacco smoke who developed tumours, emphysema and a whole panoply of other lung diseases; and studies that varied the strength of cigarettes to see if different “doses” led to different symptoms in humans.
Compare that to what’s in the “Facebook Files” (which, by the way, include leaks about several other topics, like the effect of social media on political debate, democracy, and human trafficking). The only evidence we’ve seen thus far is from surveys — teens filling in questionnaires about the effects they thought Instagram had on their wellbeing and mental health. The Journal also mentions larger studies, which link measurements of time spent on Instagram with survey responses, but no details are provided.
So, it would be as if Big Tobacco had sent a questionnaire to smokers, asking whether or not they’d gotten lung cancer, and whether they thought it was down to their smoking habit. If that was all we had, it would hardly be worth writing home about (or, indeed, in the Wall Street Journal): surveys might be an interesting spark for further research, but they’re a million miles from conclusive evidence.
“Correlation is not causation” is simultaneously the most hackneyed phrase and overlooked rule in science: although everyone’s heard it, people writing about studies — journalists and even the scientists themselves — routinely portray purely correlational or observational research as if it was an experiment testing the effect of one thing on another. This is the source of exciting headlines about how being optimistic makes you live longer, or that being more materialistic makes you depressed, or that drinking diet fizzy drinks makes it harder to lose weight — but no useful insight into the causes of health issues. In the Instagram case, the fundamental problem is that we don’t know whether more time spent on Instagram made the teen’s mental health worse, or — an equally-plausible opposite hypothesis — whether teens with worsening mental health for other reasons tended to spend more time on Instagram.
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