Wednesday 24 April 2024

Jonathan Haidt and Candice Odgers debate the relationship between social media and mental health

Does social media worsen mental health for young people, especially young women? It has become an article of faith for many that it does. And there is bountiful anecdotal and research evidence that supports the view. Take, for example, the furore that erupted back in 2021 around Frances Haugen's leaking of internal Facebook research showing the negative impacts of Instagram on young women.

I've written on this topic several times before (most recently here, but see the list of links at the bottom of this post as well). My take is that much of the research on social media and mental health, or social media and subjective wellbeing, shows correlation, but not causation. The challenge here is that perhaps people with mental health issues (or people with lower wellbeing) are more likely to use online social networks, in which case there is reverse causality (the causality runs from mental health to social media, not from social media to mental health).

So, I was interested to read this recent article in Nature by Candice Odgers, reviewing the new Jonathan Haidt book The Anxious Generation (which I have yet to read, but it is currently on my Amazon Wish List). Odgers really takes Haidt to task, claiming that all that Haidt is demonstrating is correlation, not causation:

The plots presented throughout this book will be useful in teaching my students the fundamentals of causal inference, and how to avoid making up stories by simply looking at trend lines.

Hundreds of researchers, myself included, have searched for the kind of large effects suggested by Haidt. Our efforts have produced a mix of no, small and mixed associations. Most data are correlative. When associations over time are found, they suggest not that social-media use predicts or causes depression, but that young people who already have mental-health problems use such platforms more often or in different ways from their healthy peers...

Odgers then suggests some alternative explanations:

There are, unfortunately, no simple answers. The onset and development of mental disorders, such as anxiety and depression, are driven by a complex set of genetic and environmental factors. Suicide rates among people in most age groups have been increasing steadily for the past 20 years in the United States. Researchers cite access to guns, exposure to violence, structural discrimination and racism, sexism and sexual abuse, the opioid epidemic, economic hardship and social isolation as leading contributors...

The current generation of adolescents was raised in the aftermath of the great recession of 2008. Haidt suggests that the resulting deprivation cannot be a factor, because unemployment has gone down. But analyses of the differential impacts of economic shocks have shown that families in the bottom 20% of the income distribution continue to experience harm... 

Haidt responded, initially on X, but then in thorough detail in this post on After Babel. He starts by pointing to the range of published evidence:

Zach Rausch, Jean Twenge, and I began to collect all the studies we could find in 2019, and we organized them by type: correlational, longitudinal, and experimental. We put all of our work online in Google Docs that are open to other researchers for comment and critique. You can find all of our “collaborative review” documents at AnxiousGeneration.com/reviews

The main document that collects studies on social media is here:
Social Media and Mental Health: A Collaborative Review

Then notes that:

In that document, we list dozens of correlational and longitudinal studies...

In that document, we also list 22 experimental studies, 16 of which found significant evidence of harm (or of benefits from getting off of social media for long enough to get past withdrawal symptoms)...

In that document, we also list nine quasi-experiments or natural experiments (as when high-speed internet arrives in different parts of a country at different times), eight of which found evidence of harm to mental health, especially for girls and women...

I am not saying that academic debates are settled by counting up the number of studies on each side, but bringing so many studies together in one place gives us an overview of the available evidence, and that overview supports three points about problems with the skeptics’ arguments.

First, if the skeptics were right and the null hypothesis were true (i.e., social media does not cause harm to teen mental health), then the published studies would just reflect random noise... and Type I errors (believing something that is false). In that case, we’d see experimental studies producing a wide range of findings, including many that showed benefits to mental health from using social media (or that showed harm to those who go off of social media for a few weeks). Yet there are hardly any such experimental findings. Most experiments find evidence of negative effects; some find no evidence of such effects, and very few show benefits. Also, if the null hypothesis were true, then we’d find some studies where the effects were larger for boys and some that found larger effects for girls. Yet that’s not what we find. When a sex difference is reported, it almost always shows more harm to girls and women. There is a clear and consistent signal running through the experimental studies (as well as the correlational studies), a signal that is not consistent with the null hypothesis.

Haidt supports this with a further footnote:

Yes, there could be a “file drawer problem” if researchers on one side are systematically discouraged from publishing, so the missing “positive” studies are all sitting in file drawers in researchers’ offices. But because findings of benefits would be unusual and newsworthy, I don’t believe that there is a strong or consistent bias against the skeptics. 
However, simply asserting that there is no file drawer problem is not the same as showing that there isn't. That's where meta-analysis comes in. Haidt could easily conduct a meta-analysis with these studies to demonstrate what the overall effect is, and whether there is evidence of publication bias. In fact, he even cites some meta-analyses that have already been conducted (such as this one, which found "mildly significant" publication bias in one of two tests of bias, with the other being statistically insignificant).

Haidt then goes on to address Odgers' suggested alternative explanations, focusing on her assertion that the Global Financial Crisis explains the sudden change in adolescent mental health. Haidt concludes that:

Odgers has pointed to an alternative causal explanation that A) does not fit the timing in the U.S., B) does not fit the social class data in the U.S., and C) does not fit the international scope of the crisis.

Having satisfied himself that he has rebutted Odgers' critique, Haidt then reiterates some solutions from the book:

In contrast, if leaders and change makers were to embrace my account of the “great rewiring of childhood,” in which the phone-based childhood replaced the play-based childhood, what policy implications follow? That we should roll back the phone-based childhood, especially in elementary school and middle school because of the vital importance of protecting kids during early puberty. More specifically, we’d try to implement these four norms as widely as possible: 

  1. No smartphones before high school (as a norm, not a law; parents can just give younger kids flip phones, basic phones, or phone watches).
  2. No social media before 16 (as a norm, but one that would be much more effective if supported by laws such as the proposed update to COPPA, the Kids Online Safety Act, state-level age-appropriate design codes, and new social media bills like the bipartisan Protecting Kids on Social Media Act, or like the state level bills passed in Utah last year and in Florida last month).
  3. Phone-free schools (use phone lockers or Yondr pouches for the whole school day, so that students can pay attention to their teachers and to each other)
  4. More independence, free play, and responsibility in the real world.

Note that these four reforms, taken together, cost almost nothing, have strong bipartisan support, and can be implemented all right now, this year, if we agree to act collectively.

Even if Haidt is wrong about the causal relationship here, I agree that these reforms are relatively low-cost, and the precautionary principle suggests that they might be appropriate. However, I have argued previously that we should be cautious about regulation that allows parents discretion over their children's social media use. Odgers even partially agrees at the end of her review:

Many of Haidt’s solutions for parents, adolescents, educators and big technology firms are reasonable, including stricter content-moderation policies and requiring companies to take user age into account when designing platforms and algorithms. Others, such as age-based restrictions and bans on mobile devices, are unlikely to be effective in practice — or worse, could backfire given what we know about adolescent behaviour.

It will be interesting to see how this debate progresses. Odgers clearly needs to step things up, because Haidt was very well-prepared for her critique, and had clearly anticipated the points that she (and other skeptics) would raise. I look forward to reading the book after I place my next book order.

[HT: Marginal Revolution for the Odgers article, and Haidt's initial response on X]

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