The Madness of Crowds: From “Tulipomania” to the “Anti-Vax Movement”

THE OBJECT OF THE AUTHOR in the following pages has been to collect the most remarkable instances of those moral epidemics which have been excited, sometimes by one cause and sometimes by another, and to show how easily the masses have been led astray, and how imitative and gregarious men are, even in their infatuations and crimes.

Charles Mackay – Memoirs of Extraordinary Popular Delusions and the Madness of the Crowds

Image courtesy of Marcos Vasconcelos (click for original)

I’ve been interested a bit in looking at how to help people find high-quality information on the web – recently, I have been exploring how to help people make better credibility judgments about the information they find. One paper I was reading, “Statement Map: Assisting Information Credibility Analysis by Visualizing Arguments” by Koji Murakami and others at the Nara Institute of Science and Technology in Japan, uses as a motivating example the recent movement against vaccinations for children, specifically the MMR (Measles, Mumps, and Rubella), as the result of fears that these vaccines could cause autism.

Back in 2003, Pew reported that over 80% of Internet users have searched for health information (such as info about fitness or vaccinations) online, and one can imagine that this number has only grown since then, so this example is important in illustrating the potential impact of such health memes. I’ve heard multiple parents mention the supposed vaccination-autism link before when making decisions about whether or not to vaccinate their children, so it’s extremely important to figure out how to make sure these parents get intelligent, credible information when searching on the web. The Murakami paper provides some interesting background information on how this particular meme first started:

In 1997, a group of researchers in the UK lead (sic) by Dr. Andrew Wakefield published a study implying a causal connection between Measles, Mumps, and Rubella (MMR) vaccinations and the development of autism in children. Though further scrutiny of these initial results  disproved the autism-vaccination link – culminating in the withdrawal of endorsements by 10 of the study’s 12 authors – the damage had already been done.

The consequences of this single, spurious, study have already been far-reaching. The resulting backlash precipitated a drop in vaccination rates in the UK (where the study was first published), which has led to an increase in outbreaks of measles over the past decade to the point where measles are once again (after transmission was halted 14 years ago) being considered endemic. Even vaccination rates here in the Bay Area have dropped, with the Examiner reporting that vaccination rates are as low as 50% for some Bay Area schools.

I suppose a lot of this can be chalked up to mainstream media coverage of the original study (as well as coverage of well-meaning, but misguided celebrity activists like Jenny McCarthy). However, a large part of why this meme has continued even after the original study was shown to be dubious is due to social phenomena such as communal reinforcement (or the “millions of people can’t be wrong” phenomenon) that can occur so easily on the web. Because it is so easy to publish information on the web, and because information published tends to persist, it is easy to find a wealth of documents supporting any viewpoint, no matter how much evidence there actually is to support that claim. In this case, one can read 100 different news articles, blog posts, and other online resources based on the Wakefield, et al. study without knowing first that these stories do not corroborate each other (as they are drawn from the same small, possibly falsified study) and second that the original study was actually recently retracted by the journal in the first place.

The way that these stories snowball and take on a life of their own is something that Charles Mackay documented in his book “Extraordinary Popular Delusions and the Madness of the Crowds” (the first lines of which are quoted above). He tackles a variety of subjects ranging from the Dutch tulip craze of the 16th century (cf. “21st century housing bubble“) to alchemy to witch hunts. From this book (written in 1841), we can see that the often reasonable shortcuts that people make when processing new information can sometimes lead to these self-propagating effects which take on a life of their own.

The unfortunate fact is that just because the web gives us access to more information doesn’t guarantee that we are going to choose and use it wisely. This is why building tools to help people make better credibility judgments online is so important, raising two questions:

• How do we extract data from within a single web page to help people make better judgments about the information it contains? I know that there is a good deal of work on this topic in Wikipedia with tools like Wikipedia Scanner and PARC’s WikiDashboard helping to to expose author and change information, but how can we bring tools like these to the web as a whole?
• How do we connect data across web pages to hep propagate changes in information across the web? As an example, if information about the study’s retraction could be propagated to pages reporting on the study, parents reading those pages would be less likely to be led astray, possibly saving lives.

For those who are specifically interested in the MMR vaccine controversy, the Wikipedia page links to a lot of good resources, including a long list of studies conducted in the last decade which show no link between autism and the vaccine.