Minds don’t have immune systems, except they do.

Minds do not have immune systems that can be examined under a microscope or described in a medical textbook. But minds can be understood through metaphors and models and at that level, our cognitive system often exhibits attributes and behaviors that are reminiscent of the human immune system.

There are several aspects to “cognitive immunology” with varying degrees of overlap with the medical metaphor.

The closest cognitive analog to an immune system arises in the context of inoculation theory. The idea underlying inoculation is that people can be protected against an “infection” by misinformation (or other questionable types of information) by being presented with a weakened dose of the “virus” to stimulate the creation of “cognitive antibodies”.

In a typical application of inoculation, people are first warned that they might be misled before they are shown a pre-emptive rebuttal of misleading rhetoric that they might encounter in the future. The purpose of the warning is to sharpen people’s attention and make sure they are alert when they encounter information in the future. The purpose of the pre-emptive rebuttal is to defang the impact of subsequent misinformation that follows the same basic structure. And herein lies one of the strengths but also a weakness of inoculation: we need to know ahead of time how people might be misled, so we can pre-emptively rebut that technique, although we do not need to know exactly what it is that people will see.

To illustrate, a common aspect of misinformation is that it is internally contradictory. For example, people who refuse to accept the science of climate change, may on the one hand claim that global temperature cannot be measured accurately while also assuring us that there is nothing to worry about because the world has been cooling for a few years. The obvious problem with this is that one cannot make a claim about cooling (or indeed warming) when the global temperature cannot be measured. The contradiction alone is sufficient to rule out this argument.

I was part of a team led by Jon Roozenbeek of Cambridge University that recently showed in a series of experiments that people are able to learn to detect misinformation from brief videos that explain misleading techniques—such as incoherence—to them. Crucially, the inoculation videos were generic and didn’t have to anticipate any specific content: it was sufficient to know how misleading content might be presented. This basic result has now been replicated many times, and the videos and other inoculation tools can be found on a website of inoculation resources.

Another variant of “cognitive immunology” departs from the strict inoculation metaphor and invokes the notion of “boosting”, perhaps akin to the way in which our general immune system can be strengthened in a number of ways identified by the Centers for Disease Control. The boosting approach rests on the idea that people’s performance in a wide range of tasks and situations can be improved by providing them with clever hints that leverage their ability to acquire or extend their competencies. A collection of helpful boosts and training tools can be found at this website of boosting resources.

There are a number of ways in which boosting can be applied to strengthen people’s cognitive immune system against misinformation. One of those ways involves “critical ignoring” and is a close cousin of the idea of critical thinking. The idea behind critical ignoring, outlined in this article, is that our attentional capacity is limited and that we must choose to ignore much of the information that is out there. We cannot do everything in our newsfeed justice, and so rather than stretching ourselves too thin, we should focus on a few valuable items of information while ignoring much else.

There are at least three types of cognitive strategies for critical ignoring: self-nudging, lateral reading, and the do-not-feed-the-trolls heuristic. Self-nudging might involve us removing temptations from our digital environment. If Instagram is on the last page of apps on your smartphone, you are likely to use it less than if it’s on the home page and just a single tap away. Lateral reading refers to the strategy practiced by fact-checkers to ignore what a website says about itself, but to look elsewhere to assess its credibility. Of course, a website sponsored by the fossil fuel industry will claim to provide “scientific evidence” that climate change is nothing to worry about, but Wikipedia will reveal very quickly what the true agenda of that site is. Finally, the do-not-feed-the-trolls heuristic advises us to avoid rewarding malicious actors with attention. Ignore trolls, block them, and report them to the platform if they are abusive—but do not engage.

Although the competence of critical ignoring is relatively easy to boost once its power is understood, it requires a paradigm shift in our thinking about attention. Paying close attention is often heralded as a hallmark of critical thinking and achievement—and it is, but it must be accompanied by the companion skill of critical ignoring so we can shield ourselves from the excesses, traps, and information disorder of today’s online attention economy.

Minds do not have immune systems one can see under a microscope, but viewing minds through the lens of cognitive immunology can reveal real antidotes to misinformation, disinformation, and information chaos.