Sander van der Linden

Who they are

His programme extends inoculation theory past its original restriction to never-challenged beliefs, on the argument that incubation periods vary and people are at different stages of exposure, which licenses prophylactic intervention across a population. That extension is the book's real theoretical contribution.

Its honest corollary, which the book supplies itself, is that in real life you cannot know anybody's infection status, which makes the extension harder to operationalise than it is to state.

Our reliability audit of Foolproof records several things the book does better than its genre usually manages. It prints its own null results. It reports effect-size decay. And it is correct and careful about the backfire effect, treating it as much rarer than was once believed and confining the familiarity version to hedged language, which matches the current state of the literature.

The audit also records what is not in it. The distinction between a shift in response bias and a gain in discrimination is the central methodological question in this area and does not appear, and no critic of the programme is named across the book's source notes. The audit notes separately that the research group has since published work adding a feedback exercise to the games, whose abstract identifies an inadvertent effect on evaluation of real news as the thing being addressed. That paper has not been read here.

Key papers

van der Linden, S. (2023). Foolproof. Read in full in this vault, 26 September 2026, with a reliability audit.

Key ideas

Prophylactic against therapeutic inoculation, and the operational problem that follows from it. See Inoculation Theory.

Gamified delivery at scale, which is a genuine advance in reach over a leaflet whatever the measurement dispute concludes.

Candour about one's own results and candour about one's field are different virtues, and our audit records the book as having the first.

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