Pablo Delgado
Pablo Delgado is a researcher in reading and educational psychology and the first author of the meta-analysis that settled, as far as anything in this argument is settled, whether people understand less of what they read on a screen. Delgado, Vargas, Ackerman and Salmerón (2018) pooled 54 studies and 171,055 participants and found a small advantage for paper, g = -0.21. The number is real and it has held. It is also much narrower than the way it is usually quoted, because the advantage appears for expository text read under time pressure and does not appear for narrative at all. On this site it is the strongest surviving evidence in the whole screen-time literature, and the clearest example of how much a finding shrinks when you read past the title.
Who they are
Delgado's work sits in the part of the field that asks not whether screens are bad but under exactly which conditions a measurable difference shows up. The 2018 meta-analysis, published in Educational Research Review, is the definitive statement of that question for reading comprehension.
Three things about it are worth carrying. The first is the size. Hedges's g of -0.21 is a small effect: two large groups of readers, one on paper and one on screen, overlap almost completely, and the paper group scores slightly higher on average. It is not the difference between comprehension and incomprehension. It is a difference you would need a study of thousands of people to see at all, which is precisely why it took a meta-analysis of 171,055 of them to pin down.
The second is the evidence base. Fifty-four studies is a lot, and the result is consistent enough across them that this is one of the few claims in the screen-time argument that can be made without hedging about replication. Where the alarming findings in this area have tended to be single striking experiments that later failed, this is a modest finding built on many studies, which is the shape of result that survives.
The third, and the one that changes what the finding can be used for, is the boundary conditions. The paper advantage shows up for expository text, the kind you read to extract and retain information from, and it shows up when readers are working against the clock. It does not show up for narrative. It is a finding about a particular reading task under a particular constraint, not a general statement about screens and minds. Anyone citing it as evidence that screens are degrading comprehension is citing something the study does not say.
Which makes the paper's own title, "Don't throw away your printed books", worth noticing. It is doing more rhetorical work than the findings underneath it support, in an otherwise careful piece of research: the result is narrow and conditional, and the title is neither. That gap between a paper's headline and its contents is the same mechanism by which most overstated psychology reaches the public, and it is a little bracing to find it in the study that turns out to be the most reliable thing in this literature.
For Nicholas Carr's argument, this meta-analysis is both the best support available and a considerable narrowing of the claim. Screen inferiority is real, it is replicated across more than 170,000 participants, and it is specific. That is a smaller and more useful thing to know than any general assertion about what the internet is doing to us, and it is the version this site uses.
Key papers
Delgado, P., Vargas, C., Ackerman, R., & Salmerón, L. (2018), "Don't throw away your printed books: A meta-analysis on the effects of reading media on reading comprehension," Educational Research Review, 25, 23-38. 54 studies, 171,055 participants, g = -0.21 in favour of paper, with the effect present for expository text under time pressure and absent for narrative.
Key ideas
Screen inferiority in reading comprehension is real and small: g = -0.21 across 54 studies and 171,055 participants.
The effect is bounded. Expository text, under time pressure, and not narrative. The boundary conditions are the finding, not a footnote to it.
A well-evidenced small effect is worth more than a striking single result, and this literature is the case in point.
A paper's title is not its finding. "Don't throw away your printed books" claims considerably more than the data behind it.
Concepts on this site
Find them elsewhere
The Seville PRISMA bibliometrics profile lists that Scholar ID among his researcher identifiers alongside his ORCID. No social accounts could be confirmed
Checked 2026-09-10. Handles and affiliations go out of date, so treat this block as a snapshot rather than a standing fact.
Sources
- Delgado, P., Vargas, C., Ackerman, R., & Salmerón, L. (2018), "Don't throw away your printed books: A meta-analysis on the effects of reading media on reading comprehension," Educational Research Review, 25, 23-38.
- Carr, N. (2010), The Shallows: What the Internet Is Doing to Our Brains, W. W. Norton. Tenth-anniversary edition with new afterword, 2020.