Cal Newport's new proposal for cognitive fitness has something most advice about attention lacks: numbers.

In an August 24 episode of Deep Questions, Newport suggests three key performance indicators for the mind. Reading endurance is the number of minutes you can stay with demanding but understandable nonfiction without switching context. Contemplation control is how long you can keep making progress on a real problem in your head while walking, repeatedly bringing attention back when it wanders. Written persuasiveness asks you to argue for a contested position and judge the quality of the resulting argument.

This is more concrete than resolving to “focus better.” It is also not yet the cognitive equivalent of timing a mile.

Newport gives each test a scale. Five minutes or less of conceptual reading is “brain-rotted”; about 15 minutes is “distractible”; 30 minutes is what he calls a “pre-2012 average”; 75 minutes is “impressive.” For contemplation, his proposed anchors range from less than a minute at the low end to 30 minutes as impressive. The extreme examples are Theodore Roosevelt's famous appetite for books and Nietzsche's long walking sessions while composing thoughts.

Those labels make the tests vivid. They should not be mistaken for population norms. Newport presents the 30-minute and 10-minute “pre-2012 average” levels as estimates, not as values taken from a validated historical dataset.

The third KPI shows the measurement problem even more clearly. There is no stopwatch for persuasiveness. Newport's scale moves from disorganized, emotional argument through reasonable bullet points, then to good-faith prose argument and finally to arguments built powerfully from first principles. Those are intelligible distinctions, but scoring them reliably would require a rubric and probably independent raters. Two people can agree on a mile time much more easily than on whether an essay is “powerful.”

Cognitive performance really can be measured

None of this means the broader idea is silly. Psychologists measure attention, memory, processing speed, reasoning, and many other cognitive performances all the time. The difference is that a useful scientific measure has to be defined tightly enough that we know what changed.

A 2025 randomized crossover experiment gives a good example. Researchers blocked mobile internet on participants' smartphones for two weeks while leaving calls, texts, and desktop internet available. They measured sustained attention with the gradual-onset continuous performance task, or gradCPT, an established test rather than a self-rating.

Sustained attention improved modestly during the intervention. The reported within-person effects were around 0.24 to 0.28 standard deviations in the two intervention sequences. Mental health and subjective well-being also improved.

That study does not validate Newport's reading test. It does show that attention is not too vague to measure and that repeated cognitive performance can change after a behavioral intervention.

For an individual trying to recover the ability to read for long stretches, a stopwatch may be perfectly adequate for a narrower purpose. If the question is “Can I now read this kind of book for longer without reaching for something else?”, the test is close to the capability itself.

The important part is to keep the comparison honest. Twelve minutes with a dense philosophy book in a noisy airport and 35 minutes with an accessible history book at home are not clean evidence of improvement. Use material of similar difficulty, similar conditions, and the same rule for what counts as breaking concentration.

Training the score is easier to defend than training the whole brain

Newport goes further. He argues that people should train the specific KPI, much as runners train mile time, and that pushing these indicators upward should improve cognitive health more generally.

The first half of that argument is straightforward. Practice sustained reading and you may get better at sustained reading. Practice holding a problem in mind during a walk and you may get better at doing that.

The second half runs into one of the oldest problems in cognitive training: transfer.

A large 2019 second-order meta-analysis examined evidence from working-memory training, video games, music, chess, and other cognitive-training programs. It found that near transfer was common. People improved on the trained task or closely related tasks. Far transfer, improvement on substantially different cognitive abilities, was small or absent, and in the authors' bias-adjusted analyses it fell to essentially zero.

That literature does not test Newport's exact exercises, so it cannot tell us that reading endurance has no broader benefits. It does tell us not to smuggle the physical-fitness analogy in as evidence. A faster mile reliably reflects cardiovascular and muscular adaptations with known relationships to broader health. A higher score on one cognitive task does not automatically establish a generally “fitter brain.”

Fortunately, the practical idea survives a narrower interpretation.

If you want to read serious nonfiction for an hour, measure reading endurance and train it. If you want to be able to reason through a problem without external stimulation, test that capacity under repeatable conditions and see whether it improves. Written argument can be tracked too, although it benefits from a stable rubric rather than a dramatic label.

Your own baseline is more defensible than Newport's “pre-2012 average.” A change from 12 minutes to 35 minutes, measured under comparable conditions, is useful evidence about your reading endurance. It does not need to double as a diagnosis of your brain or a claim that unrelated cognitive skills improved along with it.

Sources

Ulix app

Track Analysis

Track Analysis is a lightweight Android logger for recording timestamped observations and exporting them for later analysis. A personal cognitive benchmark belongs in that modest category: a repeated measurement that can answer a specific question, not a diagnostic score.