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Atomic Reps · The Evidence / The widening gapLast reviewed: August 2026Every claim linked
A research publication by Atomic Reps

The Widening Gap. Who AI carries, and who it carries away.

16 sources, every one gradedReviewed semi-annually

The tests went green. Was that you?

Atomic Reps sells a retrieval-practice tool, so we have a stake in this reading. Every claim links to its source, and the caveat rides next to its number.

Key findingsAugust 2026
  • 01In an eye-tracking study of 21 novice programmers, 20 finished the task with AI help. In the same lab's pre-AI study of the same problem, 11 of 31 could not finish, and every one of them knew it. One study, one course, peer-reviewed.
  • 02The split was not the tool. Students with better grades and higher self-efficacy used AI to build code they already intended; strugglers let it carry them, and the authors say they finished with an illusion of competence. Observed, not measured: the study has no learning-outcome test.
  • 03AI added three new ways to get stuck, by the researchers' own names: Interruption (suggestions breaking your train of thought), Mislead (the tool walking you down the wrong path), and Progression (falling behind the course without noticing).
  • 04Teaching the thinking explicitly works. When novices were taught the problem-solving process itself, they did over twice as much self-initiated work and ended with higher self-efficacy (48 students, two camps, CHI 2016).
  • 05Your confidence in an answer is useful and poorly calibrated. Feedback roughly doubled what survived of lucky guesses in one lab study, and confidently-held errors, once corrected, tend to come back within a week. Small samples, none of it on code.
[02] The study

Twenty-one novices, one problem, an eye tracker.

The lab session

Twenty-one students in a first programming course each sat a lab session: one problem, 35 minutes, GitHub Copilot and ChatGPT allowed, an eye tracker recording where they actually looked. The problem was the same one the lab had used in its pre-AI study six years earlier, which is what makes the comparison tight. All but one produced a working program. Times ran from 5 to 35 minutes, averaging 17.1 (standard deviation 8.1).

The class split in two

Under the surface, the class split in two. Eleven students showed no metacognitive difficulties: they read suggestions, kept the ones matching a plan they already had, and ignored the rest. Ten students struggled, and the researchers watched the assistant amplify the struggle rather than fix it: suggestions interrupted half-formed thoughts, plausible completions pulled them onto the wrong problem, and generated code let them advance without understanding what they were advancing through.

The acceptance numbers

The acceptance numbers tell the same story softly. Students with difficulties accepted 34.1% of Copilot suggestions on average against 24.5% for those without, but the spreads overlap heavily and the paper reports no significance test on that gap, so treat it as texture. The sharper observation is what got accepted: three of the fastest finishers sat near 30% acceptance too, and the difference was that everything they took was something they already wanted.

One institution, one problem

Scope before you generalize: 21 novices, one institution, one 35-minute problem, and a course that had used AI tools from day one. This is a study of people still learning to program, watched closely, not a trial on professionals.

Prather, J., Reeves, B., Leinonen, J., MacNeil, S. et al., ICER '24 (peer-reviewed) (2024)Open-access version (arXiv)

[03] The eight difficulties

Five old ways to get stuck. Three the tools added.

The lab's 2018 study named five ways novices get stuck, all of them failures of metacognition: the ability to notice what your own thinking is doing. The 2024 replication found all five still there, and found the AI tools compounding them rather than curing them. The most common was Location, and the paper is blunt about why: generated code gives an illusion of progress, so you feel far along a path you never actually walked.

Three difficulties were new, and all three are specific to the tools. They matter because they are nameable: research on the pre-AI five shows that simply teaching novices these traps exist changes how quickly they climb out of them.

  • Forming

    Building the wrong mental model of the right problem.

  • Dislodging

    Knowing your model is wrong and still not being able to replace it.

  • Assumption

    Perfectly solving a problem nobody asked you to solve.

  • Location

    Skipping steps early, then feeling nearly done while a loop or a data structure is still missing.

  • Achievement

    Patching a solution that needs a restart, because it feels almost finished.

  • ProgressionNew with AI

    Falling behind the course without noticing, because generated code keeps working above your level.

  • InterruptionNew with AI

    Losing a half-formed thought every time a suggestion appears.

  • MisleadNew with AI

    Following the tool down a confidently wrong path.

Plain-English glosses; the papers' exact definitions are in the linked sources. The five older difficulties come from the same lab's pre-AI study; the three new ones were identified in the 2024 sessions.

[04] The illusion

Failure used to be legible. Now the checkmark is green either way.

The comparison that matters

Here is the comparison that makes this paper worth a page. In the 2018 study, without AI, 11 of 31 students could not finish the problem in 35 minutes. Every one of them knew it. They walked out with an accurate, if discouraging, picture of where they stood.

With AI, six years later

In 2024, with AI, 10 of 21 students struggled with the same problem, and 9 of those 10 reached a working solution anyway, by leaning on the tools. The researchers, watching their words and actions, judge that most of them would not have gotten there alone, and that most finished believing they understood more than they did. The abstract's phrase is 'an illusion of competence'; the conclusion says students already poised to succeed used GenAI to accelerate while struggling students were left with that illusion.

What it does and does not show

Hold the claim to its actual size. This is a comparison across two cohorts six years apart, not a randomized contrast, and the study measured no learning outcome; the illusion is an interpretation of think-aloud and eye-tracking data, which the paper itself concedes. What it documents cleanly is the disappearance of a signal: failure used to be legible to the person failing. Now the checkmark is green either way.

The missing step, named

A 2026 comment in npj Artificial Intelligence gives that missing step a name: AI outputs are results, and they become responses only when a person evaluates them and takes responsibility for them (the authors call it the 3R principle). A framing piece with no data, but a precise one.

Fig. 01 - the signal that disappearedstudents who did not finish · same problem, same lab

2018, no AI · N=31

11 of 31 could not finish

and every one of them knew it

2024, with AI · N=21

1 of 21 could not finish

but 10 struggled, and 9 of those 10 reached working code the researchers judge they could not have produced alone

Counts transcribed from Prather et al. 2018 as reported in Prather et al., ICER '24 section 5.2 (arXiv 2405.17739), and from the 2024 paper's own results. Two cohorts six years apart, not a randomized comparison; the 2024 paper measured no learning outcome, so 'could not have produced alone' is the researchers' observational judgment, stated as such in the paper.

Students who are already poised to succeed can leverage GenAI to accelerate, while struggling students may be hindered by using GenAI, leaving them with an illusion of competence.

Prather et al., ICER '24, conclusions

Rossi, S., Fraccaro, V. & Manzotti, R., npj Artificial Intelligence 2:15 (comment) (2026)

[05] Who splits, and why

The tool did not create the gap. It compounds it.

What predicts the split

What predicts which side of the split a student lands on? In the 2024 study, course grade correlated negatively with the new AI-era difficulties (r = -.503, p = .020), and students who took longer showed more difficulties (r = .693) and lower grades (r = -.727). At 21 students these are directions, not magnitudes: the confidence interval on that first correlation runs roughly -0.77 to -0.08, and the paper reports no correction for running many correlations at once.

The companion study

A companion study by an overlapping team puts the same shape on different instruments. Across a semester of an introductory course (54 enrolled, 40 analyzed), students with higher self-efficacy, lower fear of failure, or higher prior grades used AI less, and later in the problem-solving process. Heavier, earlier AI use went with lower programming self-efficacy (on a 1-to-7 scale) and higher fear of failure (on a 1-to-5 scale).

Two things keep this honest: the authors explicitly refuse the causal reading, since the traits that predict AI use also predict grades on their own, and self-regulation showed no relationship with AI use at all, a null that most summaries of this paper quietly drop. The authors' own headline is the optimistic one: at least some students use GenAI to support, not replace, their thinking.

Negative expertise

The skill the accelerating students had is worth naming, and the paper reaches back to 1994 for the name. Marvin Minsky argued that expertise is substantially negative: knowing what not to do, what not to accept, what not to think. An expert has seen more bad ideas than a novice has seen ideas. Reading a suggestion and recognizing it as wrong in two seconds is negative expertise applied to code review, and it is precisely the asset a novice has not accumulated yet. The tool prices it in anyway.

Margulieux, L. E., Prather, J., Reeves, B. N. et al., ITiCSE 2024 (2024)Minsky, M., International Journal of Expert Systems 7(1) (1994)

[06] Teaching the thinking

Metacognition is not a trait. It is teachable.

The cleanest demonstration

None of this would matter for a practice tool if metacognition were fixed. It is not. The cleanest demonstration predates the AI era: two 2-week coding camps, 48 high-school students, one camp taught web development plus an explicit model of the problem-solving process itself (what stage you are in, how to notice being stuck, how to ask for help about your strategy rather than your syntax), the other taught the same material without it.

What changed

The camps completed the same amount of assigned work. The difference showed up in what happened next: 44% of the taught-the-process campers went beyond the assignment and built more, against 17% of the control camp, over twice the self-initiated work (p = .033). The control camp's productivity tracked how often they called for help; the experimental camp's did not, which the authors read as independence. And self-efficacy, equal at the start, ended significantly higher in the experimental camp (p = .0005).

Scope

High schoolers at summer camps, web development, and the two camps were filled by program registration rather than researcher randomization, a confound the paper names itself. What it licenses is modest and useful: awareness of your own problem-solving process is teachable, and teaching it changes behavior. That is the mechanism every intervention in this literature leans on, ours included.

The wider lens

A CHI 2024 framework paper from Microsoft Research supplies the wider lens: working with generative AI is itself metacognitively expensive. Prompting, evaluating output, and deciding how much to trust it are monitoring-and-control acts, and a tool that raises those demands without supporting them is a usability problem. Cite it for the lens, not for an effect size; it is a position paper.

Loksa, D., Ko, A. J., Jernigan, W. et al., CHI '16 (2016)Tankelevitch, L., Kewenig, V., Simkute, A. et al., CHI '24 (framework paper) (2024)

[07] The confidence vote

Knew it, got lucky, not sure: the evidence under the vote.

The vote

After every Atomic Reps question, you can say how your answer felt: knew it, got lucky, or not sure. This section is the evidence under that vote, graded as hard as the rest of the page, because the honest version includes a hole.

What confidence gets wrong

Learners' feel for what they know is informative and poorly calibrated: in the lab, retrieval practice with feedback left learners almost perfectly calibrated on a later test, while learners without feedback were overconfident.

The practical detail sits in the lucky guesses: answers that were correct but rated as guesses mostly evaporated without feedback, and mostly survived with it. In the one study that measured exactly this, feedback roughly doubled what remained of low-confidence correct answers. That is the 'got lucky' button doing its job: it tells the explanation where to work. Thirty people, general-knowledge facts, one lab.

The strange fact about confident errors

Across many lab studies, errors made with high confidence are more likely to be fixed after feedback than errors made with low confidence, the opposite of what interference theories predicted; the effect is well replicated at short delays.

Two boundaries matter. High-confidence errors are rare, the review says so plainly, so this effect can only ever do a small share of a scheduler's work. And the fix decays: in a week-delay study, corrections fell from .86 of errors to .56, and the errors most likely to resurface were precisely the confident ones. A corrected error is not a closed file. It is the strongest argument in this literature for re-serving an item instead of retiring it.

The hole, stated plainly

Nobody has run the study our vote most directly implies: does adding a confidence rating after a retrieval attempt, with feedback held constant, improve delayed retention in adults on technical material? The adjacent evidence is mixed. Prompting judgments during study averages out to no effect in a meta-analysis. The largest realistic test of confidence prompts, on school assessments, found solid Bayesian evidence for no effect on concurrent scores.

What survives is the narrower claim above: the vote is information routing, not magic. It tells feedback where to work, and one more thing the literature does support: self-assessments are most accurate when made right after a real attempt, in the same format as the real test, which is exactly where ours sits.

Fig. 02 - feedback decides what a lucky guess is worthproportion still correct on the final test
Lucky guess, with feedbackcorrect answer rated 'guess'
85%
Lucky guess, no feedbacksame rating, nothing shown
40%
Error, with feedbackcorrected on final test
82%
Error, no feedbackself-corrected
3%

Effect sizes on this page: Cohen's d measures a gap in standard deviations (0.2 small, 0.5 medium, 0.8 large). Redrawn from Butler, Karpicke & Roediger 2008, Experiment 1 (N=30, 40 multiple-choice general-knowledge questions, 4-point confidence scale, final test after a 5-minute filler): initially correct answers rated 'guess' stayed correct at .85 with feedback vs .40 without; initial errors were corrected at .82 with feedback vs .03 without (d = 6.08). The paper's own summary: 'The function of feedback is to correct both memory errors and metacognitive errors.' Both conditions rated confidence, so this measures what feedback does, not what the rating does. General-knowledge facts, not code.

Butterfield, B. & Metcalfe, J., J. Experimental Psychology: LMC 27(6) (2001)Metcalfe, J., Annual Review of Psychology 68 (2017)Butler, A. C., Karpicke, J. D. & Roediger, H. L., J. Experimental Psychology: LMC 34(4) (2008)Butler, A. C., Fazio, L. K. & Marsh, E. J., Psychonomic Bulletin & Review 18(6) (2011)

[08] Methods

Every paper, graded.

The grade column is ours. It says how much weight the design can carry, not whether we like the result.

Every paper reviewed, with its sample, its design and our grade.
PaperNDesignTaskGrade
Prather et al. 202421Lab observation + eye trackingCS1 problem with Copilot + ChatGPTPeer-reviewed; no outcome measure
Prather et al. 201831Think-aloud studySame CS1 problem, pre-AIPeer-reviewed; closed access
Loksa et al. 201648 (25 + 23)Controlled camps, not randomizedTeaching the problem-solving processPeer-reviewed (CHI)
Margulieux et al. 202440 analyzedSemester correlational studySelf-reported AI use vs traitsPeer-reviewed; correlational
Tankelevitch et al. 2024n/aFramework paperMetacognitive demands of GenAIPeer-reviewed (CHI); no data
Minsky 1994n/aConceptual essayNegative expertiseConcept, not evidence
Butterfield & Metcalfe 2001not obtainedLab, retest after feedbackGeneral-knowledge errorsPeer-reviewed; paywalled, qualitative here
Butler, Karpicke & Roediger 200830 per experimentLab experimentsFeedback x confidencePeer-reviewed, small N
Butler, Fazio & Marsh 201150Lab, 6-min vs 1-week retestError correction decayPeer-reviewed, small N
Metcalfe 2017reviewAnnual Review chapterLearning from errorsPeer-reviewed review
Double, Birney & Walker 2018meta-analysisMeta-analysis of JOL reactivityDoes judging learning change it?Peer-reviewed; read at abstract level
Zheng et al. 2024795 children3-year longitudinal, class-assignedConfidence ratings on school testsPeer-reviewed; Bayesian null
Dunlosky & Rawson 2012not obtained2 lab studiesJudgment accuracy vs retentionPeer-reviewed; direction only here
Rivers 2021reviewSystematic reviewMetacognition about practice testingPeer-reviewed review
[09] Limits

Where this page is weakest.

  • The headline study measured no learning outcome.

    The illusion of competence is the researchers' interpretation of think-aloud and eye-tracking data from 21 students, and the paper concedes it. The controlled outcome evidence lives in the Anthropic RCT on the cognitive-debt leaf; the two are complementary, not interchangeable.

  • The before-and-after comparison is not randomized.

    The 11-of-31 versus 9-of-10 contrast spans two cohorts six years apart at one institution. It documents a disappeared signal, not an effect size.

  • The correlations are n = 21 and uncorrected.

    Directions are defensible; magnitudes are not. The confidence interval on the grade-by-new-difficulties correlation is wide enough to span trivial to strong.

  • The acceptance-rate gap was never significance-tested.

    34.1% vs 24.5% is a difference in means over 10 and 11 students with heavily overlapping spreads, and the paper itself argues acceptance rate is a poor proxy for productive use.

  • These are novices, and we sell to professionals.

    The population is first-course students. The professional analogue is the usage-pattern split in the Anthropic trial, which points the same way, and neither has been run on working engineers over months.

  • The teaching evidence has a registration confound.

    Loksa's camps were filled by program registration, not researcher randomization, and one camp ran mornings while the other ran afternoons. The paper names the confound; so do we.

  • The confidence-vote literature has a hole where our feature sits.

    No study tests whether a post-answer confidence rating, feedback held constant, improves delayed retention in adults on technical material. We ship the vote as feedback routing, and this page says exactly that rather than implying more.

  • The founding hypercorrection paper is paywalled.

    We could not obtain the 2001 full text, so this page carries its finding qualitatively, with numbers only from the replications we could read. Someone with journal access should add the originals.

What we built on this finding

The split in this literature is between people who watch answers appear and people who interrogate them. A daily rep forces the interrogation: you commit to an answer, then vote on how it felt (knew it, got lucky, not sure), and the explanation lands where your calibration was off. Lucky guesses get their feedback; confident misses come back sooner. The hole in the vote evidence is disclosed above, because a page like this is worthless if it only discloses other people's holes.

Read the full case on the evidence hub
[10] Sources

The receipts.

The letter

One study at a time, from issue one.

The Retrieval is this page in instalments: one study worth knowing about, one idea worth a name, and one question you answer from memory in about thirty seconds. Everyone starts at issue one, so nothing in it assumes you read the last one.

Read issue one

An email address. Unsubscribe from any issue.