Leah Gerber

Under what conditions does a particular person become unusually good?

I study the conditions that shape how different people think, create, learn, work and flourish. Not people on average. One person at a time.

The question

Hypothesis The conditions that sharpen one person seem to flatten another. And my own output swings from day to day, under conditions nobody was tracking.

So instead of asking what makes people perform well, I want to ask a smaller and harder question. What makes this particular person perform well?

This is a research notebook. It starts with questions, not answers.

First essay

Same brain, different day.

Draft 01 · being rewritten in public

I’ve spent most of my life trying to understand my weaknesses. I’m starting to think that was the wrong question.

The usual way to think about yourself is as a list of traits. Good at this, bad at that. The list feels permanent, like height or weight. You work on the weaknesses and lean on the strengths. The list stays the list.

But some days I think clearly and some days I can’t. Same brain. Whole weeks go the same way, ideas arriving in a run or not at all. If my abilities are fixed, why does my output swing like that?

Observation Away from the desk and the calendar for a stretch last year, I started noticing when my thinking was good. Ideas showed up in the first hour after waking. After unusually long sleep. On day three of a backpacking trip. Walking through a city I didn’t know. Almost never at a desk, and almost never on command.

For a while I read that as proof I had changed. Now I think something simpler happened. I hadn’t changed. My conditions had.

Hypothesis What a person can do is not one number. It is an interaction between the person, their environment, their state, and the task in front of them. Move any one of those and the output moves. Said plainly it sounds obvious, and I doubt I’m the first to think it. But little in how I was hired, schooled, tested or managed behaved as if it were true.

Every test I have ever taken measured me under conditions someone else chose. The room, the hour, the format, the time limit. So did interviews and performance reviews. Were they measuring ability, or performance under those particular conditions? I can’t stop turning that one over.

The question gets more interesting pointed at one person instead of people in general. Not is she creative, but under what conditions is she more creative than she usually is. Not he’s a strong analyst, but why was his Tuesday so much better than his Monday. The variation I care about is the kind that happens inside one person over time. An average taken across people cannot reach it.

Question For a particular person, what conditions reliably come before their best work? Sleep, movement, solitude, company, novelty, pressure, the absence of pressure. And if those conditions can be found, can they be recreated on purpose?

I’m at the beginning. Whole research fields live near this question. Person-environment fit, within-person variability, N-of-1 trials. I haven’t read enough of them yet to tell you what they’ve found. That is the project. Read the literature, talk to people, run small experiments on myself, and write down what survives. When I know something, I’ll say how I know it. When I’m guessing, I’ll say that too.

Most of these essays will end with a real question, because your answers are the observations I don’t have.

Where were you when you had your last unusually good idea? What happened in the twenty-four hours before it? I’m collecting answers at leahgerber@outlook.com.

Topics

The same question, pointed at different rooms.

Everything here is one inquiry. These are the places it keeps turning up, and the questions waiting in each.

Work & Business

  • What changed around you before your work did?
  • Why do two people leave the same meeting with two different meetings?
  • What have you never told a manager because there was no safe way to say it?

Creativity

  • What happened in the 24 hours before your best work?

Memory & Learning

  • Why do I remember everything about you except your name?

Relationships & Family

  • Can two people be in the same room and not be in the same environment?
  • What happens to your conditions when you live inside someone else’s?
  • What does a relationship need before either person can say what they need?
  • What happens to a marriage lived in a second language?
  • Do two people become each other’s environment?

Age & Time

  • Do your conditions change as you age, or does the world stop making room for them?
  • What did you need at twenty-five that you no longer need?

Identity

  • What happens when your environment changes who you think you are?

Education

  • Are we measuring ability, or performance under conditions we chose?

Health & Performance

  • How much sleep do you need, and how would you know?
  • What kind of break do you actually need?
  • When does time speed up for you, and what was true when it did?

Home & Environment

  • What environment reliably makes you worse at something you’re normally good at?

Life Design

  • What if productivity isn’t the right outcome?

Find your own conditions

Questions to take home.

No score, no type, no result page. These are the questions I ask myself, written down so you can sit with them. A week will not prove anything, and I would rather say that than sell you something. It is long enough to give you a record of what actually happened, which is more than you have now.

The full version is a month of noticing — a self-observation guide, free, making no diagnostic claims. Three questions to start with.

Resources

What I’m reading.

A working library, with a note on what each one actually shows and where it stops. These come out of five verified research passes run in August 2026. Every pass also failed to cover things, and those gaps are recorded alongside the findings rather than smoothed over. Sources marked free can be read without a university login.

Within-person variation

  • Fleeson (2001), Journal of Personality and Social Psychology author copy free Shows: sampling people five times a day for weeks, one person’s variation in personality states rivals the differences between people’s averages. Stops: small student samples, self-report, and the result flips when measured against standard questionnaires. His own abstract also shows person averages are almost perfectly stable, which most citations leave out.
  • Fisher, Medaglia & Jeronimus (2018), PNAS free · PMC6142277 Shows: group and individual estimates diverge in spread and in correlations. Stops: the famous 7.85-to-1 ratio it is cited for is contested — the between-person figures appear to be spreads of averages, not of people, and I do not cite that number.
  • Adolf & Fried (2019) and the authors’ reply, PNAS free · PMC6452692, PMC6452707 Shows: the argument narrowing in real time. The reply concedes group-to-individual generalizability lies on a continuum. Stops: it is an exchange of letters, not a settled result.
  • Anvari et al. (2025), Personality and Social Psychology Bulletin free · PMC12044207 Shows: what people believe about their own variability and what repeated measurement finds correlate at only .14 to .30. Stops: seven days of sampling, so nothing about longer horizons.
  • Molenaar (2004), Measurement paywalled Shows: the mathematical argument that group statistics do not apply to individuals by default. Stops: it is an entailment about inference, not a measurement of how much anyone varies. I have only reached the abstract so far.

Sleep and insight

  • Wagner et al. (2004), Nature author copy free · counts at PMC3902672 Shows: 59% of a sleep group found a hidden rule against about 23% awake. Stops: 22 people per cell, one omnibus test at p = .03, no effect size or confidence interval anywhere in the paper.
  • Schonauer et al. (2018), Frontiers in Human Neuroscience free · PMC5834438 Shows: no sleep effect on classic insight puzzles, effect sizes near zero. Stops: a three-hour daytime sleep window rather than a full night.
  • Brodt et al. (2018), Sleep paywalled Shows: time away from a problem helped, and spending it asleep added nothing. The single most relevant paper here. Stops: I have read it through a secondary source and say so until I get the full text.
  • Lacaux et al. (2021), Science Advances free · PMC8654287 Shows: people who drifted into early-stage sleep found the rule far more often. Stops: nobody was assigned to a sleep stage, so it cannot separate the stage causing insight from insight-prone people drifting there.
  • Lowe et al. (2025), PLoS Biology free · PMC12200826 Shows: a preregistered failure to replicate the sleep-onset claim, with an unplanned deeper-sleep effect instead. Stops: the new effect was exploratory and carries the same sorting problem.
  • Cordi & Rasch (2021), Current Opinion in Neurobiology partly free Shows: the sleep-and-memory literature revised downward by one of its own principal authors. Stops: a review, not new data.

Person-environment fit

  • Kristof-Brown, Zimmerman & Johnson (2005), Personnel Psychology free copy online Shows: fit predicts how people feel about work, .44 to .56, and barely predicts what they produce, .07. Stops: correlational throughout, and the effects shrink hard when different people rate each side.
  • Kristof-Brown, Schneider & Su (2023), Personnel Psychology free preprint Shows: the field’s own stocktaking, eighteen years on, revising none of the numbers and calling causal direction unresolved. Stops: only a handful of within-person studies existed to review.
  • Bloom, Moen and colleagues, the STAR trial free · PMC6719311 Shows: a randomized workplace trial that gave employees schedule control. Performance barely moved. Stops: one intervention in one firm, and the outcomes were self-reported.
  • Edwards (1994), Organizational Behavior and Human Decision Processes free green copy Shows: the field’s own methods critique — difference scores confound what they claim to measure. Stops: methodological, so it bounds other findings rather than making its own.

Judging people, official versions

  • National Research Council (2003), The Polygraph and Lie Detection free at nationalacademies.org Shows: the polygraph beats chance on specific incidents and fails for security screening, because base rates defeat it. Also that the states it measures arise without deception. Stops: 2003, and lab-heavy.
  • Bond & DePaulo (2006), Personality and Social Psychology Review paywalled · abstract free Shows: people average 54% at spotting lies in real time, professionals included, and do better with ears than eyes. Stops: lab studies at even base rates, so not an operational estimate.
  • GAO reviews of TSA behavior detection (2010–2017) free at gao.gov Shows: 98% of the sources the agency cited for its behavioral indicators did not provide valid evidence. Stops: reviews of the evidence base, not of whether the program ever caught anyone.
  • Lenzenweger (2015), Journal of Personality Assessment free author copy Shows: the famous 1948 OSS assessment structure does not reproduce with modern methods. Stops: a reanalysis of the same published matrix, and it says nothing either way about whether the assessments predicted field performance. Nothing verified does.

Judgment and sequence

  • Danziger, Levav & Avnaim-Pesso (2011), PNAS free · PMC3084045 Shows: the famous hungry-judges pattern, favorable parole rulings falling across a session. Stops: archival, cases were not randomly ordered, and the reported effect is about fifty times larger than the mechanism proposed to explain it. I report it as contested and do not cite it as causal.
  • Glöckner (2016), Judgment and Decision Making free Shows: the effect-size arithmetic, d of roughly 1.96 against a proposed mechanism whose registered replication sits at 0.04, plus simulations where rational scheduling produces part of the curve. Stops: simulation, without access to the raw data.
  • Chen, Moskowitz & Shue (2016), Quarterly Journal of Economics free NBER working paper Shows: position in a sequence moves real decisions even when order is randomized and the merits are held fixed — loan officers, umpires, asylum judges. Stops: the mechanism is the gambler’s fallacy, not fatigue, and popular coverage merges the two.

Behind each entry sits a claim-by-claim audit trail with verbatim quotes, so anything I say from these can be traced to a page. If a note above overstates what a source shows, tell me and I will correct it in public.

About

Who is writing this.

I’m Leah Gerber. I’ve spent my career in restructuring and corporate development, inside firms whose entire value is people. I watched decisions about those people get made on averages and instinct.

My background is a BA in social science from Washington State, concentrated in human development, and an MBA from Grand Canyon University. That is enough to read the literature carefully and not enough to speak for it. I am not a psychologist and not a neuroscientist, and nothing here will pretend otherwise.

The labels on these essays say how much I actually know.

Evidence

What research actually demonstrates, cited, with its limits stated.

Suggestion

What the evidence tentatively points toward.

Hypothesis

What I think might follow. Mine, and unproven.

Observation

Something I or a reader noticed. A question generator, never proof.

Question

What I am asking. No answer implied yet.

If I ever blur them, call it out. Being publicly wrong and correcting it is the method working.