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Co-founder of Greatr

Jeroen Snel

I bring Otto to life, and I write about habit research, focus and the iPhone settings that protect your attention.

Articles
8
Sources cited
32
Topics
5

Updated First article

I read the methods, not just the headline.

Hi, I’m Jeroen Snel, one of the two co-founders of Greatr, the iPhone app that stacks your habits into a morning or evening routine and keeps the apps you choose locked until you finish your routine. In the app, I bring Otto, your guide, to life and build his world, down to every medal you earn.

On the blog I write about how habits form, how to focus, and the iPhone settings that protect your attention. I am not a scientist or a clinician. I am the one who reads the methods section: how many people took part, what was measured, and whether anyone managed to repeat the result.

A headline is where I start reading, not where I stop.

Alongside the studies I read the books most people first meet these ideas in, like Deep Work by Cal Newport, The Power of Habit by Charles Duhigg, Indistractable by Nir Eyal and Four Thousand Weeks by Oliver Burkeman. Then I try what holds up on my own working days and turn it into steps you can take tomorrow.

What I write about

How I research

  1. Read the methods first.

    How many people took part, what was measured, how long it ran and how big the effect was. It is why our post on blocking apps says the gym effect in Katherine Milkman’s 2014 temptation bundling study faded over the following weeks.

  2. Check whether it replicated.

    When 23 labs repeated the ego depletion experiment in 2016 and found an effect close to zero, our post on discipline said so. When a 2022 replication did not find the drain from a phone on your desk, our focus post said that too.

  3. Check the settings myself.

    For iPhone guides I follow Apple’s own documentation and go through the steps on an iPhone, and I say so when Apple has renamed a menu.

Every article I write follows our editorial policy. Spotted a mistake? Email hello@getgreatr.app and we will look into it. A post’s date changes only when its content does.

Research I cite

32 sources cited across Jeroen Snel’s 8 articles, most cited first. 27 of them link to a DOI, PubMed or PMC record.

  1. How are habits formed: Modelling habit formation in the real world

    Phillippa Lally and colleagues, European Journal of Social Psychology, 2010DOI

    Cited in How Long Does It Take to Form a Habit? What the Research Says, How to Build Discipline and How to Stay Consistent

  2. Holding the Hunger Games Hostage at the Gym: An Evaluation of Temptation Bundling

    Katherine Milkman, Julia Minson and Kevin Volpp, Management Science, 2014DOI

    Cited in How to Block Apps on iPhone Until Your Habits Are Done and How to Stay Consistent

  3. Set schedules with Screen Time on iPhone (iPhone User Guide)

    Apple Support, 2026

    Cited in How to Block Apps on iPhone Until Your Habits Are Done

  4. Use Screen Time on your iPhone and iPad

    Apple Support, 2026

    Cited in How to Reduce Screen Time

  5. Time to Form a Habit: A Systematic Review and Meta-Analysis of Health Behaviour Habit Formation and Its Determinants

    Ben Singh and colleagues, Healthcare (MDPI), 2024DOI

    Cited in How Long Does It Take to Form a Habit? What the Research Says

  6. Suffering from problematic smartphone use? Why not use grayscale setting as an intervention! An experimental study

    Lea Christin Wickord and Claudia Quaiser-Pohl, Computers in Human Behavior Reports, 2023DOI

    Cited in How to Reduce Screen Time

  7. Digital Addiction

    Hunt Allcott, Matthew Gentzkow and Lena Song, American Economic Review, 2022DOI

    Cited in How to Reduce Screen Time

  8. Reexamining the "brain drain" effect: A replication of Ward et al. (2017)

    Acta Psychologica, 2022DOI

    Cited in How to Focus

Show 24 more sourcesShow fewer
  1. Habit formation following routine-based versus time-based cue planning: A randomized controlled trial

    Jan Keller and colleagues, British Journal of Health Psychology, 2021DOI

    Cited in How Long Does It Take to Form a Habit? What the Research Says

  2. Meet the Screen Time API (WWDC21)

    Apple Developer, 2021

    Cited in How to Block Apps on iPhone Until Your Habits Are Done

  3. Megastudies improve the impact of applied behavioural science

    Katherine Milkman and colleagues, Nature, 2021DOI

    Cited in How to Stay Consistent

  4. Batching smartphone notifications can improve well-being

    Nicholas Fitz and colleagues, Computers in Human Behavior, 2019DOI

    Cited in How to Reduce Screen Time

  5. Before-bedtime passive body heating by warm shower or bath to improve sleep: A systematic review and meta-analysis

    Sleep Medicine Reviews, 2019DOI

    Cited in Evening Routine

  6. Brief, daily meditation enhances attention, memory, mood, and emotional regulation in non-experienced meditators

    Julia Basso and colleagues, Behavioural Brain Research, 2019PubMed

    Cited in Meditation for Beginners

  7. Effects of Evening Exercise on Sleep in Healthy Participants: A Systematic Review and Meta-Analysis

    Sports Medicine, 2019PubMed

    Cited in Evening Routine

  8. No More FOMO: Limiting Social Media Decreases Loneliness and Depression

    Melissa Hunt and colleagues, Journal of Social and Clinical Psychology, 2018DOI

    Cited in How to Block Apps on iPhone Until Your Habits Are Done

  9. Brain Drain: The Mere Presence of One's Own Smartphone Reduces Available Cognitive Capacity

    Adrian Ward and colleagues, Journal of the Association for Consumer Research, 2017DOI

    Cited in How to Focus

  10. A Multilab Preregistered Replication of the Ego-Depletion Effect

    Martin Hagger, Nikos Chatzisarantis and colleagues, Perspectives on Psychological Science, 2016DOI

    Cited in How to Build Discipline

  11. Does Monitoring Goal Progress Promote Goal Attainment? A Meta-Analysis of the Experimental Evidence

    Benjamin Harkin and colleagues, Psychological Bulletin, 2016DOI

    Cited in How to Stay Consistent

  12. Situational Strategies for Self-Control

    Angela Duckworth, Tamar Gendler and James Gross, Perspectives on Psychological Science, 2016PMC

    Cited in How to Build Discipline

  13. Evening use of light-emitting eReaders negatively affects sleep, circadian timing, and next-morning alertness

    Proceedings of the National Academy of Sciences, 2015DOI

    Cited in Evening Routine

  14. More Than Resisting Temptation: Beneficial Habits Mediate the Relationship Between Self-Control and Positive Life Outcomes

    Brian Galla and Angela Duckworth, Journal of Personality and Social Psychology, 2015DOI

    Cited in How to Build Discipline

  15. Recommended Amount of Sleep for a Healthy Adult: A Joint Consensus Statement of the American Academy of Sleep Medicine and Sleep Research Society

    Journal of Clinical Sleep Medicine, 2015

    Cited in Evening Routine

  16. The Attentional Cost of Receiving a Cell Phone Notification

    Cary Stothart and colleagues, Journal of Experimental Psychology: Human Perception and Performance, 2015DOI

    Cited in How to Focus

  17. Meditation Programs for Psychological Stress and Well-being: A Systematic Review and Meta-analysis

    JAMA Internal Medicine, 2014DOI

    Cited in Meditation for Beginners

  18. The Fresh Start Effect: Temporal Landmarks Motivate Aspirational Behavior

    Hengchen Dai, Katherine Milkman and Jason Riis, Management Science, 2014DOI

    Cited in How to Stay Consistent

  19. Caffeine Effects on Sleep Taken 0, 3, or 6 Hours before Going to Bed

    Journal of Clinical Sleep Medicine, 2013PMC

    Cited in Evening Routine

  20. Making health habitual: the psychology of 'habit-formation' and general practice

    Benjamin Gardner, Phillippa Lally and Jane Wardle, British Journal of General Practice, 2012PMC

    Cited in How Long Does It Take to Form a Habit? What the Research Says

  21. A Wandering Mind Is an Unhappy Mind

    Matthew Killingsworth and Daniel Gilbert, Science, 2010DOI

    Cited in Meditation for Beginners

  22. Why is it so hard to do my work? The challenge of attention residue when switching between work tasks

    Sophie Leroy, Organizational Behavior and Human Decision Processes, 2009DOI

    Cited in How to Focus

  23. The Cost of Interrupted Work: More Speed and Stress

    Gloria Mark, Daniela Gudith and Ulrich Klocke, Proceedings of CHI 2008 (ACM), 2008

    Cited in How to Focus

  24. Implementation Intentions and Goal Achievement: A Meta-analysis of Effects and Processes

    Peter Gollwitzer and Paschal Sheeran, Advances in Experimental Social Psychology, 2006DOI

    Cited in How to Build Discipline

What I read

Jip Groen and I have both read all 17 of these, roughly from the best known down. Books give us the language; the studies above decide what we claim.

  1. Atomic Habits

    James Clear, 2018

    Small habits, stacked in a fixed order: the idea our routines are built on.

    Mentioned in Habit Stacking.

  2. The Power of Habit

    Charles Duhigg, 2012

    The cue, routine and reward loop, and why you change a habit by keeping the cue and swapping the routine.

  3. The 7 Habits of Highly Effective People

    Stephen R. Covey, 1989

    Effectiveness as a matter of character, built through seven habits, from being proactive to sharpening the saw.

  1. Thinking, Fast and Slow

    Daniel Kahneman, 2011

    Two ways of thinking, fast intuition and slow deliberation, and the predictable mistakes the fast one makes.

  2. Mindset

    Carol S. Dweck, 2006

    Why believing your abilities can grow changes how you meet effort, feedback and setbacks.

  3. Deep Work

    Cal Newport, 2016

    Focused, undistracted work as a skill you can train, and a rarer one every year.

    Mentioned in How to Focus.

  4. Tiny Habits

    BJ Fogg, 2019

    Start so small you cannot fail, and anchor the new habit to something you already do.

    Mentioned in Habit Stacking.

  5. Grit

    Angela Duckworth, 2016

    Passion and perseverance for long-term goals, and why sustained effort can count as much as talent.

    The author’s studies are cited in How to Build Discipline.

  6. Essentialism

    Greg McKeown, 2014

    Doing less, but better: deciding what really matters and saying no to the rest.

Show 8 more booksShow fewer

  1. The Miracle Morning

    Hal Elrod, 2012

    A morning routine of six short practices, from silence and affirmations to reading and journaling, before the day begins.

  2. Digital Minimalism

    Cal Newport, 2019

    Choose the few apps that serve you on purpose, and let the rest go.

  3. Indistractable

    Nir Eyal, 2019

    Distraction often starts with a feeling, so the fix starts there too, not only with the phone.

  4. Four Thousand Weeks

    Oliver Burkeman, 2021

    A life is about four thousand weeks long, so choosing what to leave undone is the real skill.

  5. Stolen Focus

    Johann Hari, 2022

    Why so many of us struggle to pay attention, and the forces in modern life that pull it away.

  6. Dopamine Nation

    Anna Lembke, 2021

    A psychiatrist on the balance between pleasure and pain, and why a steady supply of easy rewards can leave us wanting more.

  7. Good Habits, Bad Habits

    Wendy Wood, 2019

    A habit researcher on why so much of what we repeat runs on context rather than willpower, and how to shape that context.

    The author’s studies are cited in Dopamine Detox and How to Break a Bad Habit.

  8. Flow

    Mihaly Csikszentmihalyi, 1990

    The psychologist who named flow, on the deep absorption that can make hard work feel rewarding.

Articles by Jeroen Snel

8 articles, newest first.

  1. Focus

    How to Focus: Phone-Free Sessions for Deep Work

    7 min read5 sources

  2. Screen time

    How to Block Apps on iPhone Until Your Habits Are Done

    8 min read4 sources

  3. Habits

    How Long Does It Take to Form a Habit? What the Research Says

    9 min read4 sources

  4. Screen time

    How to Reduce Screen Time: 8 Changes That Actually Stick

    8 min read4 sources

  5. Routines

    Evening Routine: A Simple Wind-Down Plan for Better Sleep

    8 min read5 sources

  6. Habits

    How to Build Discipline: Let Habits Do the Heavy Lifting

    7 min read5 sources

  7. Mindfulness

    Meditation for Beginners: How to Meditate in 5 Simple Steps

    7 min read3 sources

  8. Habits

    How to Stay Consistent: 6 Rules for When Motivation Fades

    7 min read5 sources

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