Reference · Reviewed 2026-05-10

Glossary

Plain-English definitions of 30 terms used across our guides. Each entry links to where the term is discussed in depth. Bookmarkable; each definition has a permalink anchor.

App Limit: A daily time cap on a specific app or category in iOS Screen Time or Android Digital Wellbeing. The limit triggers a friction screen when exceeded; on iOS it can be bypassed via "Ignore for today" unless a Screen Time passcode is set.
Algorithmic feed: A social media feed ordered by an engagement-prediction model rather than reverse chronological order. Optimised to maximise time-spent and reaction signals. Replaced reverse-chronological as the default in Twitter/X, Instagram, and Facebook between 2014-2018.
Attention economy: The market in which platforms compete for human attention as the scarce resource that monetises into advertising. Coined by Herbert Simon in 1971: "a wealth of information creates a poverty of attention."
Behavioural economics: A field combining economics and psychology to study how humans actually make decisions, including biases, heuristics, and deviations from rational-actor models. Foundational figures: Kahneman, Tversky, Thaler, Schelling, Ainslie.
Commitment device: A tool that lets present-you lock future-you into a decision, with a real consequence for breaking the commitment. Examples: money-stake contracts, automatic savings, alarm clock across the room, hard-block screen-time locks with verified exercise to unlock.
Cortisol loop: The repeated activation of stress hormones (cortisol) during sustained negative-content consumption. Distinct from dopamine-driven scroll loops because the chemistry is stress-anxiety rather than reward-seeking. Implicated in doomscrolling-mood-link studies.
Doomscrolling: The compulsive consumption of negative or endless feed content, usually on social media or news apps, often beyond the point at which the user wants to stop. Term entered popular use in 2020 during pandemic news consumption.
Downtime: iOS Screen Time feature that blocks all apps except those explicitly allowed during a scheduled window. Most useful pattern: 10 PM - 7 AM, with only Phone, Messages, FaceTime, and an alarm clock app permitted.
FamilyControls (entitlement): Apple iOS entitlement that grants third-party apps read access to Screen Time data and the ability to enforce limits. Required for apps like ScreenFine, Opal, and Jomo. Granted via individual application to Apple Developer Program; review can take weeks to months.
Fine jar: ScreenFine's mechanism for tracking screen-time overages. Each 15-minute block over the daily limit fires a lock event; target apps stay blocked until the user completes the chosen redemption action (25 pushups, 1,000 steps, 25 squats, or 10 mindful minutes). Lock events accumulate as a weekly log; no money is charged for them.
Friction tool: A behaviour-change app that adds resistance (a pause, a delay, a block) between user and target behaviour, without imposing a real consequence for ignoring the friction. Examples: One Sec, ScreenZen, Apple Screen Time. Effective for users with just-barely-enough self-control; insufficient for users whose self-control has been overwhelmed.
Gain framing: Communicating a behaviour-change benefit as a gain ("save 30 minutes a day"). Empirically weaker than loss framing per prospect theory. Gains are roughly half as motivating as equivalent losses.
Hyperbolic discounting: The empirical finding that humans irrationally prefer present rewards over future rewards, with the discount curve steeper than rational-actor models predict. Explains why calm-you wants to limit screen time and tired-you at 11pm overrides the limit.
Loss aversion: The finding that humans treat losing $X as roughly twice as motivating as gaining $X. Formalised by Kahneman and Tversky (1979) in prospect theory. The reason verified-exercise locks outperform notification-based reminders for behaviour change.
Money-stake contract: A behavioural commitment device where the user puts real money at risk against a goal. If the goal is met, money is returned; if not, money is forfeited (often to a charity or anti-charity). Examples: StickK, Beeminder, Forfeit. ScreenFine uses a related but non-monetary mechanism (verified exercise to clear an app lock); see "verified-exercise lock" below.
Nomophobia: No-mobile-phone phobia. The anxiety experienced when a phone is unavailable or out of reach. One of the earliest reliable signs of problematic phone use.
Phantom vibration: The sensation of feeling your phone vibrate when it has not. Reported by 70-90 percent of regular smartphone users. A neurological adaptation to anticipating notifications; tends to subside within 7-14 days of phone-free intervals.
Pre-commitment: The act of binding future-you to a decision while present-you is still calm and rational. Same idea as commitment device, often used interchangeably. Schelling's "Ulysses pact" framing is the canonical example.
Problematic smartphone use: The clinical term for what colloquially gets called "phone addiction." Distinguished from heavy use by interference with sleep, work, relationships, or mood. Not a recognised DSM-5 diagnosis but used widely in psychology research.
Prospect theory: Kahneman and Tversky's 1979 paper formalising loss aversion, framing effects, and probability weighting. Foundational document of behavioural economics; Kahneman won the Nobel prize for it in 2002.
Redemption window: ScreenFine's 1-week grace period after a lock event fires. The user clears the lock by completing a chosen behaviour: 1,000 steps, a workout, mindful minutes, camera-counted pushups or squats. Unredeemed events keep target apps blocked until the user acts; no money is charged.
Reels: Instagram's short-form video product, launched 2020 to compete with TikTok. Engineered with the same variable-reward feed architecture. Drives a disproportionate share of daily Instagram engagement.
Screen Time (Apple feature): iOS feature that tracks daily app usage and enforces user-set limits. Free, deeply integrated. Defeated for most users by the "Ignore for today" override unless a Screen Time passcode is set and held by someone else.
Short-form video: Vertical, sub-60-second video content optimised for swipe-driven feeds. Originated with TikTok (2018), now dominant on Reels, YouTube Shorts. Accounts for 47 percent of US mobile entertainment time as of 2026.
Skinner schedule (variable-ratio): B. F. Skinner's 1957 work showed that variable-ratio reinforcement schedules produce the most persistent behavioural patterns. The schedule slot machines and social-media feeds use. The reason scrolling is hard to stop.
Social comparison loop: The pattern of repeatedly viewing others' curated lives, comparing oneself unfavourably, and seeking more such content. Specific to image-led platforms (Instagram, TikTok). Distinct from doomscrolling because the dominant emotion is inadequacy rather than dread.
Speakable specification: A schema.org annotation telling voice assistants and AI ingestion which sentences on a page should be read aloud or extracted as a verbatim summary. Used on ScreenFine's pillar guides and data report.
Streak stake: ScreenFine's "Double or Nothing" gamble on the user's clean-day streak. Users stake N days of streak; if they survive 24h with zero overages, the staked days double. One slip-up loses all N (floor 0).
Ulysses pact: A pre-commitment named after Ulysses tying himself to the mast in the Odyssey so he could safely hear the sirens without steering toward them. The canonical commitment device example. Schelling popularised the term in The Strategy of Conflict (1960).
Wall of Shame: ScreenFine's opt-in public feed where overages and clean days are posted. Users control privacy via per-app and global toggles. External accountability layer on top of the financial mechanism.

From definitions to action

Most of the terms above describe mechanisms ScreenFine applies to one specific problem: phone screen time. Real money, real charges, real consequence.

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