interface:
  display_name: "Suede Marketing Psychology"
  short_description: "Apply behavioural science honestly"
  default_prompt: "Use $suede-marketing-psychology on [target]. The user wants persuasion principles, cognitive biases, or behavioural science applied to a marketing decision. Work through anchoring, social proof, loss aversion, framing, and the mental models behind why people actually buy, ground every recommendation in evidence the user can check, and return the decisions, the reasoning, and what to measure next."
policy:
  allow_implicit_invocation: true

{
  "skill_name": "suede-marketing-psychology",
  "evals": [
    {
      "id": 1,
      "prompt": "How can I use psychology to increase conversions on our pricing page? We sell a B2B SaaS tool with three tiers ($29, $79, $199/month).",
      "expected_output": "Should check for product-marketing.md first. Should apply relevant pricing psychology models: anchoring (show the highest plan first or use a decoy), charm pricing (consider $29 vs $30), Rule of 100 (percentage vs dollar discounts), Good-Better-Best framing, loss aversion (show what they miss on lower tiers). Should also apply broader persuasion models: social proof near pricing, scarcity for limited-time offers, default effect (pre-select recommended plan). Should provide specific, actionable recommendations tied to their price points.",
      "assertions": [
        "Checks for product-marketing.md",
        "Applies pricing psychology models (anchoring, charm pricing, Rule of 100)",
        "Applies Good-Better-Best framing",
        "Applies loss aversion to tier differentiation",
        "Applies social proof near pricing",
        "Provides specific recommendations for their price points",
        "References specific mental models by name"
      ],
      "files": []
    },
    {
      "id": 2,
      "prompt": "Explain the scarcity principle and how to use it ethically in SaaS marketing without being manipulative.",
      "expected_output": "Should explain scarcity as a mental model (limited availability increases perceived value). Should provide legitimate SaaS applications: limited beta spots, early-bird pricing with real deadlines, limited-time feature access, cohort-based launches. Should distinguish ethical scarcity (real constraints) from manufactured urgency (fake countdown timers, artificial limits). Should provide specific examples and implementation guidance. Should reference related models (urgency, FOMO, loss aversion).",
      "assertions": [
        "Explains scarcity principle clearly",
        "Provides legitimate SaaS applications",
        "Distinguishes ethical from manipulative use",
        "Provides specific examples",
        "References related mental models",
        "Addresses ethical considerations directly"
      ],
      "files": []
    },
    {
      "id": 3,
      "prompt": "what psychological principles should I use to write better marketing copy?",
      "expected_output": "Should trigger on casual phrasing. Should recommend copy-relevant mental models from the skill's taxonomy: social proof, reciprocity, loss aversion, anchoring, scarcity, IKEA Effect, Endowment Effect, Commitment & Consistency. For each principle, should explain what it is and provide a specific copywriting application. Should reference the quick reference table by challenge. Should organize by where in the copy each principle applies (headlines, body, CTAs, testimonials).",
      "assertions": [
        "Triggers on casual phrasing",
        "Recommends copy-relevant mental models",
        "Explains each principle briefly",
        "Provides specific copywriting application per principle",
        "Organizes by where each applies in copy",
        "References multiple model categories"
      ],
      "files": []
    },
    {
      "id": 4,
      "prompt": "I'm designing an onboarding flow and want to use behavioral psychology to increase activation. What models should I apply?",
      "expected_output": "Should apply design and behavioral models from the skill's taxonomy: Goal-Gradient Effect (motivation increases near goal), Hick's Law (reduce choices), IKEA Effect (let users build something), Endowment Effect (let them experience ownership), Zeigarnik Effect (incomplete tasks drive completion), Commitment & Consistency (small asks first). Should explain how each applies to onboarding specifically. Should provide actionable recommendations for each model.",
      "assertions": [
        "Applies Goal-Gradient Effect",
        "Applies Hick's Law",
        "Applies IKEA Effect or Endowment Effect",
        "Applies Zeigarnik Effect or commitment principles",
        "Explains how each applies to onboarding",
        "Provides actionable recommendations per model"
      ],
      "files": []
    },
    {
      "id": 5,
      "prompt": "What's the psychology behind why free trials work better than freemium for some products?",
      "expected_output": "Should apply relevant mental models: loss aversion (trial users fear losing access), endowment effect (they feel ownership after using), sunk cost (time invested during trial), Zero-Price Effect (free removes psychological barrier to start), status quo bias (inertia to keep what they have). Should explain how these models interact in trial vs freemium contexts. Should note when each model works best (trial for products with high activation effort, freemium for products with network effects).",
      "assertions": [
        "Applies loss aversion to trial context",
        "Applies endowment effect",
        "Applies Zero-Price Effect",
        "Explains how models interact in trial vs freemium",
        "Notes when each approach works best",
        "Provides clear, educational explanation"
      ],
      "files": []
    },
    {
      "id": 6,
      "prompt": "Help me run an A/B test on which psychological principle works better for our CTA — scarcity vs social proof.",
      "expected_output": "Should recognize this is an A/B test setup task, not a psychology task. Should defer to or cross-reference suede-ab-testing for the experiment design. May provide psychological context on both principles to inform the hypothesis, but should make clear that suede-ab-testing owns test design and analysis.",
      "assertions": [
        "Recognizes this as an A/B test setup task",
        "References or defers to suede-ab-testing",
        "May provide psychological context for hypothesis",
        "Does not attempt full test design using psychology patterns"
      ],
      "files": []
    }
  ]
}

# Model Catalog

The full library of models behind `suede-marketing-psychology`. Read this after the Quick Reference table in SKILL.md has narrowed the challenge to two or three candidate models — pull only those entries, not the whole file.

## Evidence tiers

Every entry carries exactly one tier. The tier is what makes the skill's promise to "state its evidence limits" operable at the entry level, and it is a closed vocabulary — never invent a sixth label or leave one blank.

| Tier | Means |
|---|---|
| **Robust** | Replicated across independent studies and settings. Still a hypothesis in *your* context, but the mechanism is not in dispute. |
| **Context-dependent** | Real, but effect size and direction swing with audience, category, price point, or framing. Do not port a published effect size into your funnel. |
| **Contested** | Replication is mixed or the headline version overstates the finding. Use only as an idea to test, never as a reason. |
| **Folklore** | Trade lore with no controlled basis. Cite it to nobody; test it or drop it. |
| **Framework** | A way of organizing a decision, not an empirical effect. Cannot be "true" or "false" — only useful or not for this problem. |

## Contents

- [Foundational Thinking Models](#foundational-thinking-models) — strategy framing: First Principles, Jobs to Be Done, Circle of Competence, Inversion, Local vs. Global Optima, Theory of Constraints, Second-Order Thinking, Probabilistic Thinking, Barbell Strategy
- [Understanding Buyers & Human Psychology](#understanding-buyers--human-psychology) — how customers decide: attribution, exposure, availability, confirmation, Lindy, mimetic desire, sunk cost, endowment, IKEA, zero-price, present bias, status quo, defaults, choice overload, goal gradient, peak-end, Zeigarnik, pratfall, curse of knowledge, mental accounting, regret aversion, social proof
- [Influencing Behavior & Persuasion](#influencing-behavior--persuasion) — reciprocity, commitment, authority, liking, unity, scarcity, foot-in-the-door, door-in-the-face, loss aversion, anchoring, decoy, framing, contrast
- [Pricing Psychology](#pricing-psychology) — charm pricing, rounded-price fluency, Rule of 100, price relativity, mental accounting
- [Design & Delivery Models](#design--delivery-models) — Hick's Law, AIDA, Rule of 7, nudge/choice architecture, BJ Fogg, EAST, COM-B, activation energy, north-star metric, Cobra effect
- [Growth & Scaling Models](#growth--scaling-models) — feedback loops, compounding, network effects, flywheel, switching costs, exploration vs. exploitation, critical mass, survivorship bias

---

## Foundational Thinking Models

These models sharpen strategy and help you solve the right problem.

### First Principles
**Evidence: Framework.** Break problems down to basic truths and build solutions from there. Instead of copying competitors, ask "why" repeatedly to find root causes.

**Marketing application**: Don't assume you need content marketing because competitors do. Ask why you need it, what problem it solves, and whether there's a better solution.

### Jobs to Be Done
**Evidence: Framework.** People don't buy products—they "hire" them to get a job done. Focus on the outcome customers want, not features.

**Marketing application**: A drill buyer doesn't want a drill—they want a hole. Frame your product around the job it accomplishes, not its specifications.

### Circle of Competence
**Evidence: Framework.** Know what you're good at and stay within it. Venture outside only with proper learning or expert help.

**Marketing application**: Don't chase every channel. Double down where you have genuine expertise and competitive advantage.

### Inversion
**Evidence: Framework.** Instead of asking "How do I succeed?", ask "What would guarantee failure?" Then avoid those things.

**Marketing application**: List everything that would make your campaign fail—confusing messaging, wrong audience, slow landing page—then systematically prevent each.

### Local vs. Global Optima
**Evidence: Framework.** A local optimum is the best solution nearby; a global optimum is the best overall. Don't get stuck optimizing the wrong thing.

**Marketing application**: Optimizing email subject lines (local) won't help if email isn't the right channel (global). Zoom out before zooming in.

### Theory of Constraints
**Evidence: Framework.** Every system has one bottleneck limiting throughput. Find and fix that constraint before optimizing elsewhere.

**Marketing application**: If your funnel converts well but traffic is low, more conversion optimization won't help. Fix the traffic bottleneck first.

### Second-Order Thinking
**Evidence: Framework.** Consider not just immediate effects, but the effects of those effects.

**Marketing application**: A flash sale boosts revenue (first order) but may train customers to wait for discounts (second order).

### Probabilistic Thinking
**Evidence: Framework.** Think in probabilities, not certainties. Estimate likelihoods and plan for multiple outcomes.

**Marketing application**: Don't bet everything on one campaign. Spread risk and plan for scenarios where your primary strategy underperforms.

### Barbell Strategy
**Evidence: Framework.** Combine extreme safety with small high-risk/high-reward bets. Avoid the mediocre middle. The commonly quoted 80/20 split is a convention, not a finding.

**Marketing application**: Most of the budget into proven channels, a bounded slice into experimental bets the company can afford to lose.

---

## Understanding Buyers & Human Psychology

These models explain how customers think, decide, and behave.

### Fundamental Attribution Error
**Evidence: Context-dependent.** People attribute others' behavior to character rather than circumstances; the magnitude varies across cultures and settings. "They didn't buy because they're not serious" vs. "The checkout was confusing."

**Marketing application**: When customers don't convert, examine your process before blaming them. The problem is usually situational, not personal.

### Mere Exposure Effect
**Evidence: Robust.** People tend to prefer things they've seen before; supported by large meta-analyses, though it can reverse with overexposure to a disliked stimulus.

**Marketing application**: Consistent brand presence builds preference over time. Repetition across channels creates comfort and trust.

### Availability Heuristic
**Evidence: Robust.** People judge likelihood by how easily examples come to mind. Recent or vivid events seem more common.

**Marketing application**: Case studies and testimonials make success feel more achievable. Make positive outcomes easy to imagine.

### Confirmation Bias
**Evidence: Robust.** People seek information confirming existing beliefs and discount contradictory evidence.

**Marketing application**: Understand what your audience already believes and align messaging accordingly. Fighting beliefs head-on rarely works.

### The Lindy Effect
**Evidence: Framework.** The longer a non-perishable idea has survived, the longer it may continue. A heuristic about survival odds, not a measured effect.

**Marketing application**: Durable principles (clear value props, social proof) tend to outlast trendy tactics. Don't abandon fundamentals for fads.

### Mimetic Desire
**Evidence: Framework.** Girard's theory that desire is socially contagious — people want things because others want them. Philosophical, not experimentally established.

**Marketing application**: Show that people your audience identifies with want the product. Waitlists, exclusivity, and social proof lean on this.

### Sunk Cost Fallacy
**Evidence: Robust.** People continue investing because of past investment, even when it's no longer rational.

**Marketing application**: Know when to kill underperforming campaigns. Past spend shouldn't justify future spend if results aren't there.

### Endowment Effect
**Evidence: Context-dependent.** People often value things more once they own them, but the effect shrinks or vanishes with trading experience and in some market settings.

**Marketing application**: Free trials, samples, and freemium models let customers "own" the product, which can make them reluctant to give it up.

### IKEA Effect
**Evidence: Context-dependent.** Effort invested in creating something can raise its perceived value — demonstrated mainly in lab tasks with successful completion; failure reverses it.

**Marketing application**: Let customers customize or configure something, but only where they will succeed. A half-finished setup destroys the effect.

### Zero-Price Effect
**Evidence: Context-dependent.** "Free" behaves differently from a very low price in several replicated studies, with effect size varying by category and by what the free option costs in attention.

**Marketing application**: Free tiers, trials, and shipping have outsized appeal; measure whether the free cohort ever converts before scaling it.

### Hyperbolic Discounting / Present Bias
**Evidence: Robust.** People prefer immediate rewards over larger future ones, and discount steeply at short horizons.

**Marketing application**: Emphasize immediate benefits ("Start saving time today") over deferred ones ("You'll see ROI in 6 months").

### Status-Quo Bias
**Evidence: Robust.** People prefer the current state; change requires effort and feels risky.

**Marketing application**: Reduce friction to switch. Make the transition feel safe and easy. "Import your data in one click."

### Default Effect
**Evidence: Robust.** Defaults strongly shape choice, with large field evidence (enrollment, organ donation). Note that using them for recurring charges is a legal and ethical question, not just a conversion one.

**Marketing application**: Preselect the option that is genuinely best for most customers, disclose it plainly, and never preselect a charge the user did not ask for.

### Paradox of Choice
**Evidence: Contested.** Meta-analyses of choice overload find a mean effect near zero; overload appears only under specific conditions (time pressure, unclear preferences, complex options).

**Marketing application**: Fewer tiers may help, but treat "three beats seven" as a hypothesis to test on your own pricing page, not a rule.

### Goal-Gradient Effect
**Evidence: Context-dependent.** Effort accelerating near a goal is replicated in loyalty-program field data; the size depends on how visible and credible the progress signal is.

**Marketing application**: Show progress bars, completion percentages, and "almost there" messaging — with honest denominators.

### Peak-End Rule
**Evidence: Context-dependent.** Retrospective evaluations weight peak and end moments heavily in several domains, but do not fully replace duration and average in all settings.

**Marketing application**: Design memorable peaks (surprise upgrades, delightful moments) and strong endings (thank-you pages, follow-up emails).

### Zeigarnik Effect
**Evidence: Contested.** The original memory finding replicates inconsistently, and the marketing version ("open loops create pull") is an extrapolation.

**Marketing application**: "You're 80% done" and abandoned-cart reminders are worth testing; do not present the pull as established.

### Pratfall Effect
**Evidence: Contested.** The original result depended on the actor's perceived competence, and replications are mixed.

**Marketing application**: Admitting a weakness ("We're not the cheapest, but...") can build trust when your competence is already established. Test it.

### Curse of Knowledge
**Evidence: Robust.** Once you know something, you systematically overestimate how obvious it is to others.

**Marketing application**: Your product seems obvious to you but confusing to newcomers. Test copy with people unfamiliar with your space.

### Mental Accounting
**Evidence: Robust.** People treat money differently by source or intended use, even though money is fungible.

**Marketing application**: Frame costs in favorable mental accounts. "$3/day" reads differently than "$90/month" for the same amount.

### Regret Aversion
**Evidence: Context-dependent.** Anticipated regret shifts choices in many studies, with size depending on how vividly the alternative is imagined.

**Marketing application**: Address regret directly. Money-back guarantees, free trials, and "no commitment" messaging reduce the felt risk.

### Bandwagon Effect / Social Proof
**Evidence: Robust.** Descriptive-norm information reliably shifts behavior in field experiments, though it can backfire when the norm you reveal is the undesired one.

**Marketing application**: Show customer counts, testimonials, logos, and reviews — but never advertise a low number as if it were high.

---

## Influencing Behavior & Persuasion

These models help you ethically influence customer decisions.

### Reciprocity Principle
**Evidence: Robust.** Unsolicited gifts and favors raise compliance across many field settings.

**Marketing application**: Free content, free tools, and generous free tiers create goodwill. Give value before asking for anything.

### Commitment & Consistency
**Evidence: Context-dependent.** People act consistently with prior commitments, more strongly when the commitment was active, public, and voluntary.

**Marketing application**: Get small voluntary commitments first (email signup, free trial) rather than coerced ones.

### Authority Bias
**Evidence: Context-dependent.** Deference to credentialed sources is well documented, but the persuasive lift depends on the audience accepting the credential as relevant.

**Marketing application**: Feature expert endorsements and certifications your specific buyer already respects; irrelevant logos add nothing.

### Liking / Similarity Bias
**Evidence: Context-dependent.** Similarity and liking raise compliance in many studies; effect sizes are modest and easily swamped by product fit.

**Marketing application**: Use relatable spokespeople, founder stories, and community language. "Built by marketers for marketers" signals similarity.

### Unity Principle
**Evidence: Context-dependent.** Shared-identity framing outperforms mere liking in Cialdini's later work; independent replication is thinner than for the classic six.

**Marketing application**: Position the brand as part of the customer's group using language that group actually uses.

### Scarcity / Urgency Heuristic
**Evidence: Context-dependent.** Genuine scarcity raises perceived value; manufactured scarcity damages trust when detected, and can be a legal problem in some jurisdictions.

**Marketing application**: Limited-time offers and low-stock indicators — only when literally true, with the real number.

### Foot-in-the-Door Technique
**Evidence: Context-dependent.** Meta-analyses find a small but real effect, conditional on the first request being genuinely small and freely accepted.

**Marketing application**: Free trial → paid plan → annual plan. Each step should stand on its own value, not on the previous commitment.

### Door-in-the-Face Technique
**Evidence: Context-dependent.** Small meta-analytic effect that requires the same requester, an immediate second ask, and a first request that is large but not absurd.

**Marketing application**: Showing an enterprise tier before the starter plan can reframe the price. Absurd anchors read as manipulation and cost trust.

### Loss Aversion / Prospect Theory
**Evidence: Context-dependent.** Losses loom larger than gains in risky choice, but the popular "roughly 2×" ratio is not a constant, and loss framing does not reliably beat gain framing in marketing copy.

**Marketing application**: Test loss framing ("Don't miss out") against gain framing rather than assuming loss wins.

### Anchoring Effect
**Evidence: Robust.** The first number presented shifts subsequent numeric judgments, replicated widely, including with knowledgeable participants.

**Marketing application**: Show the higher price first (original price, competitor price, enterprise tier) to set the reference point — honestly.

### Decoy Effect
**Evidence: Contested.** The asymmetric-dominance result is well known but fails to replicate in many real-product and real-money settings.

**Marketing application**: A third tier may clarify the comparison, but do not count on a designed decoy to move choice. Measure it.

### Framing Effect
**Evidence: Robust.** Logically equivalent presentations produce different choices; among the most replicated findings in the field.

**Marketing application**: "90% success rate" and "10% failure rate" land differently. Choose the honest frame that matches the decision at hand.

### Contrast Effect
**Evidence: Robust.** Judgments shift relative to what is presented alongside; broadly replicated in perception and evaluation.

**Marketing application**: Show the "before" state clearly. The contrast with your "after" makes improvements vivid.

---

## Pricing Psychology

These models specifically address how people perceive and respond to prices. Pair with `suede-pricing` for architecture; this section is about perception only.

### Charm Pricing / Left-Digit Effect
**Evidence: Context-dependent.** Left-digit effects appear in scanner and field data for value-positioned goods; they are weak or absent for premium and subscription B2B pricing.

**Marketing application**: Consider .99/.95 endings for value-focused products; test rather than assume, especially above $100.

### Rounded-Price (Fluency) Effect
**Evidence: Contested.** The "round = premium, precise = value" claim rests on a small set of studies with mixed follow-ups.

**Marketing application**: Treat round versus charm pricing as an A/B test, not a rule about your brand's tier.

### Rule of 100
**Evidence: Folklore.** A widely repeated copywriting heuristic (percentages under $100, absolute amounts over) with no substantial controlled basis.

**Marketing application**: Use it to generate two discount presentations to test. Do not cite it as a reason.

### Price Relativity / Good-Better-Best
**Evidence: Context-dependent.** Prices are judged relative to the presented set; which tier wins depends on the specific spread and on how the tiers differ in substance.

**Marketing application**: Three tiers where the middle is your target — verified against actual tier-selection data, not assumed.

### Mental Accounting (Pricing)
**Evidence: Context-dependent.** Reframing the same amount across time units changes perceived cost in several studies; the effect narrows when buyers do the arithmetic.

**Marketing application**: "$1/day" versus "$30/month" is worth testing. Never use the frame to obscure the total charged.

---

## Design & Delivery Models

These models help you design effective marketing systems.

### Hick's Law
**Evidence: Context-dependent.** Established for simple choice-reaction time with equally likely options; extrapolating it to landing-page conversion is an inference, not a measured result.

**Marketing application**: Simplify choices — one clear CTA, fewer form fields — and measure completion rather than citing the law.

### AIDA Funnel
**Evidence: Framework.** Attention → Interest → Desire → Action. A century-old organizing model, never an empirically validated sequence.

**Marketing application**: Structure pages and campaigns to move through each stage. Capture attention before building desire.

### Rule of 7
**Evidence: Folklore.** Trade lore originating in 1930s film marketing. No controlled basis for the number seven, and effective frequency varies enormously by category.

**Marketing application**: Build multi-touch campaigns, but derive the touch count from your own attribution data. Never quote "7" to a client as a finding.

### Nudge Theory / Choice Architecture
**Evidence: Context-dependent.** Nudges work, but pooled effect sizes shrink substantially once publication bias is corrected, and some categories (defaults) far outperform others (framing prompts).

**Marketing application**: Prefer structural nudges (defaults, ordering, friction removal) over persuasive ones, and measure each.

### BJ Fogg Behavior Model
**Evidence: Framework.** Behavior = Motivation × Ability × Prompt. A design heuristic for diagnosing which factor is missing.

**Marketing application**: High motivation but hard to do = won't happen. Easy to do but no prompt = won't happen. Design for all three.

### EAST Framework
**Evidence: Framework.** Make desired behaviors Easy, Attractive, Social, Timely. A checklist distilled from behavioral-insights practice.

**Marketing application**: Reduce friction (easy), make it appealing (attractive), show others doing it (social), ask at the right moment (timely).

### COM-B Model
**Evidence: Framework.** Behavior requires Capability, Opportunity, Motivation. Used as a diagnostic in behavior-change design.

**Marketing application**: Can they do it (capability)? Is the path clear (opportunity)? Do they want to (motivation)? Address all three.

### Activation Energy
**Evidence: Framework.** A borrowed metaphor: the initial effort required to start blocks action even when the whole task is easy.

**Marketing application**: Reduce starting friction. Pre-fill forms, offer templates, show quick wins. Make the first step trivially easy.

### North Star Metric
**Evidence: Framework.** An alignment device for picking one measure that captures delivered value. Its usefulness depends entirely on picking the right one.

**Marketing application**: Identify your north star (active users, completed projects, revenue per customer) and align efforts toward it.

### The Cobra Effect
**Evidence: Framework.** A cautionary pattern about incentives producing the opposite of the intended result.

**Marketing application**: Test incentive structures. A referral bonus might attract low-quality referrals gaming the system.

---

## Growth & Scaling Models

These models explain how marketing compounds and scales.

### Feedback Loops
**Evidence: Framework.** Output becomes input, creating cycles. Positive loops accelerate growth; negative loops create decline.

**Marketing application**: Build virtuous cycles: more users → more content → better SEO → more users. Identify and strengthen positive loops.

### Compounding
**Evidence: Framework.** Small consistent gains accumulate. The math is real; whether your channel actually compounds is an empirical question.

**Marketing application**: Content, SEO, and brand can compound — verify with cohort data before promising a curve.

### Network Effects
**Evidence: Context-dependent.** Well documented in specific markets (marketplaces, communication tools); frequently claimed for products that have none.

**Marketing application**: Design features that genuinely improve with more users. If value doesn't change with scale, don't claim a network effect.

### Flywheel Effect
**Evidence: Framework.** Sustained effort creates momentum that becomes self-maintaining. A narrative model from business writing.

**Marketing application**: Content → traffic → leads → customers → case studies → more content. Each element powers the next.

### Switching Costs
**Evidence: Context-dependent.** Switching costs measurably raise retention in several industries; raising them deliberately trades retention against goodwill and can attract regulatory attention.

**Marketing application**: Increase switching costs through accumulated value (integrations, data, workflow), never through obstruction.

### Exploration vs. Exploitation
**Evidence: Framework.** The multi-armed-bandit trade-off applied to channel investment.

**Marketing application**: Don't abandon working channels for shiny new ones, but allocate a bounded budget to experiments.

### Critical Mass / Tipping Point
**Evidence: Framework.** The threshold after which growth becomes self-sustaining. Identifiable in hindsight, hard to locate in advance.

**Marketing application**: Focus resources on one segment before expanding. Depth before breadth.

### Survivorship Bias
**Evidence: Robust.** Reasoning from visible successes while the failures are structurally invisible is a documented statistical error.

**Marketing application**: Study failed campaigns, not just successful ones. The viral hit you're copying had many invisible failures.