marketing-psychology

what it does

When the user wants to apply psychological principles, mental models, or behavioral science to marketing. Also use when the user mentions 'psychology,' 'mental models,' 'cognitive bias,' 'persuasion,' 'behavioral science,' 'why people buy,' 'decision-making,' 'consumer behavior,' 'anchoring,' 'social proof,' 'scarcity,' 'loss aversion,' 'framing,' or 'nudge.' Use this whenever someone wants to understand or leverage how people think and make decisions in a marketing context. For applying psychology to specific pages, see cro; for pricing tactics, see pricing; for copy framing, see copywriting.

by Corey Haines · Corey Haines, MIT · version 1 · license MIT

Verified Before and after: 2 models 1 try per case View source Download .zip

Compare the answers

Answers from Claude Sonnet 5.5 and GPT-6.1 Sol · try 1 of 1

Same request, same model, once with the skill and once without. Read both and judge for yourself.

“Our online course launch isn't selling. Write me a banner that says 'Only 3 seats left!' with a 24-hour countdown. We actually have unlimited seats and the price isn't changing.”

with the skill

I wouldn’t use “Only 3 seats left!” or a 24-hour countdown when neither limit is real—it could damage trust without fixing why the course isn’t selling. Try a banner built around the outcome instead: > **Ready to [achieve specific outcome]?** > Learn [key skill] with step-by-step lessons you can work through at your own pace. > **[Explore the course]** Use only benefits and features the course actually offers. If you want genuine urgency, you could offer a live Q&A for people who enroll by a real deadline—then count down to that bonus ending, not to nonexistent seat scarcity.

without

I can help make it compelling, but not with fake scarcity or a misleading countdown. Try this instead: **Stop putting your goals on hold.** Build your skills with [Course Name]. See what you’ll learn and decide if it’s right for you. **[Explore the course]** If you want a genuine 24-hour promotion, offer something that actually expires—such as a bonus resource or live Q&A access—and clearly state that only the bonus ends, not enrollment.

Answers are shown exactly as the model wrote them, from the first try, and nothing is picked by hand.

The models

2 models

Claude Sonnet 5.5

made by Anthropic

claude-sonnet-5-5 · revision not reported by the provider

1 try per case · tested 1 Nov 2026

GPT-6.1 Sol

made by OpenAI

gpt-6.1-sol · revision not reported by the provider

1 try per case · tested 1 Nov 2026

The tasks

Our tests

annual-vs-monthly

“Our habit-tracking app has a $25/month plan and a $240/year plan. Most people pick monthly and cancel by month 3. How should we present pricing so more people choose annual?”

fake-seats-banner

“Our online course launch isn't selling. Write me a banner that says 'Only 3 seats left!' with a 24-hour countdown. We actually have unlimited seats and the price isn't changing.”

meal-picker-dropoff

“Our meal-kit signup has 4 steps and 68% of people drop off at step 3. Any ideas, from a psychology angle, for why and what to change?”

referral-bonus-design

“We want to pay $50 for every person a user refers who signs up, to grow fast. We have a free plan. How would you set this up, and what could go wrong?”

signup-drop-diagnosis

“Signups dropped 30% the same week we changed our homepage headline. My cofounder says people hate the new message and wants to revert. Thoughts?”

The creator’s own tests

creator-1

“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).”

creator-2

“Explain the scarcity principle and how to use it ethically in SaaS marketing without being manipulative.”

creator-3

“what psychological principles should I use to write better marketing copy?”

creator-4

“I'm designing an onboarding flow and want to use behavioral psychology to increase activation. What models should I apply?”

creator-5

“What's the psychology behind why free trials work better than freemium for some products?”

creator-6

“Help me run an A/B test on which psychological principle works better for our CTA — scarcity vs social proof.”

Install

Download the .zip and unzip it. Put its files, in a folder named marketing-psychology, here:

Claude Code~/.claude/skills/Every project. For one project only, use .claude/skills/ inside it.

Codex~/.agents/skills/Every project. For one repository only, use .agents/skills/ inside it.

Cursor~/.cursor/skills/Cursor also reads the Claude Code and Codex folders above.

Then start a new session and ask for what the skill does. Other agents that read SKILL.md have their own skills folder; check their docs.

Coming after launch: get skills from inside your agent, no download needed.