Happy Monday!

Your customers don’t make decisions rationally. They make them fast, using mental shortcuts. Two of the most powerful are social proof (“I’ll do what others are doing”) and scarcity (“I don’t want to miss out”).

Here’s what you’ll find in today’s email:

• Why social proof and scarcity influence engagement

• How to apply them in lifecycle campaigns

• Simple A/B tests to run this week

• Quick hits from across the lifecycle world

☕ Quick favor before we dive in: if you enjoy these newsletters, the easiest way to support me is by clicking the sponsor link below. That’s it, one click makes a big difference.

How to test social proof and scarcity in your next send

Deep Dive

I once tested a pricing email with three plan options. One included a little badge: “Most popular.” That single label drove 18% more clicks on that plan. Why? Because people copy what others choose.

Another time, we added “Your loyalty points expire in 7 days” to a retention flow. Conversions nearly doubled. The difference wasn’t the offer. It was the urgency.

These are not accidents. They’re decision biases at work.

Why these concepts work

• Social proof: Humans are social learners. Psychologists call it “informational social influence.” When we’re unsure, we assume the group knows better, so we copy. In email, showing reviews, popularity badges, or subscriber counts taps into this shortcut. The brain thinks, “If others like me chose this, it must be safe.”

• Scarcity: Scarcity signals value. Research shows limited availability creates urgency because the brain frames it as a potential loss. A countdown timer doesn’t just inform, it triggers the fear of missing out. Scarcity also reduces procrastination — when people feel time or supply slipping away, they act now instead of later.

Social proof in lifecycle marketing

• Abandoned cart emails: Add product reviews or “95% of buyers recommend this.”

• Pricing plans: Highlight the “most popular” or “best value” option.

• Onboarding: Show “4,000 marketers joined last month.”

• Newsletters: Add reader testimonials or subscriber counts.

Scarcity in lifecycle marketing

• Cart recovery: “Your cart will expire in 24 hours.”

• Loyalty programs: “Use your points before they expire.”

• Sales promotions: Countdown timers or “Only 3 left in stock.”

• Win-back emails: “Your account will be deactivated in 7 days.”

How to test these biases

• Social proof A/B test

  • Version A: Standard cart recovery email

  • Version B: Cart recovery email with a product review snippet

• Scarcity A/B test

  • Version A: Promotion email with evergreen offer

  • Version B: Promotion email with a countdown timer or expiring points message

Measure open rates, click-throughs, and unsubscribes to see which framing wins.

Action plan: Apply social proof + scarcity this week

📋 Your 15-minute checklist

• ⬜ Review one cart recovery flow and add a product review or rating.

• ⬜ Pick one pricing or subscription email and add “Most popular” or “Best value.”

• ⬜ Identify one campaign where you can add urgency (“expires soon” or “only 3 left”).

• ⬜ Set up an A/B test with and without these elements.

• ⬜ Record the results and reuse what works.

Closing

Social proof and scarcity are everywhere in marketing. When used thoughtfully, they lift engagement without feeling manipulative. Start with one test this week and see how your audience responds.

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Until next Monday,

Arsalan