One of my favorite persuasion tactics is reciprocity. When we receive something from someone, whether it’s a gift or something as small as a compliment, we feel grateful. Our gratefulness makes us want to reciprocate and give them something in return. This is the power of reciprocity in action. 

We see this implemented in marketing. A brand may offer a special discount on first purchases, which may compel many first-time visitors to make a purchase. Some may offer a discount to people who sign up, compelling many shoppers to register on the site instead of checking out as guests.

When shoppers see that a certain item they like is running low in stock, they feel compelled to make the purchase right away instead of saving it for later. In a way, it goes hand in hand with the urgency principle. 

When a certain item is rare, we tend to have this perception that it is more valuable. On the other hand, we tend to lose interest in something that everyone else can have access to. In other words, exclusivity is what we crave as humans. This is what the scarcity principle is all about.