Do timers reduce checkout abandonment?

I'm struggling with high cart abandonment rates and have heard that countdown timers might help motivate customers to complete their purchases. However, I'm skeptical about whether these timers actually work or if they might come across as too aggressive or manipulative. I want to understand the psychology behind countdown timers, their potential impact on conversion rates, and how to implement them effectively without alienating potential customers. What scientific evidence exists to support the use of timers in reducing checkout abandonment?