Tip or skip? What drives our tipping behavior, with Michael Lynn, PhD

Tipping behavior in the United States is driven primarily by social norms and the desire to avoid disapproval rather than the quality of service provided. While consumers often cite rewarding good service as their primary motivation, empirical data shows that bill size accounts for approximately 70% of tipping variance, with service quality explaining only 4%. Dr. Michael Lynn, a professor of consumer behavior at Cornell University, notes that the rise of digital payment screens has intensified social pressure by forcing customers to make active decisions—a "sin of commission"—rather than simply omitting a tip. Although tipping rates have trended upward linearly over the last 50 years, these norms remain highly variable across different cultures and contexts. Despite inherent biases in tipping, such as disparities based on race and physical attractiveness, no consensus exists on replacing the system, as current alternatives often negatively impact consumer satisfaction.