The effect of server posture (standing vs. squatting) on the size of tip left by restaurant customers was examined in two naturalistic experiments. In these studies, squatting down next to the tables increased servers' tips from those tables. Both the practical implications of this effect and its similarity to other nonverbal effects on tipping are discussed.
Lynn, M., & Mynier, K. (1993). Effect of server posture on restaurant tipping [Electronic version]. Retrieved [insert date], from Cornell University, School of Hospitality Administration site: http://scholarship.sha.cornell.edu/articles/41