This study was designed to test the impact of two separate variables – (1) thanking philanthropic donors through varying degrees of one-way and two-way interpersonal interaction and (2) informing donors about usage of previous similar gifts – on the philanthropic giving behaviors of two separate populations of female patients who were asked to contribute to a breast cancer research fund via an annual solicitation mailing method. The first portion of the study examines the thanking variable by comparing the annual giving behaviors of a population of female breast cancer donors before and after the donors are thanked through various methods: via either (1) a standard, computer-generated thank-you letter, (2) a voice mail message, (3) a handwr...