A review of extent business ethics research uncovered well over 200 published articles that investigated the role of job functions within a business organization as an explanatory factor of ethical or unethical behavior. While an important body of work, ethical breaches are often found to cut across job functions and involve multiple disciplines embedded in a business organization. This research seeks to explore a crossfunctional explanation for ethical reasoning by using an instrument new to business ethics research, the Wason selection (...) task, but well-grounded and validated in cognitive research and evolutionary psychology, to assess an individual's ability to detect rule-based social contract violations. A sample of 276 full-time business practitioners, enrolled in part-time M.B.A. programs, from the accounting, finance, information technology, marketing, supply chain, and human resource management job functions were compared on their ability to detect rule violators across a series of production scenarios in the Wason selection task. Rates of cheater detection were calculated to determine if substantive differences existed across job functions. This was followed by a series of pairwise comparisons of percentages of cheater detection across the job functions using z-tests for assessing statistical significance. The data analysis showed differences in cheater detection, with most of the variance due to the marketing job function group. Insights from this study for scholars, educators, and practitioners in the business ethics field are discussed. (shrink)