For several years, my students and I have assisted colleagues at Anti-Persoonsmijnen Ontmijnende Product Ontwikkeling, a Belgian Nongovernmental Organization headquartered in Tanzania, in conducting research designed to evaluate and improve the performance of scent-detecting pouched rats used for humanitarian purposes. Findings indicate that the rats are accurate landmine-detection animals and more sensitive than microscopy, the standard diagnostic in resource-poor areas, in detecting tuberculosis. When used for second-line screening of sputum samples initially evaluated by microscopy, the rats increase new-case detections of tuberculosis by about 40%. Studies have shown that several variables affect their performance, and knowledge of those variables has been used to improve the rats’ performance when they are used operationally. Research has also demonstrated that the rats can detect Salmonella, cigarettes, and people trapped under rubble, but they are not presently used operationally for those purposes. This work illustrates that people who understand behavior and the variables that affect it can act to improve the world in ways outside the boundaries of conventional psychology.