The Behavioral Assessment and Research System (BARS) is a computer-based testing system designed to assess neurobehavioral function in humans. It was developed to provide a series or battery of neurobehavioral tests optimized for the detection of neurotoxicity in non-mainstream human populations, specifically people with limited education or literacy. Key to meeting this goal were simply-stated instructions divided into an elemental series of steps, a 9BUTTON response unit to replace the computer keyboard for responding, and spoken instructions. Modifications all underwent serial testing in target populations to successively hone the changes to be more effective. A similar process was followed when developing adjustable parameters, test reliability assessments, and when implementing these tests with populations from different cultural groups and children. The principles and experiences that guided the development of BARS should inform the development of future testing systems to ensure that the new tests can be used with non-mainstream populations, which may be increasingly subject to neurotoxic exposures.