Dual task protocols are often used to assess the simultaneous performance of two tasks. However, the cognitive and perceptual load factors of empirically studied dual tasks often vary considerably. Thus, the current pilot study systematically investigated the effects of dual task constraints across varying levels of complexity, for three groups of neurologically healthy adults, by closely manipulating cognitive and perceptual load factors. Using a novel methodology, performance was measured during both simple and complex dual tasks that were systematically varied according to stimulus onset asynchrony and set size. The results revealed that set-size and stimulus onset asynchrony factors interact to significantly increase levels of dual task interference. The implications of key findings and potential future applications for this novel dual task protocol are further discussed.