This chapter focuses on the prediction of consumer behavior with such implicit reaction time measures. It provides a very brief overview of the use of indirect measures in consumer research and of the most prominent implicit reaction time measures in current use. Everyday experiences and scientific evidence from different lines of research converge in the idea that in many instances, in addition to reflective intentions, uncontrolled processes influence consumer behavior as well. The effects of both reduced cognitive capacity and processing time differ in at least two important ways from those of reduced self-regulatory resources. When cognitive capacity is largely occupied by other things or if the time to deliberate is simply not available, there is no way to work around it, because higher order reasoning strictly depends on these resources, and the ability to stretch these resources by willpower is limited.