Integration of experimental analyses of behavior and neuroscience provides an interpretation of a substantial number of the diverse behavioral deficits observed within the autism spectrum. To that end, the behavioral and neural conditions under which experience changes the environmental guidance of behavior are first described, that is, the conditions under which learning occurs. These findings lead to the conclusion that acquired reinforcers—events that function as reinforcers as the result of individual experience—satisfy the same requirements and ultimately engage the same neural system as unconditioned reinforcers. Acquired reinforcers are critical to the development of complex behavior and some of the behavioral problems seen in autism may be due to these deficits. Specific consequences of these deficits are described—including effects on automatic reinforcement, joint control, and joint attention. Environmental as well as genetic factors can produce neurodevelopmental errors that impair acquired reinforcement and a possible such factor is identified.