Behavioral theories completely reject the idea of genetics having an influence on human behavior. Psychology in its modern form, on the other hand, accepts genetic influence on human behavior as a fact. One of the most prominent social psychologists, Kurt Lewin, tried to resolve the limitation of behavioral theories by giving his famous equation: behavior is a function of the person (genetic nature) and the environment. Behavioral theories lack one of the vital factors in Lewin's equation, and cannot completely describe human behavior.
Psychologists that developed behavioral theories backed these theories on experiments containing stimuli that are not easily relatable. In these experiments artificial environments are constructed to condition subjects to associating these normally unrelatable stimuli, such as food and electric shock. The psychologists then generalized their results to all sets of stimuli, no matter how easily the relationships between these stimuli are made. The limitation in this case is that such a generalization cannot scientifically follow such experiments. In short, this generalization by behavioral theories is flawed.
Behavioral theories also ignore the cognitive aspects of human psychology. Because behavioral theories explain everything in terms of the "outside" (behavior) and discard the "inside" (mental processes, genetic influences, emotions and so on), ideas like memory and though processes cannot enter the behavioral explanations of human actions. However, much research in psychometrics, the field of psychological measurement, has shown that these mental aspects predict much of human behavior. One example is how personality tests correlate to human decisions such as job and mate selection. In this respect, behavioral theories see humans as no different creatures than animals: mental processes are not important.
Behavioral theories are useless in explaining mental problems. Because behavioral theories treat the human mind as a "black box," they have no place in explaining diseases that are associated with abnormal thought processes such as schizophrenia and pedophilia. It then follows that behavioral theories cannot assist those with mental diseases in their treatment processes.