Cultivation is often referenced as one of the most influential traditions in the history of media research. The original purpose of cultivation studies was to investigate if media portrayals of social reality would bias people's perceptions of the real world and, thus, gradually alter society's norms, values, and customs. The field was quickly met with substantial criticisms, however, especially with regard to its testing procedures. Cultivation studies typically only reported correlations between measurements of television viewing and people's reality perceptions, and critics noted that this type of evidence was insufficient to conclude that television was, in fact, biasing people's belief systems. In response, cultivation scholars started to research the psychological processes that would explain their correlations and, thus, add validity to their theoretical claims. The processing models resulting from these efforts have had an enormous influence on the cultivation literature over the past three decades. However, they have also been subject to many criticisms themselves and, as a result, the viability of the cultivation research remains a topic of controversy.