Transactional analysis was founded by Eric Berne in the late 1950s. It is effectively a language within a language that helps understand communication patterns between people. There are three ego states - Parent, Adult, and Child - that represent different thought and behavior patterns. Effective communication occurs through complementary transactions when different ego states respond appropriately to each other. Ineffective communication happens through crossed or ulterior transactions when unexpected responses activate inappropriate ego states. Modern transactional analysis expanded the model to seven elements to better analyze interpersonal dynamics.