The natural approach was strikingly different from the mainstream approach in the United States in the 1970s and early 1980s, the audio-lingual method. While the audio-lingual method prized drilling and error correction, these things disappeared almost entirely from the natural approach.[4] Terrell and Krashen themselves characterized the natural approach as a "traditional" method[1] and contrasted it with grammar-based approaches, which they characterized as new inventions that had "misled" teachers.[5]