Buddhist Abhidharma expanded and developed this basic model and Yogācāra responded by rearranging these into their own schema which had three novel forms of consciousness. The sixth consciousness, "mano-vijñāna," was seen as the surveyor of the content of the five senses as well as of mental content like thoughts and ideas. The seventh consciousness developed from the early Buddhist concept of "manas," and was seen as the defiled mentation ("kliṣṭa-manas") which is obsessed with notions of "self". According to Paul Williams, this consciousness "takes the substratum consciousness as its object and mistakenly considers the substratum consciousness to be a true Self."