academic and social norms, which thwart the students' abilities to develop independently and think creatively. The hidden curriculum has been further explored by a number of educators. Starting with Pedagogy of the Oppressed, published in 1972, through the late 1990s, Brazilian educator Paulo Freire explored various effects of presumptive teaching on students, schools, and society as a whole. Freire's explorations were in sync with those of John Holt and Ivan Illich, each of whom were quickly identified as radical educators. Other theorists who have identified the nature of hidden curricula and hidden agendas include Neil Postman, Paul Goodman, Joel Spring, John Taylor Gatto, and others. More recent definitions have been given by Roland Meighan ("A Sociology of Education," 1981) and Michael Haralambos ("Sociology: Themes and Perspectives," 1991). Meighan wrote, "The hidden curriculum is taught by the school, not by any teacher...something is coming across to the pupils which may never be spoken in the English lesson or prayed about in assembly. They are picking-up an approach to living and an attitude to learning." Haralambos wrote, "The hidden curriculum consists of those things pupils learn through the experience of attending school rather than the stated educational objectives of such institutions." Further, educational critics Henry Giroux, bell hooks, and Jonathan Kozol have also examined the effects of the hidden curriculum. Additionally, developmental psychologist Robert Kegan addressed the hidden curriculum of everyday life in his 1994 book In Over Our Heads, which focused on the relation between cognitive development and the "cognitive demands" of cultural expectations. Professor of communication Joseph Turow, in his 2017 book The Aisles Have Eyes, used the concept to describe acculturation to massive personal data collection; he wrote, "The very activities that dismay privacy and anti-discrimination advocates are already beginning to become everyday habits in American lives, and part of Americans' cultural routines. Retailing is at the leading edge of a new hidden curriculum for American society—teaching people what they have to give up in order to get along in the twenty-first century." See also Curriculum Curriculum studies Dumbing Us Down Educational assessment Educational inequality Ideology and Ideological State Apparatuses Tacit knowledge Youth voice in education References Curricula Philosophy of education Critical pedagogy