Robert Kegan's constructive-development theory of adult growth postulates three different ways of knowing (instrumental, socializing, and self-authoring) and suggests that, although individuals develop differently, individual development can never be separated from culture. The potential of the constructive-development perspective on adult development to provide insight on how people's developmental capacities influence how they understand the concept of literacy in their roles as students was examined in a study of 41 adults in 3 adult basic education/English for speakers of other languages programs. Data were gathered through interviews, structured exercises, classroom observations, focus groups, and surveys. The way learners understood what it means to be literate was fundamentally shaped by their different ways of knowing, independent of age and country of origin. Instrumental knowers were oriented largely to the specific and concrete, externally observable behaviors and skills. Socializing knowers saw the need to learn specific skills and behaviors. Self-authoring knowers regarded themselves and other students as additional valid sources of knowledge. It was suggested that literacy practitioners expand their view of literacy instruction, incorporate principles of skills-centered and learner-centered instruction and critical literacy, and utilize the strengths of all perspectives on literacy to optimize the development of all learners. (Contains 58 references.) (MN)