While Sue's account shows how a negative alignment experience can be offset imagination, she nevertheless hovers on the threshold of a negative by mathematics identity, a characteristic she shares with others in the group. In large part this fragility is due to the almost universal fixed ability beliefs which re perpetuated by the pedagogic practices that surround them and permeate the undergraduate community of practice. Thus Carol, in spite of her robust and critical outlook on mathematics teaching, puts her non-participation down to perceived deficiencies in herself; her beliefs about ability and the nature of mathematics itself all militate to build a self-excluding identity: