A folding protein shapes conformation-dependent solvent environments to which its own intramolecular interactions are sensitive. This context-dependence of the folding process is represented by correlated self-avoiding walks in a cubic lattice. The correlations are shown to account for the nonadditivity of clustering forces and the possible origin of cooperativity in the folding process. The context sensitivity of the sharpness of the canonical ensemble of maximal compact structures is determined. Such results lead to an investigation of the evolutionary consequences of an exogenous modulation of the context sensitivity for natural proteins: biologically disfunctional structural ambiguity or duality may be brought about by an alteration in the environment associated with protein localization.