This paper discusses the cognitive aspects of the programming activity in «colored object programming", a refinement of object oriented programming. The paper first reports works done by cognitive psychologists about object oriented programming ; and browes a number of tools and researches meant for overcoming the difficulties encountered by programmers. The salient features of colored object programming (ex. : visual formalism, simulation capability, declarative programming, ...) are then analysed from a cognitive point of view. Color graphs appear to have distinct advantages for abstracting essential properties and capturing informations that were left implicit in traditional object oriented programming. Besides bringing progresses in information structuring and layering, colored object programming is notably expected to better support of opportunistic programming activities.