The term "cognitive tool" is metaphorical, not literal. Metaphorical thinking is a form of cognition that is common among adults and is itself one kind cognitive tool. Just as the kinds of tools we use for work, like carpenter's tools or office tools, are extensions of our physical attributes, so cognitive tools are extensions of our native ability to perceive reality. If a hammer is an extension of the natural capacity of the hand, then an analogy (one cognitive tool) is an extension of the organs of perception.
Cognitive tools for adults are not necessarily the product of a particular kind of teaching. Adults acquire cognitive tools through experience and practice. Russian psychologist Lev Vygotsky suggests three general categories of experience that provide particular kinds of cognitive tools: oral language, literacy and theoretical thinking. Oral language embeds adults in culture, and the use of oral language provides users with an appreciation of main ideas, the ability to think of things as possible (imagination), metaphor, story, word-evoked images, binary opposites, humor and linguistic patterns. Literacy develops the "imaginative eye," an appreciation for context, a sense of wonder and a desire for meaning. Theoretical thinking develops a sense of agency, the grasp of meta-narratives and the mastery of general abstractions.
Dr. Cassandra Volpe Horii of Harvard University has written on the development of cognitive tools in adult learning from the perspective of the difference between the "novice" and the "expert." Rather than define these "tools" as given characteristics, she describes a continuum similar to what we might see in the development from an apprentice to a master in certain crafts. Examples of novice to expert learning characteristic differences are: "little prior subject knowledge" versus "extensive prior knowledge," "lack of awareness of their misconceptions" versus "ability to correct their misconceptions," "knowledge tends to be organized according to surface features" versus "knowledge is organized according to deeper concepts," and "steps may seem arbitrary or rote" versus "automatic problem-solving process makes it easy to skip steps and often involves big-picture thinking."
Dr. Catherine Hansman at Cleveland State University contends that adult acquisition of cognitive tools is considerably accelerated by learning in the actual context where the learning will be applied. Her work also commends the apprenticeship model of adult learning. Situated learning, the term she uses for learning in the context of actual application, in a community of practitioners provides what she calls "cognitive apprenticeship," or the development of cognitive tools through a process that does not draw a distinct line between learning and practice.