In cognitive linguistics, conceptual metaphor, or cognitive metaphor, refers to the understanding of one idea, or conceptual domain, in terms of another. An example of this is the understanding of quantity in terms of directionality (e.g. "the price of peace is rising") or the understanding of time in terms of money (e.g. "I spent time at work today"). A conceptual domain can be any mental organization of human experience. The regularity with which different languages employ the same metaphors, often perceptually based, has led to the hypothesis that the mapping between conceptual domains corresponds to neural mappings in the brain. This theory has gained wide attention, although some researchers question its empirical accuracy. This idea, and a detailed examination of the underlying processes, was first extensively explored by George Lakoff and Mark Johnson in their work Metaphors We Live By in 1980. Since then, the field of metaphor studies within the larger discipline of cognitive linguistics has increasingly developed, with several annual academic conferences, scholarly societies, and research labs contributing to the subject area. Some researchers, such as Gerard Steen, have worked to develop empirical investigative tools for metaphor research, including the Metaphor Identification Procedure, or MIP. In Psychology, Raymond W. Gibbs, Jr., has investigated conceptual metaphor and embodiment through a number of psychological experiments. Other cognitive scientists, for example Gilles Fauconnier, study subjects similar to conceptual metaphor under the labels "analogy", "conceptual blending" and "ideasthesia". Conceptual metaphors are useful for understanding complex ideas in simple terms and therefore are frequently used to give insight to abstract theories and models. For example, the conceptual metaphor of viewing communication as a conduit is one large theory explained with a metaphor. So not only is our everyday communication shaped by the language of conceptual metaphors, but so is the very way we understand scholarly theories. These metaphors are prevalent in communication and we do not just use them in language; we actually perceive and act in accordance with the metaphors. Criticism and Perspectives on Metaphor Historical In the Western philosophical tradition, Aristotle is often situated as the first commentator on the nature of metaphor, writing in the Poetics, "A 'metaphorical term' involves the transferred use of a term that properly belongs to something else," and elsewhere in the Rhetoric he says that metaphors make learning pleasant; "To learn easily is naturally pleasant to all people, and words signify something, so whatever words