Dream Content and Waking Cognition
Findings from the study of dream content not only suggest links with the neural network for dreaming, but also with waking cognition. In particular, the continuity principle provides the same kind of strong connection between dreaming and waking cognition that has been demonstrated by the neuropsychological and developmental evidence presented earlier in this chapter. This continuity leads to the hypothesis that both dreaming and waking cognition are dealing with the same psychological issues to a large extent. This hypothesis provides the basis for linking a neurocognitive model of dreams with what is known about waking cognition.
However, as shown by the evidence concerning the repetition principle in the previous section, the continuity principle does not operate entirely in terms of current personal interests and concerns. Dream content is also continuous in varying degrees for different individuals with past waking concerns. Discrepancies between current waking concerns and current dream content, such as dreaming about painful events that are no longer thought about in waking life, could be used to see how the continuity and repetition principles interact with each other to shape dream content.
The starting point for adding a cognitive dimension to the model is the concept of a "conceptual system," or system of schemas and scripts, which is the organizational basis for all human knowledge and beliefs. Most of this system is thought to be unconscious, in the sense of being outside of conscious awareness, but some of it can become conscious as well. It consists of both experientially based and figurative concepts, both of which are processed and understood equally fast and well according to experimental studies (Gibbs, 1994; Gibbs, 1999). The conceptual system builds on three types of experiential categories that are based upon bodily sensations and interactions with the world: basic level, spatial relations, and sensorimotor (Lakoff & Johnson, 1999).
Basic-level categories arise through the interaction of inherited neural structures with patterns of stimuli from the environment. They reflect distinctions among types of animals, such as cows, horses, and goats, or types of social interactions, such as friendly and aggressive interactions, or types of actions, such as walking and running. Basic-level categories are most directly distinguished from other categories by the fact that a single mental image can represent an entire category, such as a "dog" or a "cat," a "boat" or a "car" (Murphy & Lassaline, 1997). In addition to the large number of basic-level categories, there are also spatial relations categories that are experiential in nature, such as "up," "down," "in front of," and "in back of." Comparative linguistic studies show that "there is a relatively small collection of primitive image schemas that structure systems of spatial relations in the world's languages" (Lakoff & Johnson, 1999, p. 35). Finally, there are sensorimotor categories that are based on direct experience of such varied qualities as temperature, motion, and touch.
Dreams are thought of as highly "symbolic" in many different cultures, including Western civilization, but the findings from content analysis suggest that dreams may consist primarily of constructions arising from experiential categories. Based on his reading of thousands of dreams collected from children, teenagers, and adults in the sleep laboratory, Foulkes (1985) concludes that most dreams are "simulations" of real-world experiences. Young adult dreamers are often shopping, playing sports, visiting with their friends, arguing with their parents, worrying about the faithfulness of their lovers, or feeling tempted to be unfaithful themselves. The content of young children's dreams is usually even more realistic.
