This research is designed to improve our understanding of the implicit, unconscious aspects of human thought. It is well known that people learn things without being aware of having learned them. The most compelling examples of this are the natural language we each learned as a child and the complex social- cultural mores of our society. In recent years cognitive psychologists have come to understand a good deal about this process and how it differs from the conscious, explicit learning that takes place in the full light of awareness. The research in this project is designed to explore several novel extensions of this work, particularly how implicit learning emerges in special populations and how it differs from conscious learning. Specifically, the research will examine the degree to which these unconscious processes continue to operate in persons with mild depression and/or anxiety, conditions which are known to interfere with conscious learning processes. The project will also explore the manner in which young children display the capacity for implicit learning, with the expectation that they will be fully capable of learning about highly complex systems so long as they are not consciously trying to learn. An additional important question the research will examine is whether or not these implicit processes change with age as conscious learning is known to. To this end the research will examine children from ages four through twelve. Finally, the project will explore the relationships between implicit learning, conscious learning, and intelligence, as measured by standard IQ tests. The research has implications for a number of important issues in cognitive psychology, particularly the relationship between implicit learning and various complex human skills which people routinely display but which lie largely outside of awareness. Key examples are the development of intuitive judgment, the acquisition of sophisticated skills such as those displayed in medical diagnosis, the development of high level skills in complex games like chess, and the capacity to adjust to cultural and organizational settings.