Subjective measures of unconscious knowledge.

The chapter gives an overview of the use of subjective measures of unconscious knowledge. Unconscious knowledge is knowledge we have, and could very well be using, but we are not aware of. Hence appropriate methods for indicating unconscious knowledge must show that the person (a) has knowledge but (b) does not know that she has it. One way of determining awareness of knowing is by taking confidence ratings after making judgments. If the judgments are above baseline but the person believes they are guessing (guessing criterion) or confidence does not relate to accuracy (zero-correlation criterion) there is evidence of unconscious knowledge. The way these methods can deal with the problem of bias is discussed, as is the use of different types of confidence scales. The guessing and zero-correlation criteria show whether or not the person is aware of knowing the content of the judgment, but not whether the person is aware of what any knowledge was that enabled the judgment. Thus, a distinction is made between judgment and structural knowledge, and it is shown how the conscious status of the latter can also be assessed. Finally, the use of control over the use of knowledge as a subjective measure of judgment knowledge is illustrated. Experiments using artificial grammar learning and a serial reaction time task explore these issues.