Most would agree that recognition occurs through two distinct processes – one involving the retrieval of a past experience, and the other involving a rough sense that some aspect of present experience is familiar consequent to past experience. Most would agree that these two aspects of recognition involve different bodies of knowledge/brain bases. My students and I have observed priming effects reflecting the two aspects of recognition and have shown that the two effects can be used to study the nature of the knowledge underlying the two aspects. Our goal is to attain general acceptance of our findings. 2. My students and I am exploring how the human perceptual system represents spatial position. Each element of an extrinsic representation is labeled to show its meaning with respect to the external world. Such labeling is not present in an intrinsic representation. Collectively, the elements of such a representation encode relationships among the aspects of the external world to which they correspond. We have obtained evidence that, in assessing distances in a frontal plane, the perceptual system represents spatial position intrinsically. One consequence of the intrinsic representation of position is that the horizontal and vertical aspects of position are not explicitly distinguished. We have obtained evidence that, for the purposes of assessing horizontal and vertical distances, attentional process can re-map the position elements of the representation onto the external world so as to emphasize the horizontal and vertical aspects of position. 3. My students and I are exploring the process by which long term viewpoint-free knowledge of a spatial layout is built from short-term viewpoint-specific knowledge of aspects of that layout. We have been paying particular attention to the role of knowledge at levels of refinement less than the metric level.