1. MacKay, D. M., “Some Perceptual Problems in Terms of Information Flow”: paper read at the Cambridge Conference on Thinking, 1955. A development of the theory was presented at the 15th International Congress of Psychology, August 1957, under the title “The Stability of the Visual World during Voluntary Activity”, and will be published shortly.
2. MacKay, D. M., Nature, 180, 849 (1957).
3. MacKay, D. M., Brit. J. Psychol., 47, 30 (1956).
4. MacKay, D. M., Brit. J. Phil. Sci., 2, 114 (1951); cf. von Holst, E., Brit. J. Animal Behav., 2, 89 (1954).