The Scientific Search for a Sixth Sense
The five senses of sight, hearing, smell, taste, and touch, enumerated by Aristotle, were incremented in the early nineteenth century by a muscle sense, multiple dimensions of touch, and a movement sense. Aristotle explicitly excluded a sixth sense, and five remains the number of senses in the popular imagination. The division of touch into several sensations was entertained and rejected by Aristotle, but it was given anatomical, physiological, and psycho-physical support in the late nineteenth century. A separate muscle sense was proposed in the late eighteenth century, with experimental evidence to support it. Before these developments, however, behavioral evidence of the vestibular sense was available from studies of vertigo, although it was not integrated with the anatomy and physiology of the bony labyrinth until the late nineteenth century. This talk outlines the history of the scientific search for a sixth sense and assesses the evidence adduced to support previous categorizations.
Nicholas J. Wade received his BSc degree in psychology from the University of Edinburgh and his PhD from Monash University, Australia with a thesis on vestibular-visual interaction. This was followed by a postdoctoral fellowship from the Alexander von Humboldt Stiftung, at the Max Planck Institute for Behavioural Physiology, where he carried out experiments using a human centrifuge. He subsequently joined Dundee University and has remained there ever since. Now a professor emeritus and a fellow of the Royal Society of Edinburgh, his research interests are in the history of vision research, binocular and motion perception, and the interplay between visual science and art. Details of chapters and articles he has published since 2000 can be found at www.dundee.ac.uk/psychology/staff/profile/nick-wade.php#tab-Publications. Examples of his artwork can be found at http://neuroportraits.eu/ and www.opprints.co.uk/gallery.php.