Sub-modalities - the presupposition underlying this concept which arose in the field of neuro-linguistic programming (NLP), and particularly the work of its co-creator Richard Bandler, is that human beings code internal experiences -- their mental representations -- using aspects of their different senses, or 'modalities'. See Bandler's Using Your Brain for a Change (Real People Press, 1985). Sub-modalities refers to the subdivisions within any one representation system. For example, in visual: brightness, degree of colour (saturation), size, distance, sharpness, focus, and so on; in auditory: loudness, pitch, tonal range, distance, clarity, timbre, and so on. Ordinarily, you would get these by asking, "This image - is it bright, or dim? Coloured or black and white? How much colour? Is it big or small? Is it near or far? In focus, or out of focus? etc" And, "This sound - is it loud or soft? Is it high pitched or low pitched? Does it have a range? Is it near or far? Is it one point source or spread out? Is it clear or muffled? Is it a pure tone or ... " The interesting discovery is that voluntary change of these on the part of the subject alters the concommitant 'feeling' response, paving the way for a number of change techniques based on deliberately changing internal representations. Eric Robbie made the discovery that specific sub-modalities could be noted through subtle body language cues, eg tilting back of the head when looking at a panoramic mental image. The interesting question of the last few years is: do the commonly expressed distinctions or sub-modalities map to specific areas of the brain, as delineated by Semir Seki (see for example, his Inner Vision: an Exploration of Art and Brain, OUP, 2000).