Dieter Vaitl*
Clinical and Physiological Psychology, University of Giessen, Otto-Behaghel-Strasse 10, D-35394 Giessen, Germany
Abstract
During the last two decades, research on interoception has experienced a surprising renaissance. New experimental approaches and methods have revealed much about the processing of afferent signals from the inner organs of the body, and have allowed more accurate descriptions of these processes, as well as a more accurate determination of their functional significance in the experience and behavior of humans. Besides neuromuscular, respiratory, and gastrointestinal interoceptive processes, the cardiovascular afferent influences are now known to be very important. Invariably, the central questions concern sensitivity to signals from the body, factors which may influence judgment of perception, and the degree to which conventional hypotheses regarding the interoceptive capabilities of humans may require revision. Findings from general psychological and clinical studies have shown that humans may attain remarkable levels of interoceptive performance. On the other hand, they also show how deep the chasm is between visceral processes and perception, and between that which is perceived and the reports thereof. Only interdisciplinary approaches to these complex processes promise success.
Keywords: Visceroception; Cardiac perception; Respiration; Gastro-intestinal system; Endocrine system; EEG.
- Definition of terms
Interoception is a general concept which includes two different forms of perception: proprioception and visceroception. In proprioception, signals from the body are received primarily from the skin and the musculoskeletal apparatus (joints, tendons, muscles). Visceroception (Latin: viscera = inner organs) is the term used to describe signals arising from the inner organs.
Physiologists and psychologists have investigated the influence of signals from the bodily interior on experience and behavior for more than a hundred years. Thirst, hunger, desire, and pain belong to the fundamental forms of experience in animals and humans. The activity of visceral organs is experienced directly when they relinquish their anonymity to inflict pain on the individual. However, as long as these organs remain silent, there is no particular reason to pay attention to them. Indeed, this may be the reason why this form of perception has been largely ignored, never receiving the attention in research that its biological importance would seem to warrant. The debate regarding the significance of interoception is already quite an old one. Two developmental lines can be differentiated, the beginnings of which lie in the preceding century: psychophysics and the psychology of emotion. The well-known psychophysical experiments by Fechner (1860) pursue the question as to whetherand to what degree interoceptive signals can be perceived. Similarly, Boring (19 15a,b) performed differential psychological experiments, in which he searched for indicators of the individual’s capability to perceive visceral processes.
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