Autonomic mechanisms in spider phobia reactions

A strong fear of spiders is classified as a Specific Phobia, Animal Type (American Psychiatric Association, 1994). A number of theories have been suggested as to how this fear develops and how it is expressed in the physiological realm. This review addresses these issues. Systematic desensitisation has been the treatment of choice for phobias for some time. Issues concerning group administration of this procedure are discussed, as are a number of studies into physiological reflections of treatment success. Respiratory sinus arrhythmia (RSA) has been widely accepted as a measure of vagal tone in psychophysiological studies. This review outlines a current theory that explores the physiology of RSA and why it does not always respond in concert with heart rate. The potential implications of the RSA measure for psychophysiology and psychology as a whole are also discussed, as are a number of different variables which can affect the quantification of the RSA measure. The review concludes with an investigation into the possibility of using the RSA measure to specify the nature of the physiological mechanisms of specific phobia, both in terms of the strength of phobic response and also in terms of modifications due to a treatment program.