Synchronous and desynchronous changes during fear reduction.

The purpose of this experiment, carried out on 27 subjects with intense and circumscribed fears, was to test one main hypothesis and several subsidiary predictions. The prediction that a high-demand in vivo treatment condition produces desynchronous changes and a low-demand treatment condition synchronous changes, was supported by some inter-session findings but not by the intra-session findings. The clear linear relation between heart-rate and reported fear was confirmed, as was the rapid habituation of the heart-rate response to phobic stimulation.The fear-reactions and fear-reductions of psychiatric and non-psychiatric were indistinguishable. High heart-rate responders and low heart-rate responders showed similar patterns of improvement. The constrained laboratory ‘treatment’ procedure used in the experiment produced large and rapid reductions in fear.