Within a day or two an Englishman, whilst discussing telegony, or the influence of a first mating upon the progeny of subsequent pairings, maintained that the widespread belief among dog-breeders in the existence of this influence proved its truth, and my recollection of the argument of my Chinese friend showed me how alike are the causes of belief among all mankind.
Man tends to believe what his fellows believe and act as his fellows act, and this tendency has been erected into an instinct by Trotter, who shows how important the Herd Instinct is to all gregarious animals, including man.[9]
But if suggestion is to be made synonymous with the Herd Instinct it explains too much, and we must seek to narrow its meaning or use another word. It is already used in a somewhat special sense to account for the acceptance of propositions which an ordinary man in his ordinary state of mind would not accept, and especially is it used in relation to abnormal states such as hypnosis and hysteria.
An authoritative and confident manner makes easy the acceptance of suggestion, as every confidence-trick man knows; the writer of advertisements or political articles knows it too, but in the last example we see a new factor. The hardened Big-ender would be impervious to the most imposing suggestions from a Little-endian source, but would accept the saddest nonsense from a journal of his own party. We see here an active desire to accept propositions that accord with a powerful complex, and as complexes become more separated from the influence of reason so this desire increases.
This I shall call 'receptivity', and to the term I shall give a further meaning in the sense not only of desiring to accept propositions but of anticipating or guessing them, of picking up hints as to what is in the minds of the other persons concerned and reflecting them as if they originated in the mind of the receiver.
In some cases of hysteria the patient presents a weak or paralysed limb, and this limb is often so insensitive that pins may be pushed through the skin without any manifestations of pain. This phenomenon, which resembles the insensitive patches that under the name of 'Devil's claws' were found upon witches when witchcraft was fashionable, has been long known as a sign of hysteria. There is now a tendency to ascribe it to suggestibility or, as I should prefer, to receptivity.
In the early stage of the disease some one examines the arm, pricks it, and asks, 'Do you feel that?' It is my experience that the patient sometimes flinches at the first prick, but answers 'No', and until this newly-implanted belief is removed he never flinches again when the limb is pricked.
The question is taken by the patient to mean that the doctor expects that the prick will not be felt—or why should he ask? The hint is accepted and the insensibility established, though its unreal nature is shown by the fact that the patient is not especially disposed to burn or injure the limb, unlike the sufferer from a true loss of sensation, who is always liable to such an accident owing to the lack of the protective sense of pain. I believe that this is the true explanation for many cases, and put it forward as a good example of receptivity.
The insensitiveness is similarly explained by Babinski,[10] who uses a different method of examination. He blindfolds the patient, who must not have been subjected to a previous test, and stimulating him variously in different places asks what he feels. This avoids the suggestion of loss of sensation, and the result is that Babinski finds few examples of such loss in cases where the 'Do you feel that?' method would produce many positive results.
It may also be explained by a dissociation of consciousness, in which the split-off stream deals with the paralysed limb and therefore the main stream of consciousness knows nothing about the prick. The difference between the two theories is not so great as appears, for the control of the supposed loss of sensation, once it is established, finds its home in a split-off stream, and the process I describe is only a stage in the dissociation.