The explanation of the success of suggestion in particular cases is to be sought in the emotional state of the subject. When I was the victim, as described above, my readiness to believe arose from my being accustomed to nocturnal interruptions when my patients were in trouble and also from my reliance on the hospital staff, my emotional state being one of expectation and confidence. If to these influences are added stronger emotional forces, such as wonder or terror, acceptance of suggestion is still easier, and when people assembled together are swayed by these feelings the Herd Instinct reaches its full strength and we have the ingredients for the manufacture of a collective delusion. There are many examples of strange and supernatural occurrences vouched for by masses of observers, and I see no reason to doubt the good faith of the historians. We all know how infectious is emotion and how hard it is for one man to remain unmoved when around him are others all under the influence of some excitement, and man always insists on finding reasons for his feelings or objects for his emotions. When wonder or terror are roused by the operation of the Herd Instinct, the individual, not knowing their origin, projects them externally and seeks an object for them. He is now ready to see or hear anything that will fit his emotions, and when an object is suggested he will speedily accept its existence as a reality.
I will give some further examples of suggestion in varying degrees of strength. During the arrival of recently wounded men at a hospital in France, I was in a ward with two eminent members of my profession and another medical officer. As one man seemed bad the sister asked me to see him at once; his left arm was paralysed, and he had a wound on the head where in the brain beneath lies the 'motor area' of the left arm. Looking at the wound, which was obscured by hair and blood, I said, 'That's pulsating'; the two consultants and the other officer agreed with my observation, and appropriate treatment was recommended. The importance of pulsation lies in the fact that it is a sign of the exposure of brain substance, which pulsates strongly, and in this case it signified the presence of a hole in the skull which allowed the pulsation to appear; but in the operating theatre shortly afterwards the skull was found intact, and therefore pulsation had not been present.
How did this joint error of observation arise? The combination of a gunshot wound of the head with a paralysed limb may occur in connection with a hole in the skull, and such penetrating wounds were common before the introduction of helmets. My unconscious had worked out the probabilities and led me to expect the signs of penetration; deceiving myself, by my confident manner I imposed my belief upon my colleagues, who had, I may assume, placed unjustified confidence in my reliability as an observer; and we all saw that which was not.
Another example shows how ghost stories arise: A man related to me how at the age of sixteen he was sleeping with his brother, and woke up to see a ghostly face on the wall. So far we have an ordinary half-awake hallucinatory condition, which is not uncommon; but the lad became terrified and tried to cover his head to hide the sight, when the brother woke up, and, being told of the face, promptly saw it too. The brother's evidence is strongly corroborative, not of the presence of a ghost, but of the power of suggestion when the way is prepared by strong emotion. It may be remarked that the man was one of those nervous people who fear the dark or being alone; seeing a ghost was not the cause of his condition, but resulted from the inculcation of a belief in ghosts in a person predisposed to fall a prey to his own unconscious.
The next example is a well-worn tale which has been quoted by Frank Podmore, W. H. Myers, Sir William Barrett, and probably many others. I take it from pages 62 and 63 of Human Personality, vol. i.[12]
It (the account) was given by Mr. Charles Lett on December 3, 1885, and reads as follows:—
'On the 5th of April, 1873, my wife's father, Captain Towns, died at his residence, Cranbrook, Rose Bay, near Sydney, New South Wales. About six weeks after his death my wife had occasion, one evening about nine o'clock, to go to one of the bedrooms in the house. She was accompanied by a young lady, Miss Britton, and as they entered the room—the gas was burning all the time—they were amazed to see, reflected as it were upon the polished surface of the wardrobe, the image of Captain Towns. It was barely half-figure, the head, shoulders, and part of the arms only showing—in fact it was like an ordinary medallion portrait, but life-size. The face appeared wan and pale, as it did before his death; he wore a kind of grey flannel jacket, in which he had been accustomed to sleep. Surprised and half alarmed at what they saw, their first idea was that a portrait had been hung in the room, and that what they saw was its reflection, but there was no picture of the kind.
'Whilst they were looking and wondering, my wife's sister, Miss Towns, came into the room, and before either of the others had time to speak, she exclaimed, "Good gracious! Do you see Papa?" One of the housemaids happened to be passing downstairs at the moment and she was called in, and asked if she saw anything, and her reply was "Oh, Miss: the master." Graham—Captain Towns' old body-servant—was then sent for, and he also exclaimed, "Oh, Lord save us! Mrs. Lett, it's the Captain!" The butler was called, and then Mrs. Crane, my wife's nurse, and they both said what they saw. Finally Mrs. Towns was sent for, and, seeing the apparition, she advanced towards it ... as she passed her hand over the panel of the wardrobe the figure gradually faded away, and never again appeared.
'These are the facts of the case, and they admit of no deceit; no kind of intimation was given to any of the witnesses; the same question was put to each one as they came into the room, and the reply was given without hesitation by each.
'Mrs. Lett is positive that the recognition of the appearance on the part of each of the later witnesses was independent, and not due to any suggestion from the persons already in the room.'
Then follows a statement by two of the witnesses that this account is correct.
In the lapse of twelve years between the incident and its narration a story of this nature would have been re-told many times, and we know what happens under such conditions. As the tale is given, however, it reveals more than the narrator thinks it does.
Most interesting is the denial of suggestion when we have present all the factors necessary for suggestion of the most powerful kind. Picture Miss Towns coming into the room whilst the first two were 'looking and wondering' (and not in silence, we may be sure, in spite of the words 'before either of the others had time to speak', which are interpolated to strengthen the story); she straightway experiences the same emotion as do the others and sees what they see. Now we have three emotional people, and as each new witness is brought along the emotion increases till it would require a very self-possessed and sceptical person to resist its influence. The butler and the nurse simply had to see the ghost, though the account is a little ambiguous at that point.