Here’s an interesting quote from William Walker Atkinson:
“The phenomena of Mental Influence bears a striking analogy to that of electrical or magnetic energy. Not only is this so in the phase of wave motion and transmission, but also in the phase of induction, as we shall see presently.
In physical science the term Induction is used to indicate that quality in a manifestation of energy which tends to reproduce in a second object the vibrations manifesting in the first object, without direct contact between the two bodies.
A magnet will induce magnetism in another object removed from it in space. An electrified object will tend to produce similar vibrations in another object by induction, over great spaces. Heat waves travel along the ether, and tend to produce heat vibrations in objects far removed, notably in the case of the sun and the earth. Even sound waves will affect other objects in this way, as in the well known instance of the glass or vase “singing” in response to the musical note sounded afar off. In fact, we see and hear by processes similar to those described.
And in this same manner do the Thought-Waves carry the vibrations of the mind sending them forth to great distances, or lesser ones, tending to set up similar vibrations in the minds of other persons within their field of force. Thus a person feeling a strong degree of anger will pour forth waves of that degree of mental vibration, which, coming in contact with the brains of other persons, tend to set up a similar feeling or emotion and thus cause the person to “feel cross” or “peevish” or even to manifest a similar angry state of mind. We all know how easily a fight is started by a very angry person in a room sending forth violent vibrations.
One has but to remember the instances of mob violence to see how easily the “contagion of hate and anger” spread among people who allow themselves to be influenced. And not only is this true of undesirable emotions and feelings, but also of desirable ones. The influence of a good man who happens to be strong mentally spreads among those around him, influencing them for good.
Orators, actors, preachers and teachers send forth strong mental currents which tend to produce mental conditions on the part of their hearers corresponding to the feeling held by the mind of the speaker. When you remember how this speaker swayed your feelings, or how that actor made you weep with pity, shiver with fear, or laugh with joy, you will see how Mental Induction acts.”