The effects which we have studied so far were produced by inanimate objects, posters or displays, advertisements or labels and packings.  The economic psychotechnics of the future will surely study with similar methods the effects of the living commercial agencies.  Experiments will trace the exact effects which the salesman or customer may produce.  But here not even a modest beginning can be discovered, and it would be difficult to mention a single example of experimental research.  The desired psychological influences of the salesman are not quite dissimilar to those of the printed means of propaganda.  Here, too, it is essential to turn the attention of the customer to different points, to awaken a vivid favorable impression, to emphasize the advantages of the goods, to throw full light on them, and finally to influence the will-decision either by convincing arguments or by persuasion and suggestion.  In either case the point is to enhance the impulse to buy and to suppress the opposing ideas.  Yet every one of these factors, when it starts from a man and not from a thing or paper, changes its form.  The influence becomes narrower, it is directed toward a smaller number of persons; but, on the other hand, it gains just by the new possibility of individualization.  The salesman in the store or the commercial traveler adjusts himself to the wishes, reactions, and replies of the buyer.  Above all, when it becomes necessary to direct the attention to the decisive points, the personal agent has the possibility of developing the whole process through a series of stages so that the attention slowly becomes focused on one definite point.  The salesman observes at first only the general limits of the interest of the customer as far as it is indicated by his reactions, but slowly he can find out in this whole field the region of strongest desires.  As soon as he has discovered this narrower region in which the prospects of success seem to be greatest, he can systematically eliminate everything which distracts and scatters the attention.  He can discover whether the psyche of the individual with whom he is dealing can be influenced more strongly by logical arguments or by suggestion, and how far he may calculate on the pleasure instincts, on the excitement of emotions, on the impulse to imitate, on the natural vanity, on the desire for saving, and on the longing for luxury.  In every one of these directions the whole play of human suggestion may be helpful.  The voice may win or destroy confidence, the statement may by its firmness overcome counter-motives or by its uncertainty reinforce them.  Even hand or arm movements by their motor suggestion may focus the desires of the customers, while unskillful, erratic movements may scatter the attention and lead to an inner oscillation of the will to buy.