In the same way, the assurance of promotion, and the fact that the worker sees those of his own trade promoted, and knows it is to the advantage of the management, as well as to his advantage, that he also be promoted,--this also maintains interest in the work. THIS INTEREST EXTENDS TO THE WORK OF OTHERS.--The interest is extended to the work of others, not only by the interrelated bonuses, but also by the fact that every man is expected to train up a man to take his place, before he is promoted. CLOSE RELATIONSHIP OF ALL PARTS OF SCIENTIFIC MANAGEMENT HOLDS INTEREST.--The attention of the entire organization, as well as of the individual worker, is held by Scientific Management and its teaching, because all parts of Scientific Management are related, and because Scientific Management provides for scientifically directed progression. Every member of the organization knows that the standards which are taught by Scientific Management contain the permanent elements of past successes, and provide for such development as will assure progress and success in the future. Every member of the organization realizes that upon his individual cooeperation depends, in part, the stability of Scientific Management, because it is based on universal cooeperation. This provides an intensity and a continuity of interest that would still hold, even though some particular element might lose its interest. THIS RELATIONSHIP ALSO PROVIDES FOR ASSOCIATIONS.--The close relationship of all parts of Scientific Management provides that all ideas are associated, and are so closely connected that they can act as a single group, or any selected number of elements can act as a group. SCIENTIFIC MANAGEMENT ESTABLISHES BRAIN GROUPS THAT HABITUALLY ACT IN UNISON.--Professor Read, in describing the general mental principle of association says, "When any number of brain cells have been in action together, they form a habit of acting in unison, so that when one of them is stimulated in a certain way, the others will also behave in the way established by the habit."[31] This working of the brain is recognized in grouping of motions, such as "playing for position."[32] Scientific Management provides the groups, the habit, and the stimulus, all according to standard methods, so that the result is largely predictable. METHOD OF ESTABLISHING SUCH GROUPS IN THE WORKER'S BRAIN.--The standard elements of Scientific Management afford units for such groups. Eventually, with the use of such elements in instruction cards, would be formed, in the minds of the worker, such groups of units as would aid in foreseeing results, just as the foreseeing of groups of moves aids the expert chess or checker player. The size and number of such groups would indicate the skill of the worker. That such skill may be gained quickest, Scientific Management synthesizes the units into definite groups, and teaches these to the workers as groups.