The Trained Memory | Page 6

one to tend to recall the thought of the other._
This is the Associative Law of Contiguity considered from the standpoint of recall. The points of contiguity are different for different individuals. Similarities and nearnesses will awaken all sorts of associated groups of ideas in one person that are not at all excitable in the same way in another whose experiences have been different.
Law III. _The greater the frequency and intensity of any given experience, the greater the ease and likelihood of its reproduction and recall._
[Sidenote: Laws of Habit and Intensity]
This explains why certain groups in any complex are more readily recalled than others--why some leap forth unbidden, why some come next and before others, why some arrive but tardily or not at all.
This is how the associative Laws of Habit and Intensity affect the power of recall.
* * * * *
[Sidenote: Applications to Advertising]
There is no department of business to which the application of these Laws of Recall is so apparent as the department of advertising. The most carefully worded and best-illustrated advertisement may fail to pay its cost unless the underlying principles of choice of position, selection of medium and size of space are understood. The advertisers in metropolitan newspapers and magazines of large circulation are the ones who have most at stake. But whatever the field to be reached, it is well to bear in mind certain facts based on the Laws of Recall that have been established by psychological experiment.
Most advertisers have a general idea that certain relative positions on the newspaper or magazine page are to be preferred over others, but they have no conception of the real differences in relative recall value. When the great cost of space in large publications is considered the financial value of such knowledge is evident.
By a great number of tests the relative recall value of every part of the newspaper page has been approximately determined. It has been found, for example, that a given space at the upper right-hand corner of the page has more than twice the value of the same amount of space in the lower left-hand corner.
[Sidenote: Effect of Repetitions]
Many advertisers adopt the policy of repeating full-page advertisements at long intervals instead of advertising in a small way continually. Laboratory tests have shown, on the contrary, that a quarter-page advertisement appearing in four successive issues of a newspaper is fifty per cent more effective than a full-page advertisement appearing only once. It does not follow, however, that an eighth-page advertisement repeated eight times is correspondingly more effective; for below a certain relative size the value of an advertisement decreases much more rapidly than the cost. There are, of course, modifying conditions, such as special sales of department stores, where occasional displays and announcements make it desirable to use either full pages, or even double pages, but the great bulk of advertising is not of this character.
[Sidenote: Ratio of Size to Value]
Every year in the United States alone six hundred millions of dollars are expended in advertising the sale of commodities, and for the most part expended in a haphazard, experimental and unscientific way. The investment of this vast sum with risk of perhaps total loss, or even possible injury, through the faulty construction or improper placing of advertisements should stimulate the interest of every advertiser in the work that psychologists have done and are doing toward the accumulation of a body of exact knowledge on this subject.
[Sidenote: Risks in Advertising]

THE SCIENCE OF FORGETTING
[Illustration: TESTING THE MEMORY WITH PROFESSOR JASTROW'S MEMORY APPARATUS PRIVATE LABORATORY, SOCIETY OF APPLIED PSYCHOLOGY]
[Illustration: Decorative Header]

CHAPTER V
THE SCIENCE OF FORGETTING
[Sidenote: The Skilled Artisan]
Attention is the instrumentality through which the Laws of Recall operate. Wittingly or unwittingly, consciously or unconsciously, every man's attention swings in automatic obedience to the Laws of Recall.
Attention is the artisan that, bit by bit, and with lightning quickness, constructs the mosaic of consciousness.
Having the whole vast store of all present and past experiences to draw upon, he selects only those groups and those isolated instances that are related to our general interests and aims. He disregards others.
[Sidenote: How the Attention Works]
The attention operates in a manner complementary to the general Laws of Recall. It is an active principle not of association, but of dissociation.
You choose, for example, a certain aim in life. You decide to become the inventor of an aeroplane of automatic stability. This choice henceforth determines two things. First, it determines just which of the sensory experiences of any given moment are most likely to be selected for your conscious perception. Secondly, it determines just which of your past experiences will be most likely to be recalled.
Such a choice, in other words, determines to some extent the sort of elements that will most probably be selected to make up at any moment the contents of your consciousness.
[Sidenote: