The object is illumined, heated, set on fire. Impressions are so deep that they

can never be effaced. Attention of this sort is the prime condition of the most

productive mental labor.

 

--DANIEL PUTNAM, _Psychology_.

 

Try to rub the top of your head forward and backward at the same time that you

are patting your chest. Unless your powers of cooerdination are well developed

you will find it confusing, if not impossible. The brain needs special training

before it can do two or more things efficiently at the same instant. It may seem

like splitting a hair between its north and northwest corner, but some

psychologists argue that _no_ brain can think two distinct thoughts, absolutely

simultaneously--that what seems to be simultaneous is really very rapid rotation

from the first thought to the second and back again, just as in the above-cited

experiment the attention must shift from one hand to the other until one or the

other movement becomes partly or wholly automatic.

 

Whatever is the psychological truth of this contention it is undeniable that the

mind measurably loses grip on one idea the moment the attention is projected

decidedly ahead to a second or a third idea.

 

A fault in public speakers that is as pernicious as it is common is that they

try to think of the succeeding sentence while still uttering the former, and in

this way their concentration trails off; in consequence, they start their

sentences strongly and end them weakly. In a well-prepared written speech the