S T R EAM O F T H OU GH T I N SA LE 2 1
a. Th e p rac tic e s which h ave p ersist ed ove r
a p e rio d of yea rs h ave p rob ably b ee n of val ue.
We infe r ei th e r t h a t. tho se fi rm s which did
no t foll ow the s e pra c tice s did no t m ake e nough
m oney t o e nabl e th em to c on tinu e to a dver
tise ; o r th a t th o se which did c ontinue to
a dve rti se, disc overed th e differenc e b e tw een
valuel es s an d valuabl e p rac tic es an d a dopt e d
th e l a tte r.
We mus t n o t assum e th a t sell ers ma de th es e
ch an ge s a s a resul t o f co n scio u s disc overi e s.
Th ey w orke d mainly by tri al an d e rro r. As
indicat e d i n Fi gu re^4 , th ey disc overe d th e
useful ne ss o f l owe r-case typ e in h ea dline s onl y
a fte r a l on g-exten de d p e rio d of experi men ta
ti on.
We m ay regard m ode rn sellin g p ractic e s,
th en, a s produc ts o f unc on scio u s evol u tion.
In t h e struggl e fo r exi stenc e i n th e w orl d o f
publici ty, c er tai n fea t ure s h ave su rvive d be
c ause o f c erta i n p sych ol ogical el ement s of
st rengt h a nd fi tn es s. Th ey exemplify a so rt
o f economic “ survival of th e fi ttest. ”
b. A secon d a ssump tion we m ake i n
u tilizing th e “ hi sto rical ” m e th o d i s th at if
sell er's h a d st udie d th e p racti ce s of th ei r pre
dec essor-s th ey migh t h ave avoide d som e e rro rs
and migh t h ave elimina ted m uc h w a sta ge.