38 TH E M I N D OF THE BUY E R
in a p erfec tly unch ange d c ondi tion, psych o l o
gi sts h ave di scovere d some evi denc e tha t th e
p eri od m ay b e two or th re e minute s, bu t fa r
more c ommonl y, only a sec on d o r two in
l en gth. Aft er thi s len gth o f tim e i n th e vo rtex
of th e stream an obj ec t mu st gi ve way to a n
oth e r o ne which h a s be en h overi ng o n th eF IG. (^5).
m argin waiting fo r a ch anc e to wedge it self
in. B e i t remembe re d th a t a t any on e mo~
men t th e re a re m any things variously di s
trib ute d i n th e m ent al st ream. A c ross- sec
tion w oul d reveal a c ondition resemblin g th a t
pic t ured i n Figure (^5) , wh e re obj ec t A ( l e t i t
b e a s tre et-ca r a dve rtisem ent of B unte Cough
D rops ) give s w ay af ter a b ri ef dominanc e
ove r th e c ente r of a ttention , to obj ec t B ( a n
adj oining a dvertisemen t o f Arrow c ollars ) ;