it is in the cache.
Trang 1RAYMONDE G U I N D O N
M i c r o e l e o t r o n l c s a n d C o m p u t e r T e c h n o l o g y C o r p o r a t i o n
(MCC)
9 4 3 0 R e s e a r c h Blvd
Austin, T e x a s ?8759
A n a p h o r a r e s o l u t i o n is t h e p r o c e s s of
d e t e r m i n i n g t h e r e f e r e n t of ~ u a p h o r s
s u c h as d e f i n i t e n o u n p h r a s e s a n d
p r o n o u n s , in a d i s c o u r s e C o m p u t a t i o n a l
l i n g u i s t s , in m o d e l i n g the p r o c e s s of
a n a p h o r a r e s o l u t i o n , h a v e p r o p o s e d the
n o t i o n of f o c u s i n g F o c u s i n g is t h e
p r o c e s s , e n g a g e d in b y a reader, of
s e l e c t i n g a s u b s e t of the d i s c o u r s e
i t e m s a n d maJ£ing t h e m h i g h l y a v a i l a b l e
for f u r t h e r c o m p u t a t i o n s T h i s p a p e r
p r o v i d e s a c o g n i t i v e b a s i s for a n a p h o r a
r e s o l u t i o n a n d f o c u s i n g H u m a n m e m o r y
is d i v i d e d i n t o a s h o r t - t e r m , an
o p e r a t i n g , a n d a l o n g - t e r m memory
S h o r t - t e r m m e m o r y c a n o n l y c o n t a i n a
s m a l l n u m b e r of m e a n i n g u n i t s a n d its
r e t r i e v a l t i m e is fast S h o r t - t e r m
m e m o r y is d i v i d e d into a c a c h e a n d a
buffer T h e c a c h e c o n t a i n s a s u b s e t of
m e a n i n g u n i t s e x p r e s s e d in the p r e v i o u s
s e n t e n c e s a n d the b u f f e r h o l d s a
r e p r e s e n t a t i o n of ~he i n c o m i n g s e n t e n c e
F o c u s i n g is r e a l i z e d in ~he c a c h e t h a t
c o n t a i n s a s u b s e t of the most t o p i c a l
u n i t s a n d a s u b s e t of the m o s ~ r e c e n t
u n i t s in the text T h e i n f o r m a t i o n
s t o r e d in the c a c h e is u s e d to i n t e g r a t e
~ h e i n c o m i n g s e n t e n c e w i t h the p r e c e d i n g
d i s c o u r s e P r o n o u n s s h o u l d be u s e d to
r e f e r to u n i t s in focus O p e r a t i n g
m e m o r y c o n t a i n s a v e r y l a r g e n u m b e r of
u n i t s but its r e ~ r l e v a l t i m e is slow
It c o n t a i n s t h e p r e v i o u s t e x ~ u n i t s that
a r e not in t h e cache It c o m p r i s e s t h e
tex~ u n i t s n o t in focus D e f i n i t e n o u n
p h r a s e s s h o u l d b e u s e d to r e f e r t o u n i t e
not in focus T w o e m p i r i c a l s t u d i e s a r e
d e s c r i b e d that d e m o n s t r a t e t h e c o g n i t i v e
b a s i s for f o c u s i n g , the u s e of d e f i n i t e
n o u n p h r a s e s to r e f e r to a n t e c e d e n t s not
in focus, a n d the u s e of p r o n o u n s to
r e f e r to a n t e c e d e n t s in focus
T h e goal of t h l s r e s e a r c h is to
s h o w the r e l a t i o n b e t w e e n the
p s y c h o l o g i c a l w o r k on a n a p h o r a
r e s o l u t i o n b a s e d on t h e n o t i o n of a
l i m i t e d s h o r t - t e r m or w o r k i n g m e m o r y a n d
t h e c o m p u t a t i o n a l l i n g u i s t i c s w o r k b a s e d
on t h e n o t i o n of f o c u s i n g
T h i s r a p p r o c h e m e n t is i m p o r t a n t for
t h e f o l l o w i n g reasons:
I) F r o m a t h e o r e t i c a l v i e w p o i n t
c o g n i t i v e e v i d e n c e i n c r e a s e s the
v a l i d i t y of t h e c o m p u t a t i o n a l n o t i o n of focus
2) F o c u s i n g c o r r e s p o n d s to one of t h e
r e a d e r ' s c o m p r e h e n s i o n p r o c e s s e s a n d it
n e e d s to be i n c o r p o r a t e d in the m o d e l of the u s e r in l a n g u a g e u n d e r s t a n d i n g
s y s t e m s to a d e q u a t e l y r e s o l v e
a m ~ i g u i t l e s in the u s e r ' s u t t e r a n c e s a n d
to h a n d l e l a n g u a g e g e n e r a t i o n
F O C U S I N G IN C O M P U T A T I O N A L L I N G U I S T I C S
A c c o r d i n g to G r o s z ( 1 9 7 7 ) who w a s
i n t e r e s t e d in ~he r e s o l u t i o n of d e f i n i t e
n o u n p h r a s e s , f o c u s i n g is the p r o c e s s
e n g a g e d in by p a r t i c i p a n t s in a
d i s c o u r s e , of h i g h l i g h t i n g a s u b s e t of
t h e i r s h a r e d reality G r o s z Joshi a n d
w e i n s t e i n (1983) d i s t i n g u i s h b e t w e e n two
l e v e l s of focus, g l o b a l f o c u s a n d
c e n t e r i m g G l o b a l f o c u s i n g is a m a j o r
f a c t o r in m a i n t a i n i n g g l o b a l c o h e r e n c e
a n d i n the i n t e r p r e t a t i o n of d e f i n i t e
n o u n p h r a s e s C e n t e r i n g is a m a j o r
f a c t o r in m a i n t a i n i n g l o c a l c o h e r e n c e
a n d in t h e i n t e r p r e t a t i o n of p r o n o u n s
Grosz Joshi a n d W e i n s t e i n f u r t h e r
d e f i n e the n o t i o n of c e n t e r i n g E a c h
s e n t e n c e h a s two t y p e s of c e n t e r s w h o s e
p u r p o s e is t o i n t e g r a t e the s e n t e n c e t o the d i s c o u r s e T h e b a c k w a r d - l o o k i n g
c e n t e r l i n k s t h e c u r r e n t s e n t e n c e to t h e
p r e c e d i n g d i s c o u r s e T h e set of
f o r w a r d - l o o k l n g c e n t e r s p r o v i d e s t h ~ set
of e n t i t i e s to w h i c h f u r t h e r a n a p h o r s
m ~ y refer T h e b 6 o k w ~ r d - l o o k l n g c e n t e r
c o r r e s p o n d s , roughly.- to S i d n e r ' s f o c u s
a n d t h e f o r w a r d - l o o k l n g c e n t e r s to
S i d n e r ' s potentla~l fool
~ 8
Trang 2O n e p r i n c i p l e d e r i v e d b y Grosz,
Joshl, a n d W e i n s ~ e i n is t h e f o l l o w i n g :
if t h e b ~ o k w a r d - l o o k i n g c e n t e r of t h e
o u r r e n ~ u t t e r a n c e is the s a m e as the
b a o k w a r d - l o o k l n g c e n ~ e r of the p r e v i o u s
u t t e r a n c e , a p r o n o u n s h o u l d be used In
o t h e r words, if t h e r e a r e no ~ o p l c
shifts, c o n t i n u e to r e f e r to the s a m e
e n t i t y b y u s i n g a pronoun
H o w e v e r , v i o l a t i o n s of- t h i s
p r i n c i p l e h a v e b e e n p r e s e n t e d in G r o s z
(1977) a n d n o t e d in Grosz, Joshl, a n d
W e l n s ~ e l n (198~) They h a v e s h o w n that
p r o n o u n s a r e s o m e t i m e s u s e d to r e f e r to
e n t i t i e s m e n t i o n e d m a n y s e n t e n c e s back,
e v e n t h o u g h the b a c k w a r d - l o o k l n g c e n t e r
of i n t e r v e n i n g s e n t e n c e s h a s b e e n
c h a n g e d b y t o p i c shifts
S i d n e r (19V9 1983) h a s p r o p o s e d
t h e n o t i o n of focus in the c o n t e x t of
i n t e r p r e t i n g anaphors, e s p e c i a l l y
pronouns In S i d n e r ' s theory, a n
a n a p h o r n e i t h e r r e f e r s ~o a n o t h e r w o r d
nor c o - r e f e r s to a n o t h e r word but
r a t h e r c o - s p e c i f i e s a c o g n i t i v e e l e m e n ~
in the r e a d e r ' s mind Moreover a
t h e o r y of a n & p h o r a r e s o l u t i o n must
p r e d i c t the p a t t e r n of r e a d e r ' s c o r r e c t
a n d i n c o r r e c t c h o i c e s of c o - s p e c i f i e r s
a n d ~he f a i l u r e s ~o u n d e r s t a n d T h i s
v i e w m a k e s e x p l i c i t the c o n s i d e r a t i o n of
the r e a d e r ' s m e n t a l m o d e l a n d
i n f e r e n t i a l c a p a ~ b i l i ~ i e s
A s E e t c h of S i d n e r ' s f o c u s i n g
p r o c e s s follows First a n i n i t i a l
focus is s e l e c t e d on the b a s i s of
s y n t a c t i c f e a t u r e s a n d t h e m a t i c r o l e s
i n d i c a t i n g t o p l c ~ l i t y in the flrs~
sentence O t h e r e l e m e n t s i n t r o d u c e d in
the s e n t e n c e a r e s t o r e d as p o t e n t i a l
loci for l a t e r s e n t e n c e s W h e n an
a n a p h o r l c e x p r e s s i o n is e n c o u n t e r e d
this f o c u s is t e s t e d as a c o - s p e c l f l e r
for ~he anaphor It h a s to s a t i s f y
s y n t a o t l o r e s ~ r l o ~ i o n s on c o - r e f e r e n c e s
(L~snlk, 1976), s e m a n t i c s e l e o ~ i o n a l
r e s t r l o ~ i o n s (Katz a n d Fodor, 1963), a n d
p r a g m a t i c p l a u s i b i l i t y o o n s ~ r a l n ~ s
e x p r e s s e d i n the r e m a i n d e r of the
sentence If the f o c u s f a i l s ~s a
c o - s p e c l f i e r for t h e ~ n ~ p h o r , the
p o t e n t i a l fool a r e t r i e d in turn At
the s a m e time, t h e n e w e l e m e n t s
i n t r o d u c e d in the s e n t e n c e are s t o r e d as
p o t e n t i a l loci for l a t e r sentences
Third, the f o c u s is u p d a t e d to the
s e l e c t e d c o - s p e c l f l e r for the anaphor
If the f o c u s has changed, a t o p i c s ~ i f t
has occurred T h e s e c o n d a n d t h i r d
s ~ e p s a r e c y c l i c a l l y a p p l i e d a f t e r e a c h
s e n t e n c e
T h e a d v a n t a g e of u s i n g a focus
m e c h a n i s m is tha~ it p r i o r l t l z e s a n d
r e s t r l c ~ s the s e a r c h for a c o - s p e c l f i e r ,
a n d as a c o n s e q u e n c e , r e d u c e s t h e
o o m p u t a t l o n ~ l c o s t s a s s o o l a t e d w i t h
i n f e r e n t i a l p r o c e s s i n g w h e n t e s t l n ~ the
a p p l i c a b i l i t y of the o o - s p e c l f l e r to the
a n a p h o r
C O G N I T I V E S T U D I E S O F A N A P H O R A R E S O L U T I O N
A few r e p r e s e n t a t i v e e m p i r i c a l
s t u d i e s of a n a p h o r a r e s o l u t i o n are
d e s c r i b e d below A l l the e x p e r i m e n t a l
p a r ~ d l g m s u s e d s h a r e the f o l l o w i n g
a s s u m p t i o n s : 1) h u m a n m e m o r y is f u n c ~ i o n a l l y or
s ~ r u c ~ u r a l l y d i v i d e d i n t o at l e a s t two
t y p e s of m e m o r i e s , a s h o r t - t e r m m e m o r y
w i t h s m a l l s t o r a g e c a p a c i t y but v e r y fast r e t r i e v a l t i m e a n d a l o n g - t e r m
m e m o r y w i t h v e r y l a r g e s ~ o r a g e c a p a c i t y but s l o w r e t r i e v a l time:
2) a t o p i c s h i f t t r a n s f e r s the u n i t s
c u r r e n t l y in s h o r t - t e r m m e m o r y to
l o n ~ - t e r m memory:
3) ~ n a n a p h o r t r a n s f e r s its r e f e r e n t
f r o m l o n g - t e r m m e m o r y to s h o r t - t e r m
m e m o r y (i.e r e i n s t a t e s its r e f e r e n t ) ,
if it was not a l r e a d y in s h o r t - t e r m memory
T h e first a s s u m p t i o n is crucial
O t h e r t h i n g s b e i n g equal, c o m p u t a t i o n s
i n v o l v i n g r e t r i e v a l f r o m s h o r t - t e r m
m e m o r y w i l l be f a s t e r t h a n t h o s e
i n v o l v i n g r e t r i e v a l f r o m l o n g - t e r m memory T u r n i n g to the s e c o n d
a s s u m p t i o n , t o p i c s h i f t s h a v e b e e n f o u n d
to be i n d u c e d w l t h a v a r i f y of
l i n g u l s % i c devices O n e of the d e v i c e s
is the i n t r o d u c t i o n of i n t e r v e n i n g
s e n t e n c e s b e t w e e n the r e f e r e n t a n d its
a n a p h o r The i n t e r v e n i n g s e n t e n c e s are
u n r e l a t e d zo the r e f e r e n t but r e l a t e d to the o v e r a l l text A n o t h e r d e v i c e is the
s p e c i f i c a t i o n of a t e m p o r a l or S p a t i a l
p a r a m e t e r that is o u t s i d e the n o r m a l
r a n g e of a s i t u a t i o n W h e n d e s c r i b i n g a
d i n n e r , the p h r a s e "Five h o u r s l a t e r , "
s i g n a l s ~h~t the t o p i c of c o n v e r s a t i o n
is no l o n g e r t h e d i n n e r A n o t h e r d e v i c e
is the use of an a n a p h o r , f r e q u e n t l y a
d e f l n l t e n o u n phrase, to r e f e r to a n
a n t e c e d e n t tha~ is not c u r r e n t l y the
t o p i c of c o n v e r s a t i o n b u ~ is in the
" b a c k g r o u n d " Finally, t h e r e is the u s e
of k e y p h r a s e s to s i g n a l a d i v e r s i o n in the f l o w of d i s c o u r s e , s u c h as "Let's
t u r n to." as d o c u m e n t e d in R e l c h m a n (1978, 1984)
The g e n e r a l p a t t e r n for the
m a t e r i a l u s e d in t h e s e e x p e r i m e n t s is the following A~ the b e g i n n i n g of the tex~ a p p e a r s a s e n t e n c e c o n t a i n i n g a
r e f e r e n t (e.g b i o l o g i s t ) For example, "The m i s s i o n i n c l u d e d a
b i o l o g i s t " Then, if ~ h e r e f e r e n t
s h o u l d not be in focus, the n e x ~
s e n t e n c e or s e n t e n c e s i n d l o a t e a t o p i c
s h i f t as d e s c r i b e d aJ3ovs (e.g
Trang 3t h e r e f e r e n t s h o u l d be in focus, no
d e v i c e s for t o p i c s h i f t s are used The
f o l l o w i n g s e n t e n c e t h e n c o n t a i n s an
a n & p h o r (e.g s c i e n t i s t , he) to the
f o c u s e d or n o n - f o c u s e d r e f e r e n t (e.g
b i o l o g i s t ) For example, "The s c i e n t l s t
c o l l e c t e d s a m p l e s from the cultures"
A n o t h e r e x a m p l e is s h o w n in T a b l e 1 of
t h i s paper
C a r p e n t e r a n d Just (1977) u s e d eye
t r a o k l n g w i t h other c o n v e r g i n g
t e c h n i q u e s to s t u d y a n a p h o r a r e s o l u t i o n
W l t h e y e t r a c k i n g , one can m o n i t o r v e r y
p r e c i s e l y the t r a j e c t o r y of the eyes,
w i t h t h e i r f o r w a r d and r e g r e s s i v e
m o v e m e n t s , a n d the d u r a t i o n of eye
f i x a t i o n s on s m a l l s e g m e n t s of the t e ~
T h e a s s u m p t i o n b e h i n d u s i n g this
t e c h n i q u e is that eye m o v e m e n t s are
c l o s e l y r e l a t e d to h i g h e r l e v e l
c o g n i t i v e a c t i v i t i e s s u c h as
c o m p r e h e n s i o n T h e r e f o r e one c a n
e x p e c t l o n g e r f i x a t i o n d u r a t i o n s on text
s e g m e n t s r e q u i r i n g a d d i t i o n a l p r o c e s s i n g
to be c o m p r e h e n d e d and one c a n expect
the eye m o v e m e n t p a t t e r n to m i r r o r the
s e l e c t i v e p i c k u p of i m p o r t a n t
i n f o r m a t i o n in the text
T h e y p e r f o r m e d a s e r i e s of
e x p e r i m e n t s t e s t l n ~ the e f f e c t of
r e c e n c y of a r e f e r e n t on the t i m e c o u r s e
of a n a p h o r a resolution Indirectly
t h e y t e s t e d the e f f e c t of r e c e n c y on the
a v a i l a b i l i t y of an item in s h o r t - t e r m
memory T h e y p r e s e n t e d t e x t s w h e r e the
n u m b e r of s e n t e n c e s b e t w e e n the r e f e r e n t
a n d the a n a p h o r was v a r i e d from zero to
three The s u b j e c t s read e a c h s e n t e n c e
and a f t e r the sentence, h a d to d e c i d e
w h e t h e r it was c o n s i s t e n t or
i n c o n s i s t e n t w i t h the p r e v i o u s
s e n t e n c e s T h e c o n s i s t e n c y J u d g m e n t
t i m e s a n d the eye f i x a t i o n s were
recorded T h e c o n s i s t e n c y J u d g m e n t
task, u s e d as c o n v e r g i n g e v i d e n c e w i t h
the eye m o v e m e n t technique, is b e l i e v e d
to i n d u c e the s u b j e c t s to i n t e g r a t e e a c h
n e w s e n t e n c e a n d s h o u l d pars,llel the
d i f f i c u l t y of ~ p h o r a r e s o l u t i o n T h e
o v e r a l l r e a d i n g t i m e of the ~ n & p h o r l o
s e n t e n c e w a s m e a s u r e d u s i n g the eye
t r a c k i n g t e c h n i q u e E a c h of t h e s e t a s k s
s h o u l d be f a s t e r if the r e f e r e n t was in
s h o r t - t e r m m e m o r y t h a n if the referent
w a s i n l o n g - t e r m memory
R e s p o n s e t i m e s for the c o n s i s t e n c y
J u d g m e n t s a n d r e a d i n g t i m e s of the
a n a p h o r l c s e n t e n c e s i n c r e a s e d as the
n - m h e r of i n t e r v e n i n g s e n t e n c e s
i n c r e a s e d The s h a r p e s t d i f f e r e n c e
a p p e a r e d b e t w e e n zero and one
i n t e r v e n i n g sentence G a z e d u r a t i o n s
w i t h i n the a n a p h o r l o s e n t e n c e w e r e
s h o r t e r w h e n t h e r e w e r e no i n t e r v e n l n g
s e n t e n c e s t h ~ n in the other conditions
T h e s e r e s u l t s s h o w not o n l y that
& n a p h o r a r e s o l u t i o n is e a s i e r w h e n the
r e f e r e n t is n e a r e r the ~ n a p h o r but a l s o that one i n t e r v e n l n E s e n t e n c e m a y be
s u f f l o l e n t to p r o d u c e a t o p i c shift
C l a r e a n d S e n g u l (1979) u s e d the
s e n t e n c e r e a d i n g t i m e t e c h n i q u e to s t u d y
a n a p h o r a r e s o l u t i o n In t h i s t e c h n i q u e
s u b j e c t s c o n t r o l the onset a n d o f f s e t of the p r e s e n t a t i o n of a s e n t e n c e by
p r e s s i n g a button The s u b j e c t s are
i n s t r u c t e d to p r e s s the b u t t o n to see a
n e w s e n t e n c e as s o o n as t h e y h a v e
u n d e r s t o o d the c u r r e n t sentence The
a s s u m p t i o n b e h i n d this t e c h n i q u e is that
a d d i t i o n a l p r o c e s s i n g r e q u i r e d for
c o m p r e h e n s i o n w i l l i n c r e a s e s e n t e n c e
r e a d i n g time
C l a r e a n d S e n g u l (1979) m e a s u r e d the r e a d i n g t i m e of a s e n t e n c e
c o n t a i n i n g a n anaphor T h e y
d i s t i n g u i s h e d b e t w e e n two m o d e l s of the
e f f e c t of r e c e n c y of a r e f e r e n t on the
s p e e d of ~ n a p h o r a r e s o l u t i o n In the first model, c a l l e d the " c o n t i n u i t y model", e n t i t i e s m e n t i o n e d in the
d i s c o u r s e are s e a r c h e d b a c k w a r d from the last one O n e s h o u l d e x p e c t
m o n o t o n i c a l l y i n c r e a s i n g r e ~ d i n ~ time as the s e a r c h e d e n t i t y is f a r t h e r back In the s e c o n d model, c a l l e d the
" d i s c o n t i n u i t y model", e n t i t i e s
m e n t i o n e d in the c u r r e n t or last
s e n t e n c e are kept in s h o r t - t e r m m e m o r y
a n d a c c e s s e d first All the e n t i t i e s that are f u r t h e r b a c k are m o r e l i k e l y to
be in l o n g - t e r m m e m o r y (and not in
s h o r ~ - t e r m m e m o r y ) and a c c e s s e d second
S u b j e c t s r e a ~ s h o r t p a r a g r a p h s
w h e r e a r e f e r e n t c o u l d be s e p a r a t e d from the a n a p h o r by zero ~o two i n t e r v e n i n ~
s e n t e n c e s T h e r e a d l n ~ t i m e of ~he
s e n t e n c e c o n t a i n i n g the a n a p h o r was fast
w h e n the r e f e r e n t was in the i m m e d i a t e l y
p r e c e d i n g s e n t e n c e but ~ a l l x ~ w h e n
it was two or t h r e e s e n t e n c e s before
T h i s f i n d i n g s u p p o r t s t h e d i s c o n t i n u i t y model E n t i t i e s in t h e last p r o c e s s i n g
c y c l e are m o r e l i k e l y to be kept in
s h o r t - t e r m m e m o r y t h a n e n t i t i e s in
p r e v i o u s l y p r o c e s s e d cycles O n c e a tex~ e n t i t y is not i n s h o r t - t e r m , the
n u m b e r of i n t e r v e n i n g s e n t e n c e s d o e s not
a f f e c t the s p e e d of a n ~ p h o r a resolution
Lesgold, Roth, a n d C u r t i s (1979),
w h o r e l a t e d t h e l i n g u i s t i c n o t i o n of
f o r e g r o u n d i n g (Chafe, 1972) to ~he
p s y c h o l o g i c a l n o t i o n of s h o r t - t e r m memory, p e r f o r m e d a s e r i e s of
e x p e r i m e n t s s i m i l a r ~o t h o s e of C l a r k
~ n d S e n g u l (1979), u s i n g m o r e v a r i e d
w a y s to p r o d u c e t o p i c shifts, and
r e p l i c a t e d the a b o v e findings
220
Trang 4M c K o o n a n d g a t o l i f f (1980) u s e d a n
a c t i v a t i o n p r o c e d u r e b a s e d on C h a n g
(1980) A d e s o r i p t l o n of the b a s l o
p a r a d i g m a n d its u n d e r l y i n g l o g l o
f o l l o w s W h e n one r e a d s a text, o n l y a
s m a l l p a r t of the text i n f o r m a t i o n is
s t o r e d in s h o r t - t e r m m e m o r y a n d most of
t h e i n f o r m a t i o n is s t o r e d in l o n g - t e r m
m e m o r y T h i s is d u e to t h e v e r y s m a l l
s t o r a g e c a p a c i t y of s h o r t - t e r m m e m o r y (7
t2 c h u n E s ; Miller, 1956) G i v e n t h a t
r e t r i e v a l t i m e in s h o r t - t e r m m e m o r y is
m u c h f a s t e r t h a n r e t r i e v a l t i m e in
l o n g - t e r m memory, it w i l l t a m e l o n g e r to
r e m e m b e r s o m e t h i n g f r o m t h e text if the
m e m o r y is s t o r e d in l o n g - t e r m m e m o r y
t h a n in s h o r t - t e r m memory
In t h e i r study, s u b j e c t s r e a d a
p a r a g r a p h s e n t e n c e b y sentence
I m m e d i a t e l y a f t e r t h e last sentence, the
s u b j e c t s w e r e p r e s e n t e d w i t h a s i n g l e
w o r d a n d the s u b j e c t s h a d to r e m e m b e r
w h e t h e r t h e w o r d h a d a p p e a r e d p r e v i o u s l y
in t h e text or not (an o l d - n e w
r e c o g n i t i o n ) If the t e s t e d w o r d was
s t i l l in s h o r t - t e r m memory, the o l d - n e w
r e c o g n i t i o n t i m e s h o u l d be f a s t e r t h a n
if it w a s in l o n g - t e r m memory
To test t h i s h y p o t h e s i s , the
p a r a g r a p h s w e r e c o n s t r u c t e d in the
f o l l o w i n g manner T h e r e f e r e n t (e.g
b u r g l a r ) was s e p a r a t e d from the a n a p h o r
by e i t h e r z e r o or ~wo i n ~ e r v e n l n g
s e n t e n c e s T h e a n a p h o r a p p e a r e d in the
last s e n t e n c e of the p a r a g r a p h The
last s e n t e n c e was p r e s e n t e d in one of
t h r e e v e r s i o n s : i) the s u b j e c t of the
s e n t e n c e was a r e p e t i t i o n (i.e
b u r g l a r ) of the r e f e r e n t in the first
s e n t e n c e ( a n a p h o r i o - i d e n t i o a l ) ; 2) the
s u b j e c t w a s t h e n a m e of the category-
(e.g c r i m i n a l ) in w h i c h the r e f e r e n t
b e l o n g e d ( a n a p h o r l c - c a t e g o r y ) ; 3) the
s u b j e c t w a s a n o u n (e.g ca~) u n r e l a t e d
~o t h e r e f e r e n t ( n o n - a n a p h o r i c ) D u r i n g
the e x p e r i m e n t a l trials, the "referent"
(i.e b u r g l a r ) w a s p r e s e n t e d
i m m e d i a t e l y a f t e r the last s e n t e n c e for
a n o l d - n e w r e c o g n i t i o n
A s s u m i n g that a n a n a p h o r a c t i v a t e s
its r e f e r e n t b y m a k i n g it a v a i l a b l e in
s h o r t - t e r m memory, one c a n e x p e c t
s l g n i f l o a n t l y f a s t e r o l d - n e w r e c o g n i t i o n
t i m e s for "burglar" in the
a n a p h o r l c - c a ~ e g o r y o o n d i ~ l o n t h a n in the
n o n - a n a p h o r l o c o n d i t i o n This
p r e d i c t i o n w a s observed
S u r p r i s i n g l y , the n u m b e r of
i n t e r v e n i n g s e n t e n c e s d i d not h a v e an
e f f e c t T h i s s u g g e s t s that the two
i n t e r v e n i n g s e n t e n c e s d i d not r e m o v e the
r e f e r e n t from s h o r t - t e r m m e m o r y (i.e
" b a c k g r o u n d s " the referent) It is
p r o b a b l y not the case Rather i~ is
l l k e l y that by t e s t i n g the r e f e r e n t at
w h e n t h e a n a p h o r is e n c o u n t e r e d , the
r e f e r e n t h a d t i m e to b e r e i n s t a t e d in
s h o r ~ - t e r m m e m o r y a n d be h i g h l y
a v a i l a b l e T h i s is a n i m p o r t a n t point
T h e a c t i v a t i o n p r o c e d u r e w a s not o n - l l n e
s i n c e t h e o l d - n e w r e c o g n i t i o n o c o u r e d at
t h e ~ n ~ of the s e n t e n c e as o p p o s e d to
M ~ l l ~ t h e s e n t e n c e was r e a d a n d the
a n a p h o r e n c o u n t e r e d
A n o t h e r i n i t i a l l y s u r p r i s i n g e f f e c t
w a s t h a t ~he o l d - n e w r e c o g n i t i o n t i m e s
for t h e r e f e r e n t s w e r e s l o w e r in the zero i n t e r v e n i n g s e n t e n c e s w h e n the
a n a p h o r w a s a r e p e t i t i o n of the r e f e r e n t
i t s e l f t h a n w h e n the a n a p h o r was the
c a t e g o r y name T h i s last r e s u l t
s u g g e s t s t h a t it is not a p p r o p r i a t e to
u s e a d e f i n i t e n o u n phrase, e s p e c i a l l y a
r e p e t i t i o n of the r e f e r e n t , to r e f e r to
a a n t e c e d e n t in s h o r t - t e r m memory
A s e x p l a i n e d p r e v i o u s l y ,
i n t e r v e n i n g s e n t e n c e s a r e not the o n l y
d e v i c e s that t r a n s f e r text u n i t s f r o m
s h o r t - t e r m to l o n g - t e r m memory
S t e r e o t y p i c a l s i t u a t i o n s h a v e s p a t i a l
a n d t e m p o r a l p a r a m e t e r s w i t h l e g a l
r a n g e s of values If one s p e c i f i e s a
s p a t i a l or ~ e m p o r a l v a l u e o u t s i d e t h e s e ranges, a s c e n a r i o - s h i f t occurs For
e x a m p l e A n d e r s o n (in S a n f o r d a n d
G a r r o d o 1981) c o n s t r u c t e d t e x t s a b o u t
s t e r e o t y p i c a l s i t u a t i o n s s u c h as g o i n g
to a r e s t a u r a n t In one s e n t e n c e of the text, t h e r e w a s a r e f e r e n c e to a
c h a r a c t e r r e l a t e d to the script, say a waiter AZ the b e g i n n i n g of the next
s e n t e n c e , t h e r e w a s a m e n t i o n of a
t e m p o r a l or s p a t i a l p a r a m e t e r , s u c h as
"One h o u r later" or "Five h o u r s la~er"
In the flrs~ c a s e the p a r a m e t e r is
w i t h i n the r a n g e d e f i n i n g the scrip~, in the s e c o n d c a s e it is not The rest of
~ h e s e n t e n c e c o n t a i n e d an a n a p h o r to the
p r e v i o u s l y m e n t i o n e d c h a r a c t e r , the walter M e a s u m l n g ~he r e a d i n g t i m e of
t h e a n a p h o r l o s e n t e n c e A n d e r s o n s h o w e d
l o n g e r r e a d i n g t i m e w h e n t h e s p a t i a l or
t e m p o r a l p a r a m e t e r w ~ s o u t s i d e the r a n g e
of t h e s c r i p t t h ~ n inside T h i s
s u g g e s t s that the r e f e r e n t w a s
t r a n s f e r e d from s h o r t - t e r m to l o n g - t e r m
m e m o r y b y the s c e n a r l o - s h l f t a n d it t o o k
l o n g e r ~o r e t r i e v e the r e f e r e n t d u r i n g
a n a p h o r a r e s o l u t i o n
T h e r e s u l t s from all t h e s e
e x p e r i m e n t s s u p p o r t the n o t i o n tha~ an
a n a p h o r a c t i v a t e s its r e f e r e n t by malting
it h i g h l y a v a i l a b l e in s h o r t - t e r m m e m o r y
a n d ~hat t o p i c s h i f t s t r a n s f e r u n i t s
f r o m s h o r t - t e r m m e m o r y to l o n g - t e r m memoz'y However n o n e of t h e s e studles~
e x c e p t some eye m o v e m e n t siudles
p r o v i d e d a t a on ~ a n a p h o r a r e s o l u t i o n
o c c u r s d u r i n g t h e r e a d i n g of a s e n t e n c e
~ n d w h e n i~ o o o u 2 s in r e l a t i o n to the
Trang 5l e x i o a l , s y n t a c t i c
p r a g m a t i c a n a l y s e s
s e m a n t i c , a n d
C O G N I T I V E B A S I S F O R F O C U S I N G
A s k e t c h of a c o g n i t i v e m o d e l of
a n a p h o r a r e s o l u t i o n is o f f e r e d here It
h a s b e e n h e a v i l y i n f l u e n c e d b y the
short-term~long-term m e m o r y m o d e l of
K i n t s c h a n d v a n D i J k (19~8) a n d
e s p e c i a l l y its l e a d i n g e d g e s t r a t e g y
~ t r u c t u r e ~ f ~ m e m g / ~
A n a l o g i c a l l y , h u m a n m e m o r y c a n be
c o n c e p t u a l i z e d as a t h r e e l e v e l
s t r u c t u r e s i m i l a r to t h e m e m o r y of m o s t
m i n i a n d m a i n frame c o m p u t e r s It
c o n s i s t s of a small, v e r y fast m e m o r y
c a l l e d s h o r t - t e r m m e m o r y (STM); a
r e l a t i v e l y l a r g e r m a i n or o p e r a t i n g
m e m o r y (OM): a n d a v a s t s t o r e of
g e n e r a l w o r l d k n o w l e d g e c a l l e d l o n g - t e r m
m e m o r y (LTM)
T h e t o t a l STM is o n l y l a r g e e n o u g h
to c o n t a i n 7 t 2 c h u n k s of i n f o r m a t i o n at
a n y one t i m e (Simon, 1974; Miller
d y n a m i c a l l y a l l o c a t e d to one of two
uses First, par~ of the STM is u s e d to
s t o r e the i n c o m i n g s e n t e n c e or clause
T h i s is a t e m p o r a r y s t o r a g e of the
s e n t e n c e or c l a u s e b e f o r e f u r t h e r
p r o c e s s i n g a n d is c a l l e d the STM buffer
The s e c o n d part of STM is c a l l e d the STM
cache It is u s e d to h o l d over from
one s e n t e n c e or c l a u s e to the next the
i n f o r m a t i o n n e c e s s a r y to p r o v i d e l o c a l
a n d g l o b a l c o h e r e n c e It c o n t a i n s a
s u b s e t of t h e p r e v i o u s text i t e m s that
are t o p i c a l a n d a s u b s e t of t h o s e that
a r e recent R e t r i e v a l t i m e s f r o m
s h o r t - t e r m m e m o r y are v e r y fast
C o n c e p t u a l l y o p e r a t i n g m e m o r y is
t h e s u b s e t of the w o r l d k n o w l e d g e in
l o n g - t e r m m e m o r y w h i c h is d e e m e d
r e l e v ~ n ~ to the p r o o e s s l n g of t h e
c u r r e n t par~ of the text It a l s o
c o n t a i n s t h e g r o w i n g m e m o r y s t r u c t u r e
o o r r s s p o n d i n ~ to the t e x ~ r e a d so f~r
I~ c o n t a i n s t h e less t o p i c a l a n d l e s s
r e c e n t i n f o r m a t i o n from the text
R e t r i e v a l t i m e s are m u c h l o n g e r t h a n for
s h o r t - t e r m memory
The t i m e c o u r s e of a n a p h o r a
r e s o l u t i o n is g r e a t l y d e t e r m i n e d by the
c u r r e n t c o n t e n t of s h o r ~ - t e r m m e m o r y a n d
of o p e r a t i n g memory Moroever, p r o n o u n s
a n d d e f i n i t e n o u n p h r a s e s are r e s o l v e d
u s i n g d i f f e r e n t s ~ r a t e g i e s
C a c h e ~ D u r i n g the i n p u t
of a s e n t e n c e into t h e b u f f e r ~ n d the
c o n c u r r e n t i n t e g r a t i o n of the s e n t e n c e
i n t o the cache, a s u b s e t of the s e m a n t i c
u n i t s h e l d in the STM is s e l e c t e d to be
h e l d o v e r in the c a c h e for the n e x t cycle F o l l o w i n g E l n t s c h a n d v a n D i j k (1978), t h e c a c h e m a n a g e m e n t s t r a t e g y
s e l e c t s a s u b s e t T of t h e m o s t t o p i c a l
i t e m s a n d a s u b s e t R of the m o s t r e c e n t
i t e m s to be h e l d over in t h e cache T h e
s e l e c t i o n s t r a t e g y a i m s at m ~ x l m i z i n ~
t h e p r o b a b i l i t y that a n a n a p h o r in t h e
n e x ~ s e n t e n c e w i l l r e f e r to a s e m a n t i c
u n i t h e l d in the cache C a c h e
m a n a g e m e n t is a p p l i e d a f t e r e a c h
s e n t e n c e or clause
P r o n o u n s a n d d e f i n i t e n o u n p h r a s e s are
r e s o l v e d u s i n g d i f f e r e n t s t r a t e g i e s , we
w i l l d e s c r i b e four cases:
i T h e a n a p h o r is a d e f i n i t e n o u n
p h r a s e a n d the r e f e r e n t is not
in focus, that is, i~ is in
o p e r a t i n g memory,
2 T h e a n a p h o r is a d e f i n i t e n o u n
p h r a s e a n d the r e f e r e n t is in focus, that is it is in the cache
3 T h e a n a p h o r is a p r o n o u n a n d the r e f e r e n t is in the c a c h e (in fOCUS)
4 T h e a n a p h o r is a p r o n o u n a n d the r e f e r e n t is in o p e r a t i n g
m e m o r y (not in focus)
It is h y p o t h e s i z e d that the
e x p l i c i t n e s s of sm a n a p h o r is a signal
u s e d b y the readier, w h i c h d e n o t e s
w h e t h e r the r e f e r e n t is in t h e c a c h e or
in o p e r a t i n g memory
If t h e ~ n a p h o r is a d e f i n i t e n o u n phrase, o p e r a t i n g m e m o r y is s e a r c h e d
i m m e d i a t e l y If t h e r e f e r e n t is in
o p e r a t i n g m e m o r y it is t h e n r e i n s t a t e d
i n t o the cache A t o p i c s h i f t h a s occured
If the a n a p h o r is a d e f i n i t e n o u n
p h r a s e a n d the r e f e r e n t is in f o c u s (i.e in t h e cache), a n a p h o r a
r e s o l u t i o n w i l l be hindered T h e r e a d e r
s e a r c h e s o p e r a t i n g m e m o r y w h i l e the
r e f e r e n t is in s h o r t - t e r m memory
C o r r e s p o n d i n g l y this v i o l a t e s a r u l e of
c o o p e r a t i v e c o m m u n i c a t i o n : u s e a
d e f i n i t e n o u n p h r a s e to r e f e r to an
~ n t e c e d e n t not in focus The d e f i n i t e
n o u n p h r a s e s i g n a l s a t o p i c shift, w h i l e
in fact the s a m e e n t i t y is b e i n g t a l k e d about
Trang 6If t h e a n a p h o r is a pronoun, the
c a c h e is s e a r c h e d for a p l a u s i b l e
r e f e r e n t If found, m n a p h o r a r e s o l u t i o n
is c o m p l e t e d B e c a u s e c a c h e m a n a g e m e n t
is b a s e d on t o p i o a l l t y and recency,
p r o n o u n s c a n r e f e r to ~ h e m a i n ~ o p i o of
~ h e text e v e n w h e n the m a i n ~ o p i o h a s
no~ b e e n m e n t i o n e d d i r e c t l y for m a m y
s e n t e n c e s U n l e s s t h e r e is a g l o b a l
~ o p i c shift, the m a i n t o p i c in the c a c h e
r e m a i n s u n c h a n g e d t h r o u g h o u t ~he text
If the a n a p h o r is a p r o n o u n but no
r e f e r e n t is f o u n d in the cache, it is
t h e n n e c e s s a r y to s e a r c h o p e r a t i n g
memory If a r e f e r e n ~ is f o u n d in
o p e r a t i n g memory, it is r e i n s t a t e d into
t h e c~che A ~ o p i c shift h a s occured
U s i n g a pronoun ~o r e f e r ~o i n f o r m a t i o n
in o p e r a t i n g m e m o r y is d e ~ r l m e n t a l ~o
a m a p h o r a r e s o l u t i o n The r e a d e r first
s e a r c h e s t h e cache ~ h e n ~he o p e r a t i n g
memory, a n d ~ h e n h a s ~o r e l n s t ~ t e ~he
r e f e r e n t i n t o the cache
C O M P A R I S O N S
A c l e a r r e l a t i o n e x i s t s b e t w e e n ~he
n o t i o n of f o c u s i n g p r o p o s e d in
c o m p u t a t i o n a l l i n g u i s t i c s and the m o d e l
of h u m a n m e m o r y a n d d i s c o u r s e p r o c e s s i n g
p r o p o s e d in c o g n i t i v e p s y c h o l o g y
The Q ~ h ~ is u s e d to s t o r e the
i t e m s in f.~Q~ G i v e n the small n u m b e r
of i t e m s s t o r e d in the cache, a s k e t c h y
a n a p h o r s u c h as ~ ~ is s u f f l c l e n ~
to r e t r i e v e the referent The c a c h e
m a n a g e m e n t s t r a t e g y in h u m a n memory is
a i m e d at m a x i m i z i n g ~he p r o b a b i l i t y that
the c a c h e c o n t a i n s the i n f o r m a t i o n
r e l e v a n t to the next c y c l e of
c o m p u t a t i o n T h e cache, by c o n t a i n i n g
t o p i c a l a n d r e c e n ~ i~ems, a l l o w s to
m a i n t a i n g l o b a l a n d l o c a l coherence
Q ~ m ~ y ~ is u s e d ~o s t o r e
i t e m s that a r e not in f ~ A ~ B e c a u s e
the set of i t e m s is large, an
i n f o r m a t i v e d e s c r l p ~ i o n of t h e I t e m ~o
be s e a r c h e d for is needed D ~ f i ~ i ~
~ o u ~ ~ h / ~ e s a / e u s e d ~o i n d l c ~ t e to the
r e a d e r ~ha~ the i ~ e m is no~ in focus
t h u s In o p e r a t i n g memory O t h e r t h i n g s
b e i n g equal, it w i l l tame m o r e time to
r e t r i e v e an i t e m from o p e r a t i n g m e m o r y
t h a n f r o m the cache The r e f e r e n t will
n e e d to be r e i n s t a t e d into the cache
T h i s w i l l p r o d u c e a t o p i c shift The
r e i n s t a t e d r e f e r e n t is t h e n h i g h l y
a v a i l a b l e a n d can be r e f e r r e d to by
u s i n g a pronoun
R E S O L U T I O N
T h e p r e s e n t e d s t u d i e s test the
n o t i o n tha~ f o c u s is c o g n l t i v e l y
r e a l i z e d in t h e r e a d e r ' s l i m i t e d
s h o r t - t e r m memory T h e y a l s o test
G r o s z Joshl a n d W e l n s t e l n ' s c l a i m that
d e f i n i t e n o u n p h r a s e s , a n d not p r o n o u n s ,
s h o u l d be u s e d to r e f e r ~o i t e m s no
l o n g e r in f o c u s a n d ~hat p r o n o u n s , ~nd not d e f i n i t e n o u n phrases, s h o u l d be
u s e d to r e f e r to i t e m s in focus
M o r e o v e r , if one a s s u m e s that the
c o n t e n t of s h o r t - t e r m m e m o r y is
d y n a m i c a l l y u p d a t e d on ~he b a s i s of
r e c e n c y ~ n d t o p i c a l i t y , one can e x p l a i n
w h y p r o n o u n s c a n be u s e d to r e f e r Zo
r e c e n t i t e m s ~ n d a l s o to t o p i c a l
n o n - r e c e n ~ items
A n e w t e c h n i q u e , c a l l e d Q ~ z l i ~
~ i Q n , w a s d e v e l o p e d s p e c i f i c a l l y
to p r o v i d e the e m p i r i c a l d a ~ a for t h e s e
s t u d i e s T h e o n - l i n e a c t i v a t i o n
t e c h n i q u e can be c o m p a r e d to "closely"
t r a c i n g the e x e c u t i o n of ~ program
In the o n - l i n e a c t i v a t i o n
t e c h n i q u e , p a s s a g e s are p r e s e n t e d u s i n g
r a p i d s e r i a l v i s u a l p r e s e n t a t i o n (RSVP),
o n e w o r d a~ a time In ~ d d i t l o n to
r e a d i n g e a c h text the p a r t i c i p a n t s w e r e
a l s o g i v e n t h e ~ a s k to r e c o g n i z e w h e t h e r
s o m e s p e c i a l l y m a r k e d words, p r e s e n t e d
s u r r e p t i t i o u s l y w i ~ h l n ~he ~ext, h a d
a p p e m r e d b e f o r e in the tex~ or not
S o m e of ~ h e s e s p e c i a l w o r d s w e r e
p r e s e n t e d b e f o r e in the text a n d o t h e r s
w e r e not We w i l l call ~hese s p e c i a l l y
m a r k e d w o r d s zest words This t a s k is
c a l l e d a m o l d - n e w r e c o g n i t i o n task
T h e p a s s a g e s c o n t a i n e d a n a p h o r s
r e f e r r i n g ~o a n t e c e d e n t s w h i c h were
e i t h e r in f o c u s or not in focus An
a n t e c e d e n t was r e m o v e d from f o c u s b y
i n t r o d u c i n g a t o p i c shift, w i t h ~he
r e s t r l c ~ i o n that the a n t e c e d e n t was not the m a i n t o p i c of the d i s c o u r s e An
e x a m p l e ter~ is p r e s e n t e d in t a b l e I
N o t e that o n l y one of the a l t e r n a t i v e
s e n t e n c e s 5a, 5b or 50 was p r e s e n t e d for e a c h text to the p a r t i c i p a n t s of the study
In e a c h text one of the test w o r d s was the r e f e r e n t of the anaphor At
s o m e p o i n t b e f o r e or a f t e r the a n a p h o r was p r e s e n t e d on the CRT, its r e f e r e n t was p r e s e n t e d for o l d - n e w r e c o g n i t i o n
a n d r e c o g n i t i o n t i m e s a n d e r r o r s were
c o l l e c t e d The d e l a y b e t w e e n the onse~
of the a n a p h o r a n d the onset of the test
w o r d is c a l l e d the s t i m u l u s onset
a s y n c h r o n y (SOA) The ~ n a p h o r is a c t i n g
as a prime, w h i c h s h o u l d a c t i v a t e the referent The o l d - n e w r e c o g n i t i o n t i m e
for the r e f e r e n t test w o r d i n d i c a t e s
Trang 7in o p e r a t i n g m e m o r y
T A B L E 1
E X A M P L E O F T E X T S W I T H A N T E C E D E N T S
IN F O C U S A N D N O T IN F O C U S
A n t e c e d e n t : t h e r m o m e t e r
A n a p h o r : i n s t r u m e n t
A n t e c e d e n t in F o c u s
1- T h e a s s i s t a n t w a s p r e p a r i n g
s o l u t i o n s for a c h e m i s t r y e x p e r i m e n t
2- T h e e x p e r i m e n t w o u l d t a k e at l e a s t
f o u r hours
3- T h e r e w o u l d t h e n be a t e n h o u r w a i t
for t h e r e a c t i o n to c o m p l e t e
4- He m e a s u r e d t h e t e m p e r a t u r e of a
s o l u t i o n u s i n g a t h e r m o m e t e r
5a- T h e t h i n i n s t r u m e n t w a s not g i v i n g
t h e e x p e c t e d r e ~ d i n g
5b- A b r o k e n i n s t r u m e n t w a s not g i v i n g
the e x p e c t e d reading
5c- T h e c o m p u z e r t e r m i n a l w a s not g i v i n g
the e x p e c t e d reading
A n t e c e d e n t not in F o c u s
I- T h e a s s i s t a n t w a s p r e p a r i n g
s o l u t i o n s for a c h e m i s t r y e x p e r i m e n t
2- He m e a s u r e d the t e m p e r a t u r e of a
s o l u t i o n u s i n g a t h e r m o m e t e r
3- T h e e x p e r i m e n t w o u l d t a k e at l e a s t
four hours
4- T h e r e w o u l d t h e n be a t e n h o u r w ~ i t
for the r e a c t i o n to c o m p l e t e
5a- T h e t h i n i n s t r u m e n t w a s not g i v l n g
the e x p e c t e d reading
5b- A b r o k e n i n s t r u m e n t w a s not g i v i n g
the e x p e c t e d reading
50- T h e c o m p u t e r t e r m i n a l w a s not g i v i n g
t h e e x p e c t e d reading
In a d d i t i o n , t h e r e w e r e t h r e e t y p e s
of primes, as s h o w n in s e n t e n c e s 5a, 5b,
8 ~ d 5o in T a b l e i T h e p r i m e c o u l d be
e i t h e r s e m a n t i c a l l y r e l a t e d a n d
r e f e r e n t i a l (S+R÷) ~ in 5 a ,
s e m a n t i c a l l y r e l a t e d a n d not r e f e r e n t i a l
( S + R - ) as in 5b, o r s e m a n t i c a l l y
u n r e l a t e d a n d not r e f e r e n t i a l (S-R-) as
in 5c In the S÷R÷ c o n d i t i o n , the p r i m e
is t h e a n ~ p h o r T h e t w o c o n d i t i o n s S÷R-
a n d S-R- w e r e c o n t r o l c o n d i t i o n s to
s e p a r a t e the e f f e c t of s e m a n t i c priming,
d u e ~o s e m a n t i c ~ s s o c i a t i o n b e t w e e n the
a n a p h o r a n d the referent, on the o l d - n e w
r e c c g n l t l o n for r e f e r e n t s
A s c h e m a of the p r o c e d u r e is s h o w n
in T a b l e 2 T h e w o r d s s u r r o u n d e d by
s t a r s a ~ e the test words
T A B L E 2
S C H E M A O F T H E P R O C E D U R E
S O A s B e f o r e ~50 m s e c 1250 m s e c
T i m e
T 2 t h i n t h i n t h i n
T ~ " t h e r m o m e t e r * i n s t r u m e n t i n s t r u m e n t
T 4 i n s t r u m e n t * t h e r m o m e t e r " w a s
T 7 g i v i n g g i v i n g * t h e r m o m e t e r "
T h e p r e d i c t i o n s were:
I If a r e f e r e n t is not i n focus,
d u e to a t o p i c shift, the
o o o u r e n o e of t h e a n a p h o r s h o u l d
r e i n s t a t e t h e r e f e r e n t into t h e cache, l e a d i n g to f a s t e r
o l d - n e w r e c o g n i t i o n times In
t e r m s of the e x p e r i m e n t a l
c o n d i t i o n s , t h e r e s h o u l d be a
d e c r e a s e in o l d - n e w r e c o g n i t i o n
t i m e at t h e 350 a n d 1250 m s e c
c o n d i t i o n s in t h e S+R÷
c o n d i t i o n ( i e a f t e r the
a n a p h o r ) , but not in the S+R-
a n d S-R- c o n d i t i o n s , w h i c h are not a n a p h o r i o
2 T h e u s e of a d e f i n i t e n o u n
p h r a s e to r e f e r to a n
a n t e c e d e n t in the c a c h e (i.e
in focus) s h o u l d be d e t r i m e n t a l
to a n a p h o r a r e s o l u t i o n IZ
s h o u l d s l o w d o w n the
r e c o g n i t i o n of t h e r e f e r e n t as
o l d or new In t e r m s of the
e x ~ e r l m e n t a l c o n d i t i o n s , if the
r e f e r e n t is in focus, t h e
o l d - n e w r e c o g n i t i o n t i m e s in
t h e 3 5 0 a n d 1250 m s e c SOA
c o n d i t i o n s s h o u l d be s l o w e r
t h a n i n t h e b e f o r e S O A coD~Litlon
M e t h o d
E L T T J , ~ , p A ~ T h e r e
p ~ r t i o i p a n t s in t h i s study
w e r e 36
~ / ~ I ~ T h e r e w e r e 36
e x p e r i m e n t a l texts T h e y c o n t a i n e d as a
r e f e r e n t an i n s t a n c e of a c l ~ s s (e.g
t h e r m o m e t e r ) to be u s e d l a t e r as a test word, a n d a~ an a n ~ p h o r the c l a s s name (e.g i n s t r u m e n t ) In t h i s study, the
a n ~ p h o r w ~ s a d e f i n i t e n o u n phrase An
e x a m p l e of the m a t e r i a l was p r e s e n t e d in
T a b l e i T h e r e w e r e t h r e e p ~ i m l n g
o o n d l t l o n s , S+R+ S+R-, a n d S-R-,
Trang 85 a , 5b, a n d 50
D u r i n g t h e p r e s e n t a t i o n of e a c h
t e x t t w o or t h r e e t e s t w o r d s w e r e
p r e s e n t e d , o n e e x p e r i m e n t a l a n d o n e o r
t w o f i l l e r s T h e f i l l e r w o r d s w e r e
p r e s e n t e d at s e m i - r a n d o m l o c a t i o n s i n
t h e t e x t I n t h e e n t i r e e x p e r i m e n t
t h e r e w a s a n e q u a l n u m b e r of o l d a n d n e w
t e s t w o r d s
~ r ~ r e T h e e x p e r i m e n t w a s
c o m p u t e r - c o n t r o l l e d u s i n g r e a l - t l m e
r o u t i n e s o n t h e V A X / V M S 1 1 / 7 8 0 of t h e
C o m p u t e r L a b o r a t o r y f o r I n s t r u c t i o n i n
P s y c h o l o g i c a l R e s e a r c h at t h e U n i v e r s i t y
of C o l o r a d o E a c h p a r t i c i p a n t s a t in
f r o n t o f a C R T s c r e e n w i t h a k e y b o a r d
w h i c h h a d a "yes" b u t t o n o n t h e r i g h t
f o r o l d t e s t w o r d s , a n d a "no" b u t t o n o n
t h e l e f t f o r n e w t e s t w o r d s T h e t e x ~ s
w e r e p r e s e n t e d u s i n g R S V P w i t h e a c h
w o r d p r e s e n t e d i n t h e c e n t e r of t h e
s c r e e n f o r 3 0 0 m s e c T h e p a r t i c i p a n t s
w e r e a s k e d to r e c o g n i z e w h e t h e r t h e t e s t
w o r d s w e r e o l d or new a s f a s t as
p o s s i b l e but w i t h o u t m a k i n g m i s t a k e s
D ~ i ~ T h e r e w e r e 36 e x p e r i m e n t a l
t e x t s a n d 18 e x p e r i m e n t a l c o n d i t i o n s
T h e f i r s t m a n i p u l a t i o n w a s t h e f o c u s i n g
of t h e r e f e r e n t : i n f o c u s or n o t i n
f o c u s T h e s e c o n d m a n i p u l a t i o n w a s t h e
SOA: i m m e d i a t e l y b e f o r e ~ h e p r i m e 3 5 0
m s e c a f t e r 1 2 5 0 m s e c a f t e r T h e t h i r d
m a n i p u l a t i o n w a s p r i m i n g : S+R+ S+R-
S-R- T h e d e s i g n w a s c o m p l e t e l y
w i t h i n - s u b j e c t , w i t h t w o t e x t s r a n d o m l y
a s s i g n e d to e a c h e x p e r i m e n t a l c o n d i t i o n
u s i n ~ t w o r a n d o m l y s a m p l e d 18 b y 18
L a t i n S q u a r e s E a c h p a r t i c i p a n t w a s
r a n d o m l y a s s i g n e d to a r o w of t h e L a t i n
S q u a r e s
~ s u l ~ a a n d D ~ s c u s l ~
T h e p r e d i c t e d i n t e r a c t i o n of
f o c u s i n g a n d p r i m i n g is s h o w n i n F i g u r e
I: t h e p r i m e i n t h e S + R + c o n d i t i o n
(i.e t h e a n a p h o r ) r e i n s t a t e s t h e
r e f e r e n t i n t o t h e c a c h e , f o c u s i n g it
w h i l e ~ h e r e f e r e n t is n o t r e l n s t a z e d in
t h e n o n - r e f e r e n t l a l c o n d i t i o n s
E ( 2 7 0 ) = 3.6 ~ , 0.04 M S e = 2 1 3 ~ 2 1 b y
s u b j e c t s a n d E ( 2 7 0 ) = 2.5, ~ , O.Og,
M S e = 277568 b y items A p r i o r i
c o m p a r i s o n s s h o w t h a t t h e d i f f e r e n c e
b e t w e e n t h e r e c o g n i t i c n t i m e s i n t h e t w o
f o c u s c o n d i t i o n s in ~ h e S ¢ R + c o n d i t i o n
is m u c h s m a l l e r t h a n i n t h e o t h e r t w o
p r i m i n g c o n d i t i o n s , S - R - a n d S-R- w h i c h
d o m o t d i f f e r b e t w e e n t h e m s e l v e s ,
~ ( 3 5 ) ° 2 6 ~ , 0.01 M S e - 87 b y
s u b j e c t s , a n d ~ ( 3 5 ) = 2.14 ; , 0 0 2 ,
M S e = 114 b y i t e m s T h e s e r e s u l ~ s
s u p p o r t t h e n o t i o n s t h a t i ~ e m s i n f o c u s
a r e m o r e a c c e s s i b l e t h a n i t e m s n o t i n
t h e c a c h e T h e y a l s o s u p p o r t t h e n o t i o n
t h a t a n a n a p h o r r e i n s t a t e s a r e f e r e n t
n o t i n f o c u s a n d d o e s so b y t r a n s f e r r i n g
t h e r @ f e r e n t t o t h e c a c h e
L
A
T
E
N
C
I
E
S
(msec)
F I G U R E I
1345
1305
1185
1145
1105
1065
1025
S + R + S * R - S - R -
P R I M I N G
R e c o g n i t i o n l a t e n c i e s az e a c h
f o c u s a n d p r i m i n g c o n d i t i o n
A n a p r i o r i c o m p a r i s o n d e m o n s t r a t e s
t h a t u s i n g a d e f i n i t e n o u n p h r a s e ~o
r e f e r to a n i t e m in f o c u s h i n d e r s
a n a p h o r a r e s o l u t i o n W h a t s e e m s ~o
h a p p e n is a s u r p r i z e e f f e c t c a u s e d b y
t h e v i o l a t i o n of a l i n g u i s t i c u s a g e
r e l a t i n g t h e f o r m of t h e a n a p h o r to t h e
f O C U S S ~ a t u s of i t s r e f e r e n t T h e
r e c o g n i t i o n t i m e f o r t h e r e f e r e n t , i n
t h e f o c u s c o n d i t i o n , w a s l o n g e r at t h e
3 5 0 m s e c a n d 1 2 5 0 m s e c S O A s t h a n i n t h e
b e f o r e SOA ~ ( 3 5 ) - -4.1 R ~ 0 0 0 1
M S e - 2 4 b y s u b j e c t s , a n d ~ ( 3 5 ) - -2.9, , 0 0 0 8 M S e - 31 b y i t e m s T h i s is
s h o w n i n F i g u r e 2
L 1345
A 1305-
T
E 1265-
N
C 1225-
I 1185-
E (msec) 1105- 1065-
1025 • before 350 1250 SOA
F I G U R E 2
( ~ s e c )
R e c o g n i t i o n l a ~ e n c i e s a~ e a c h
S O A f o r a r e f e r e n t i n f o c u s
Trang 9u s i n g ~he s a m e o n - l l n e ~ c ~ i v a ~ i o n
t e c h n i q u e , the ~ c ~ i v a t i o n of a n
a n t e c e d e n t b y a p r o n o u n was ~raced In
t h i s study, it was fo%L~d tha~ r e f e r r i n g
~o a n a n t e c e d e n ~ not in focus b y u s i n g a
p r o n o u n was d e t r i m e n t a l to a n a p h o r a
r e s o l u t i o n T h e d e l a y b e t w e e n r e a d i n g
the a n a p h o r a n d r e i n s ~ a t l n g the
a n ~ e c e d e n ~ w a s as l o n g as 2 4 0 0 msec
T h e a c t l v a ~ i o n of a n a n t e c e d e n ~ no~ in
f o c u s b y a p r o n o u n t a k e s a l o n g ~ i m e
b e c a u s e ~he r e a d e r is induced: I) to
s e a r c h t h e c a c h e u n s u o c e s f u l l y ; 2) to
s e a r c h o p e r a t i n g m e m o r y w i t h a "sketchy"
p r o n o u n : 3) to r e l n s t a Z e the r e f e r e n t
i n t o the cache A c t i v a t i o n was
i m m e d i a t e for ~he a n t e c e d e n t s in focus
As o p p o s e d ~o the p r e v i o u s s ~ u d y w h e r e
r e f e r r i n g to a f o c u s e d r e f e r e n ~ u s i n g a
d e f i n i t e n o u n p h r a s e h i n d e r e d a n a p h o r a
r e s o l u t i o n , no s u c h e f f e c t was o b s e r v e d
w h e n u s i n g a pronoun T h i s is e x p e c t e d
s i n c e p r o n o u n s s i g n a l tha~ ~he r e f e r e n t
is in the cache
S U M M A R Y
T h e n o t i o n of f o c u s i n g a n d the
n o t i o n that the f o r m of the a n a p h o r
s i g n a l s w h e t h e r ~he r e f e r e n ~ is in f o c u s
or no~ h a v e c o g n i t i v e support I t e m s in
f o c u s are i t e m s in the c a c h e w h i c h is
d y n a m i c a l l y u p d a t e d ~o c o n t a i n ~he T
most ~ o p i c a l a n d t h e R most r e c e n ~ i t e m s
in the ~ex~ B e c a u s e the c a c h e c o n ~ a l n s
few items, p r o n o u n s s h o u l d be u s e d ~o
r e f e r to i t e m s in focus O ~ h e r t h i n g s
b e i n g equal, a n a p h o r a r e s o l u t i o n w i l l be
e a s i e r if the a n t e c e d e n t is in focus,
b e c a u s e ~he r e t r i e v a l ~ i m e s f r o m the
c a c h e are m u c h f a s t e r ~ h a n t h o s e from
the o p e r a t i n g memory A n t e c e d e n t s not
in f o c u s are in o p e r a t i n g memory I ~ e m s
no~ in f o c u s are in o p e r a t i n g memory A
d e f i n i t e n o u n phrase, b e c a u s e it is m o r e
d e s c r i p t i v e ~ h a n a pronoun, s h o u l d b e
u s e d to r e ~ r i e v e the ~ n t e c e d e n ~ f r o m ~ h e
l a r g e set of i ~ e m s in o p e r a t i n g memory
H o w e v e r , b e c a u s e ~he r e E r l e v a l ~ i m e is
s l o w in o p e r a ~ i n ~ memory, a n a p h o r a
r e s o l u t i o n is m o r e d l f f l c u l ~ for i ~ e m s
r e l n s ~ a ~ e m e n ~ of a m a n ~ e c e d e n ~ i n t o ~ h e
c a c h e e f f e c t s a ~ o p l c shift
The o n - l l n e a c t i v a t i o n ~ e c h n i q u e
was d e v e l o p e d s p e c i f i c a l l y to p r o v i d e
e m p i r i c a l d a t a on the n o ~ i o n of focus
The ~ d v a n ~ a g e of this t e c h n i q u e over
c o n v e n t i o n a l m e m o r y e x p e r i m e n t s is that
one c a n ~est p r e c i s e l y the ~ e m p o r a l
p r o p e r t i e s of v a r i o u s a n a l y s e s a n d
p r o c e s s e s o c c u r r i n g d u r l n ~ s e n t e n c e and
ter~ c o m p r e h e n s i o n This t e c h n i q u e can
be u s e d to d i s t i n g u i s h b e t w e e n d i f f e r e n t
m o d e l s of a n a p h o r a r e s o l u t i o n w h e n ~ h e s e
m o d e l s are no~ e a s i l y d i s t i n g u i s h e d on
t h e b a s i s of d i s c o u r s e or d i a l o g u e
a n ~ i y s l s
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A C K N O W L E D G M E N T
T h l s r e s e a r c h was p e r f o r m e d as par% of the a u Z h o r ' s d o c t o r a l d i s s e r t a t i o n w h i l e a~ ~he U n i v e r s i t y of Colorado She is
e x % r e m e l y g r a t e f u l for ~he h e l p of her
d i s s e r t a t i o n oommlZ~ee W a l ~ e r EinZsch
P e t e r Polson, Alice Healy R i c h a r d Olson AndrzeJ Ehrenfeuch~ B u r % o n
W a g n e r has p r o v i d e d m a n y i n s i g h t f u l
c o m m e n t s on this paper M C C is k i n d l y
~ h a n k e d for ~he t e c h n l c a l s u p p o r %
p r o v i d e d w h i l e o o m p o s l n g ~hls paper