BRIDGING' 
Herbert H. Clark 
Stanford University 
Nixon, not long before he was deposed, 
was quoted as saying at a news conference, 
"I am not a crook." We all saw immediately 
that Nixon shouldn't have said what he said. 
He wanted to assure everyone that he was an 
honest man, but the wording he used was to 
deny that he was a crook. Why should he 
deny that? He must have believed that his 
audience was entertaining the possibility 
that he was a crook, and he was trying to 
disabuse them of this belief. But in so 
doing, he was tacitly acknowledging that 
peoplewere entertaining this possibility, 
and this was something he had never 
acknowledged before in public. Here, then, 
was a public admission that he was in 
trouble, and this signaled a change in his 
public posture. My inferences about Nixon's 
ubterance stopped about there, but I am sure 
that the knowledgeable White House press 
corps went on drawing further inferences. 
In any event we all took this utterance a 
long way. 
This is an example par excellence of a 
basic problem for theories of understanding 
natural language: How do listeners draw 
inferences from what they hear, what 
direction do they take their inferences, and 
when do they stop? In this particular 
example, at least most listeners began, 
tacitly, drawing the same llne of 
inferences, but at a certain point, the 
lines diverged and went on to many different 
stopping points. But is this description 
general? Could listeners go on drawing 
inferences ad infinitum? And ultimately, is 
drawing inferences as a part of 
comprehension a describable process, one 
with specifiable constraints? 
In this brief paper I would llke to 
discuss a certain class of inferences in 
comprehension that may provide some general 
lessons about the problem of drawing 
inferences. The inferences I will discuss 
are ones the speaker intends the listener to 
draw as an integral part of the message, and 
so they are a rather special type. 
Following Grice's (1967) terminology, I will 
refer to them as implieatures, since they 
have all the characteristics of other 
implicatures. I will draw three lessons 
about these implicatures. One: Implicatures 
of this kind originate in an implicit 
contract, of quite a specific sort, that the 
speaker and listener have agreed upon about 
the way they are to converse with each 
other. TWO: These implicatures, though 
conveyed by language and a necessary part of 
the intended message, draw on one's 
knowledge of natural objects and events that 
goes beyond one's knowledge of language 
itself. Three: These implicatures are not 
indeterminate in length, but have a 
well-defined stopping rule. 
Giveq-New Co~tr~ot 
169 
The implicatures I am concerned with 
are a consequence of a speaker-listener 
agreement Susan Haviland and I have called 
the Given-New Contract (Clark and Haviland, 
1974, in press; Haviland and Clark, 1974). 
English assertions draw a distinction 
between two kinds of information they 
convey, a distinction carried by the syntax 
and intonation alone. The first kind of 
information has been called Given 
information, since it is conventionally 
required to convey information the listener 
already knows; and the second kind has been 
called New information, since it is 
conventionally required to convey 
information that the listener doesn't yet 
know but that the speaker would like to get 
across. The point is, the Given-New 
distinction is a syntactic one, identifiable 
for sentences in isolation, and yet it 
serves a pragmatic function, that of 
conveying two types of information as far as 
the listener is concerned. For this 
distinction to be useful as a communcative 
device, therefore, the speaker and listener 
must agree to use it in the conventional 
way. The speaker must agree to try to 
construct his utterances so that the Given 
information contains information he believes 
the listener already knows and so that the 
New information contains information he 
believes the listener doesn't yet know. The 
listener, for his part, agrees to interpret 
each utterance on the assumption that the 
speaker is trying to do this. 
Consider the sentence It was M~rY who 
~e~t. Syntactically, it is Given that 
someone left, that is, X left, and it is New 
that that someone was Mary, that is, X = 
Mary. To deal with this sentence, the 
listener is assumed to use the following 
strategy. (I) He identifies the Given and 
the New. (2) He realizes he is expected to 
know already about a unique event of someone 
leaving, and so he searches back in memory 
for Just such an event. When he finds it, 
say E~I left ("some entity labeled E31 
left"), he calls this the Antecedent. (3) 
Since the listener assumes that X left was 
meant to refer to the Antecedent E~I left, 
he then replaces ~ in ~ ~ Mary by E31 to 
form the new proposition E31 ~ Mary. This 
he places in memory as what the speaker 
meant to assert in his utterance. 
In the simplest case, the strategy Just 
given will work without problems. Consider 
sequence I: 
I. John saw someone leave the party 
early. It was Mary who left. To simplify 
things, imagine that the listener hearing 
the second sentence has in episodic memory 
only the information conveyed by the first. 
In applying his strategy to the second 
sentence, the listener will search for an 
Antecedent for X left, find an event of 
someone leaving in memory from the first 
sentence, and then integrate the New 
information into memory as he should. 
In the more typical case, however, the 
Istener will fall at Step 2 of the strategy 
-- he won't find such an Antecedent directly 
in memory. When this happens, he is forced 
to construct an Antecedent, by a series of 
inferences, from something he already knows. 
Consider sequence 2: 
2. In the group there was one person 
missing. It was Mary who left. In this 
sequence the first sentence doesn't mention 
anyone s leaving, so there is no direct 
Antecedent for the Given information X left 
of the second sentence. The listener must 
therefore bridge the gap from what he knows 
to the intended Antecedent. He might note 
that it would follow that one person in the 
group would be missing if that person had 
left. It must be that the speaker was 
referring to that person by the Given 
information X l~ft and that the listener was 
supposed to figure this out by drawing this 
inference. In short, the listener assumes 
the speaker meant to convey two things: (I) 
the implicature The Q~e person was missin~ 
because that person left, and (2) the latter 
clause contains the intended Antecedent of 
the Given information in the second sentence 
l~ft. 
In its most general form, then, the 
Given-New Contract goes something llke this: 
Given-New Contract: The speaker agrees 
to try to construct the Given and 
New information of each utterance in 
context (a) so that the listener is 
able to compute from memory the 
unique Antecedent that was intended 
for the Given information, and (b). 
so that he will not already have the 
New information attached to the 
Antecedent. 
The listener in turn knows, then, that the 
speaker expects him to have the knowledge 
and mental wherewithal to compute the 
intended Antecedent in that context, and so 
for him it becomes a matter of solving a 
problem. What bridge can he construct (I) 
that the speaker could plausibly have 
expected him to be able to construct and (2) 
that the speaker could plausibly have 
intended? The first part makes the listener 
assess principally what facts he knows and 
the second what impllcatures he could 
plausibly draw. 
Bridging -- the construction of these 
implicatures -- is an obligatory part of the 
process of comprehension. The listener 
takes it as a necessary part of 
understanding an utterance in context that 
he be able to identify the intended 
referents (in memory) for all referring 
expressions. All referring expressions are 
Given information, and so the listener feels 
it necessary to succeed in applying the 
strategy outlined above, since it identifies 
the intended referents. In most instances, 
the success of this strategy requires the 
listener to bridge, to construct certain 
implicatures, and so he takes these 
implicatures too as a necessary part of 
comprehension. In short, he considers 
implicatures to be intrinsic to the intended 
message, since without them the utterance 
could not refer. 
17o 
Varieties of Imp~icature 
Bridging from previous knowledge to the 
intended Antecedent can take many forms. I 
will here give a brief taxonomy of bridges I 
have found in naturally occurring discourse. 
As before I will illustrate the bridges with 
two sentence sequences in which the first 
constitutes the entire episodic knowledge 
available for bridging to the second. What 
I say here, however, is meant to apply just 
as much to episodic information derived from 
non-llnguistlc sources; the two-sentence 
sequences are just an expositional gimmick. 
One more caveat. As with any taxonomy, this 
one is hardly complete. Indeed, it cannot 
be until one has a theory to account for the 
taxonomy itself. 
Dire~t re~erence. Given information 
often makes direct reference to an object, 
event, or state Just mentioned. These 
always force an implicature of some sort, 
even though it may be trivially simple. 
This class of bridging is well known: 
Identity: 
I. I met a man yesterday. The man 
told me a story. 
2. I ran two miles the othe# day. 
The run did me good. 
3. Her house was large. The size 
surprised me. 
Pronominali~ation: 
4. I met a man yesterday. He told 
me a story. 
5. I ran two miles the other day. 
It did me good. 
6. Her house was large. That 
surprised me. 
Epithets: 
7. I met a man yesterday. The 
bastard stole all my money. 
8. I ran two miles the other day, 
The whole stupid business bored me. 
9. Her house was large. The 
immensity made me Jealous. 
The implicature for these direct 
references is straightforward. For the 
identity in I, the implicature is 
approximately this: 
I ° . The Antecedent for the man is 
the entity referred to by "a man". 
This implicature, though obvious, must be 
drawn for the second sentence in I to be 
complete; conceivably, ~_g man could have 
referred to some other object, and so the 
listener is making a leap -- perhaps only a 
millimeter leap -- in drawing this 
implicature. The same implicatures arise in 
2 and 3. As for the pronominallzation in 4, 
the principle is the same, but the pronoun 
(he) uses only a subset of the properties 
that characterize the previously mentioned 
man. Indeed, there is a continuum of 
pronominalization, as for the noun phrase an 
elderly ~: ~he el der~y ~leman, 
the elderly man, ~he ~, the ~, the 
oldster, the adult, the oerson, and he. The 
I 
I 
I 
I 
I 
I 
I 
! 
I 
I 
I 
I 
I 
I 
I 
I 
I 
I 
I 
"pronouns" here range from full to sparse 
specification, but otherwise work like I and 
I". The epithets, on the other hand, add 
information about the referent, as in the 
implicature for 7: 
7". The antecedent for the bastard 
is the entity referred to by "a 
man"; that entity is also a bastard. 
Epithets are surprisingly restricted in 
productivity, for not Just anything will do, 
Replace the bastard in 7 by the rancher, or 
even by the robber, and the bridging doesn't 
go through; the cancher and robber seem ,to 
refer to someone other than the man. 
One can also make direct reference to 
one or more members of a set, as in these 
examples: 
Set membership: 
10. I met two people yesteday. The 
woman told me a story. 
11. I met two doctors yesterday. 
The tall one told me a story. 
12. I swung three times. The first 
swing missed by a mile. 
Here the Given informaion has an Antecedent 
that must be picked out uniquely from a 
previously mentioned set, and to pick it 
out, one must draw an implieature with 
several parts. For 10, the implicature is 
approximately this: 
10". One of the entities referred to 
by "two people" is a woman and the 
other is not; this woman is the 
Antecedent of the woman. 
The listener of 10 infers that the other 
person is not a woman since that is the only 
way the speaker could have picked out "the 
woman" uniquely. There are similar 
implicatures for 11 and 12. 
Indirect reference by association. 
Given information often has as its 
Antecedent some piece of information not 
directly mentioned, but closely associated 
with the object, event, or situation 
mentioned (see Chafe, 1972). These 
"associated" pieces of information vary in 
their predictability from the object, event, 
or situation mentioned -- from absolutely 
necessary to quite unnecessary -- although I 
will list only three levels: 
Necessary Darts: 
13. I looked into the room. The 
ceiling was very high. 
14. I hit a home run. The swing had 
been a good one. 
15. I looked into the room. The 
size was overwhelming. 
In 13, since all rooms have ceilings, and 
only one ceiling each, the ceiling can be 
definite with the following implicature: 
13". The room mentioned has a 
ceiling; that ceiling is the 
Antecedent of the ceiling. 
Next consider associated parts that are 
only probable: 
171 
Probable parts: 
16. I walked into the room. The 
windows looked out to the bay. 
17. I went shopping yesterday. The 
walk did me good. 
18. I left at 8 p.m. The darkness 
made me jumpy. 
There is no guarantee that the room has 
windows, that going shopping means walking, 
or that it is dark at 8 p.m., but these are 
all probable or at least reasonable. The 
implicature of 16 is simply this: 
16". The room mentioned has windows; 
they are the Antecedent for the 
windows, 
There are, however, associated parts 
that one would normally not think of and are 
only induced by the need for an Antecedent: 
Inducible p~rts: 
19. I walked into the room. The 
chandeliers sparkled brightly. 
20. I went shopping yesterday. The 
climb did me good. 
21. I left at 8 p.m. The haste was 
necessary given the circumstances. 
Here we come to infer that the room had 
chandeliers, that going shopping included 
some climbing, and that the departure at 8 
p.m. was hasty, but these were certainly 
not necessary parts of these objects, 
events, or states. For 19, the implicature 
would be this: 
19". The room mentioned had 
chandeliers; they are the Antecedent 
for the ~. 
Here, then is a clear case in which the 
search for an Antecedent induced the 
proposition that a particular part must be 
present. In normal comprehension, after 
reading ~ walke~ into ~he room, we wouldn't 
spontaneously think of a chandelier in the 
room. The first part of 19" clearly only 
arises because of the second sentence in 19. 
On the other hand, notice that 19" is an 
implicature of precisely the same form as 
16". It is Just that the first half of the 
implicature in 19" cannot be assumed either 
automatically or even probably. 
Indirect reference by characterization" 
Often the Given information characterizes a 
role that something implicitly plays ~ in an 
event or circumstance mentioned before, and 
these have a tremendous variety. First 
there are the necessary roles: 
e es~ roles: 
20. John was murdered yesterday. 
The murderer got away 
I ~ " 21. went shopping yesterday. The 
time I started was 3 p.m. 
22. I trucked the goods to New York. 
The truck was full. 
The implicature for these is uncomplicated, 
as illustrated for 20: 
20". Some one person performed 
John's murder; that person is the 
Antecedent for the murderer. 
The first sentence in 20 does not claim that 
there was only one murderer, but the second 
sentence forces this implicature. 
Similarly, the verb trucked in 22 doesn't 
say there is only one truck, but the second 
sentence, as part of its implicature, forces 
this to be the case. 
Then come the strictly optional roles: 
Optional rolgs: 
23. John died yesterday. The 
murderer got away. 
24. John was murdered yesterday. 
The knife lay nearby. 
25. John went walking at noon. The 
park was beautiful. 
In 23, the implicature is something like 
this: 
23". Some one person caused John to 
die; that one person is the 
Antecedent of the murderer. 
In 24, the implicature is that John was 
stabbed to death with a knife, the 
instrument referred to by the knife, and in 
25 the implicature is that where Jo~n went 
walking was in a park, the place referred to 
by the park. 
These two categories -- necessary and 
optional roles -- cover a lot of ground. 
Most noun phrases, for example, are 
characterizing, in that they contain as Raft 
of their specification how they relate to 
other events. I have given unadorned noun 
phrases here, but of course they can become 
quite elaborate. The murderer could have 
been the person whQ murdered John; the 
knife, which is implicitly defined as a 
tool, could have been t~e knife with which 
it was do~e; and so on. English contains a 
range of cleft and pseudo-cleft sentences 
that often fill Just this purpose, as in The 
one that murdered John £o~ away, and It was 
that man who murdered John. Adjectives can 
carry out this characterizing funcion too, 
as in The gqiltv party g_q~ away. What these 
adjectives (e.g. ~uiltv), relative clauses 
(e.g. th~$ murdered John), and derived 
nouns (e.g. the murderer) do is pick out 
the role the intended Antecedent plays in 
the previously named events. 
It is not easy to separate "parts" from 
"roles" in every instance. For example, the 
knife in 24 is conceived of not as a part of 
the action of murdering, as, say, "stabbing" 
would be, but rather as a role in the 
action, as an instrument. I have considered 
the word knife to have implicit within it 
the notion that it is an instrument, so it 
is a characterizing noun, like murderer, not 
simply a name of a non-functional class llke 
man. Ultimately, however, this distinction 
may be impossible to maintain. 
Reasons. causesL conseouences. ~q~ 
concurrences. The Antecedent to the Given 
information of a sentence is often an event 
and not an object, and then it plays 
different types of rols with respect to 
previous events. Instead of being agents, 
objects, or instruments characterized with 
respect to previously mentioned events, this 
172 
class of Antecedents gives reasons for, 
causes of, consequents to, or concurrences 
of previously mentioned events or states. 
The first class are reasons: 
Reasons: 
26. John fell, what he wanted to do 
was scare Mary. 
27. John came to the party. The one 
he expected to meet was Mary. 
28. John had a suit on. It was Jane 
he hoped to impress. 
In each case the Antecedent of the Given 
information in the second sentence is 
contained in a reason for the first event. 
So the implicature for 26 is something like 
this: 
26". John fell for the reason that 
he wanted to do something; that 
something is the Antecedent to what 
he wanted t_go do. 
Reasons • always answer the question "what 
for?" and the Antecedents in 26 through 28 
all make use of this kind of reason to 
bridge from the first sentence's event or 
state. 
Unlike reasons, causes answer the 
question "How come?" 
C~qses: 
29. John fell. What he did was trip 
on a rock. 
30. John came to the party. The one 
who invited him was Mary. 
31. John had a suit on. It was Jane 
who told him to wear it. 
The implicature in 29 goes something like 
this: 
29". John fell because he did 
something; that something is the 
Antecedent for what he dld. 
This type of implicature works for 30 and 31 
as well. In each case we infer a causal 
relation between the event presupposed by 
the Given information of the second sentence 
and the event mentioned in the first 
sentence. 
Then there are consequences: 
Conseouences: 
32. John fell. What he did was 
break his arm. 
33. John came to the party early. 
The one he saw first was Mary. 
34. John met Sally. What he did was 
tell her about Bill. ' 
The approximate implicature for 32 is as 
follows: 
32". John did something because he 
fell; that something is the 
Antecedent to what he did. 
The sequences in 33 and 34 have similar 
implicatures, ones that also depend on the 
Antecedent's being taken as the consequence 
of the event mentioned in the first 
I 
1 
I 
i 
i 
I 
i 
i 
il 
! 
II 
i 
| 
I 
| 
I 
I! 
ii 
i 
sentence. 
Last of all are the concurrences: 
ConcurreDces: 
33. John is a Republican. Mary is 
slightly daft too. 
34. John is a Republican. Mary 
isn't so smart either. 
35. Alex went to a party last night. 
He's going to get drunk again 
tonight. 
For 33 the implicature is approximately this 
(see Lakoff, 1971): 
33". All Republicans are slightly 
daft; therefore, John is slightly 
daft, which is the Antecedent to the 
Given information someone other than 
Mary is slightly daft. 
In all three of these sequences, the 
listener is expected to draw the implicature 
that being in one state, or doing one event, 
necessarily entails the concurrence of 
another state, or event. 
These are four general ways, then, in 
which the listener can bridge from an event 
or state mentioned in the first sentence to 
an Antecedent in the second. These bridging 
relations turn out to be very common~ 
especially in narratives. The most common, 
perhaps, is the consequence, which pops up 
between one sentence and the next every time 
chronological order is conveyed. The Given 
information of the second sentence is taken 
as a consequence to the event mentioned in 
the first. 
Det~rmlnacv in~/.l~ 
In principle, bridges need. not be 
deteminate. One could, if one had the time 
and inclination, build an infinitely long 
bridge, or sequence of assumptions, to link 
one event to the Antecedent of the next. In 
35, for example# we assumedthat every time 
Alex goes to a party he gets drunk. But we 
could have assumed instead that every time 
he goes to a party he meets women, and ,all 
women speak in high voices, and high voices 
always remind him of his mother, and 
thinking about hhs mother always makes him 
angry, and whenever he gets angry, he gets 
drunk, It takes very llttle imagination to 
add span after span to a bridge of this 
type. 
Yet in a natural discourse, bridges are 
always determinate. Indeed, I suggest that 
they have a stopping rule that goes 
something llke this: Build the shortest 
possible bridge that is consistent with the 
Given-New Contract. The listener assumes, 
based on this contract, that the speaker 
intended him to be able to compute a unique 
bridge from his previous knowledge to the 
intended antecedent of the present Given 
information. If the speaker was certain 
that the listener could do this, he must 
have intended the listener to take the 
shortest possible bridge consistent with 
previous knowledge, for that would make the 
bridge unique, as required. So in 35 the 
listener assumes the speaker intended him to 
infer no more than that every time Alex goes 
173 
to a party he gets drunk, for this 
implicature makes the fewest assumptions yet 
is consistent with previous knowledge of 
parties; dringking, and even Alex. In 
short, the listener takes as the intended 
implicature the one that requires the fewest 
assumptions, yet whose assmptions are all 
plausible given the listener's knowledge of 
the speaker, the situation, and facts about 
the world. 
The implicatures I have discussed here 
differ from the inferences we drew from 
N!xon's "I am not a crook" in one important 
way. The implicatures I took up were 
intended bythe speaker to be constructed by 
the listener, whereas the inferences from 
Nixon's blunder were not. With the 
implicatures, as with every other intended 
meaning, the speaker had a unique bridge in 
mind, and so the listener had something 
unique to try to figure out. But for 
Nixon's bobble, after the first unique and 
legitimate inference -- denials presuppose 
that the audience does or could believe what 
iS being denied -- the inferences were 
completely unauthorized by the speaker. So 
bridging is determinate with a definite 
stopping rule, whereas Unauthorized 
inferences typically are not. 
This brings US, finally, to the issue 
of forward vs. backward inferences. When 
we hear the phrase the room in 19, we may 
begin imagining all sorts of things about 
this room, some necessary, but many others 
optional. All but the necessarylnferences 
here, of course, are unauthorized. . These 
"forward" inferences differ radically from 
the "backward" inferences forced by the 
phrase the f~ in 19, for the speaker 
intended the listener to infer that the room 
had a chandelier. Both types of inferences 
occur, I'm sure, but only the latter type 
are fully determinate, I suggest that we 
might do well to study the determinate 
Inferences first, for'they may well give us 
a clue as to what sorts of unauthorized 
Inferences would be likely to be drawn for 
the typical utterance. 
REFERENCES 
Chafe, W. Discourse structure and human 
knowledge. In J.B. Carroll and R.O. 
Freedle (eds.), LanRua~e ComDrehenslon 
and the ~ of Knowledg@. 
Washington: Winston and Sons, 1972. 
Clark, H.H., and Haviland, S.E. 
Psychological processes as llnguistic 
explanation. In D. Cohen (ed.), 
~ Phenomena. 
Washington: Hemisphere Publishing Corp., 
1974. 
Clark, H.H. and Haviland, S.E. 
Comprehension and the Given-New 
Contract. In R. Freedle (ed.) 
Discourse ~ and ~/I~U~. 
Hillslde NJ: Lawrence Erlbaum 
Associates, in press. 
Haviland, S.E. and Clark, H.H. What's new? 
Acquiring new information as a process 
in comprehension. Journal of Verbal 
Learning and Verbal Behavior, 1974, I~, 
512-521. 
Grice, H.P. Logic and conversation. 
William James Lectures, Harvard 
University, 1967. In P. Cole and J.L. 
Morgan (eds.), Studies in SYntax, Volume 
III. New York: Seminar Press, 1975. 
Lakoff, G. The role of deduction in 
grammar. In C.J. Fillmore and D.T. 
Langendoen (eds.), Studies 'in 
Linguistics Semantics. New York: Holt, 
Rinehart and Winston, 1971. 
174 
