Lexical marking of discourse relations - some experimental 
findings 
Claudia Sofia 
University of Pisa 
Department of Linguistics 
Via S.Maria 36 - 56126 Pisa - Italy 
e-mail soria~ling.unipi.it 
Giacomo Ferrari 
University of East Piemonte 
Department of Human Studies 
Via G.Ferraris 109 - 13100 Vercelli- Italy 
e-mail ferrari@zeus.vc.unipmn.it 
Abstract 
Both in written and in spoken language, discourse 
relations may or may not be signalled by lexical ma- 
terial. In this paper we present the results of two 
experiments which were intended to answer some 
questions concerning the relationship between dis- 
course relations and their lexical markers. Assuming 
that, in any case, discourse relations are inferred by 
the addressee/interpreter, the question arises about 
what suggests to the speaker/writer the strategical 
decision of using rather than not using explicit sig- 
nals, such as connectives or cue phrases. In order to 
answer this main question, the following subques- 
tions need to be answered: first, which role do dis- 
course markers play in the task of reconstructing the 
discourse relation which was originally intended by 
the speaker/writer. Second, to what extent the lexi- 
cal signalling of the relation is essential for the rela- 
tion to be inferred. Third, whether there are coher- 
ence relations that are always lexically signalled and 
whether there are any that are never lexically sig- 
nalled. Finally, if the different access that addressees 
have to the linguistic context in spoken and written 
language affects the kind of relations employed in 
the construction of text and/or in the realization of 
the relations. 
1 Discourse Relations 
Discourse relations have been addressed by a number 
of different approaches for the purposes of text un- 
derstanding, text analysis and text planning. This 
results not only in a difference in the theoretical 
interpretations of the concept, but also in a het- 
erogeneity among the actual sets of relations which 
are assumed to be psychologically and/or descrip- 
tively adequate. On the other hand, the various ap- 
proaches show a considerable overlap in the individ- 
ual relations adopted, thus suggesting a "commOn 
ground" shared by all approaches. For the aims of 
our research, rather than committing to one or an- 
other interpretation of discourse relations, we have 
abstracted from the various taxonomies three broad 
classes or types of relations, namely an additive type, 
a consequential type, and a contrastive type. These 
three classes are identified on the ground of the basic 
cognitive operation which is implied in the instanti- 
ation of a connection between adjacent segments of 
discourse. 
Additive relations share the common feature of 
implying some kind of similarity between the seg- 
ments they relate. We conceive the notion of simi- 
larity in a broad sense, so that an additive relation 
is supposed to hotd when 
a) p(x) can be inferred from the assertion of $1 
and p(y) can be inferred from the assertion of 
S2,where x and y belong to a similar class of 
entities. For example: 
1. The French proposal to invoke the 
right to self-determination of that pop- 
ulation having been rejected ($I), also 
the idea of a military intervention has 
been abandoned ($2). 
b) p(X) can be inferred from the assertion of 5'1 
and p(x) can be inferred from the assertion of 
$2, where x is a member or subset of X (as for 
specification or exemplification). For example: 
36 
2. In spite of their unwelcom- 
ing appearance, the islands off Kerry 
have been once inhabited ($1). Skel- 
lig Michael, for instance, hosted a 
monastery in the VI century ($2). 
c) p(x) can be inferred from the assertion of St and 
p(X) can be inferred from the assertion of S~, 
where x is a member or subset of X (opposite 
case of generalization). For example: 
3. Phil is 6 feel tall (S1). All the men 
in my family are tall ($2). 
d) p(x) can be inferred from the assertion of $1 
and p(x) can be inferred from the assertion of 
$2 (that is, the "same" proposition can be in- 
ferred from the assertion of the two segments; 
this class concerns reformulations and correc- 
tions). For example: 
4. One of the central notions of neu- 
rophysiology is that neurons work in 
"frequency modulation" ($I). That 
is, they exchange signals by increasing 
or decreasing the frequency of nervous 
impulses ($2). 
e) p(x) can be inferred from the assertion of $1 
and q(x) can be inferred from the assertion of 
$2. This class concerns those cases generally 
identifiable as "continuation", as in 5, as well 
as instances of "alternative", as in 6: 
5. In 17.32 Tiepolo was in Bergamo, 
painting Colleoni chapel; he received, 
then, important commissions for the 
venetian churches ($1) and dedicated 
himself to the decoration of palaces 
and villas of the high venetian aristoc- 
racy (s2). 
6. Pursuing the desire of a better feel- 
ing, one smokes ($1) or keeps swallow- 
ing drugs ($2}. 
f) p(x) can be inferred from the assertion of St and 
q(y) can be inferred from the assertion of S.2, 
where x and y are connected by one of the fol- 
lowing relations (cf. van Dijk, 1977): whole- 
part, including-included, possessor-possessed, 
outside-inside, Figure-ground (cf. Hobbs, 1985; 
1990), as in 
7. They climbed upon the hill ($I). In 
the distance they could see the line of 
the sea ($2). 
and script-based relations, as in the two follow- 
ing examples: 
8. Paul is a doctor (SI). The children 
are three and five years old ($2). 
9. The effect is guaranteed (SI) and 
the pureness increases the risks of 
overdose ($2). 
Generally speaking, the additive class of relations 
covers Hobbs" Parallel, Elaboration, Exemplifi- 
cation and Generalization relations (of. Hobbs 
1985; 1990), Mann and Thompson's Sequence, 
Elaboration, Joint, Summary, Restatement 
and Interpretation relations (cf. Mann and 
Thompson, 1986; 1988); it also embraces the re- 
lations List and Enumeration of (Sanders et al., 
1993). 
Typical markers of the additive type are and, or, or 
else, in other words, that is, or better, I mean, in 
addition, also, alternatively, for example, etc. 
Consequential relations share the common fea- 
ture of establishing an implication or a dependence of 
some kind (causal, temporal, modal, concessive, hy- 
pothetical, etc.) between the segments they relate. 
Iu all the relations belonging to this class the infor- 
mation (or the content) that can be inferred from $1 
implies the information (or the content) that can be 
inferred from 5"2 (or vice versa). More precisely, p 
can be inferred from the assertion of $1 and q can be 
inferred from the assertion of S2, and p implies q or 
vice versa, from a point of view which can be causal, 
temporal, modal, hypothetical, etc. Some examples, 
representative of the different kinds of implication, 
are the following: 
10. If you want to work (S1), the more 
you look lean and pale the more they think 
you're wonderful ($2). 
11. We should reckon with the resources we 
dispose of, because no one would accept to 
go to the moon with a bycicle (SI). It is a 
question, thus, of attentively evaluating the 
appropriateness of the means in regard to 
the target ($2). 
12. Preparing jams, marmalades and jel- 
lies, to be consumed in the winter and to be 
proudly offered to friends, can be a pleasant 
and relaxing pastime ($1). The operation, 
although beginners may think is very com- 
plex, does not present, in fact, any partic- 
ular difficulty ($2). 
37 
13. From I750 to 1753 he was already 
working out of Italy in W~rzburg, at the 
residence of the prince-bishop ($1); finally 
he left to Madrid, where he spent the last 
eight years of his life concentrating upon 
the frescos of the royal palace ($2). 
Typical markers are because, so, so that, thus, as 
a consequence, as a result, then, while, after, there. 
fore, finally, consequently, it follows, for this purpose, 
nez~, etc. 
Contrastive relations share the common feature 
of implying a contrast of some kind between the seg- 
ments they relate. The relations of this class repre- 
sent the negative counterpart of the two preceding 
classes, thus involving a negative component. As a 
consequence, this type can be further specified in 
two subtypes, one which defines those cases imply- 
ing the negation of a similarity and another which 
defines those cases implying the negation of an impli- 
cation. More precisely, a contrastive relation holds 
when 
a) p(x) can be inferred from the assertion of $1 and 
p(y) can be inferred from the assertion of $2 
(negation of the additive type). For example: 
14. John is good-looking ($I). Frank 
is ugly (s~). 
15. Cork county is characterized by 
luxuriant valleys and gorgeous coasts 
($I), whereas the territory of Kerry 
county is wilder and hilly ($2). 
b) p can be inferred from the assertion of Sl and q 
can be inferred from the assertion of $2, where p 
implies ~q (negation of the consequential type). 
For example: 
16. Torn is a lawyer ($I) but he is 
honest ($2). 
17. Although its port does not have 
the importance it had in the past (SI), 
Cork is still the second town of the re. 
public ($2). 
This type of relations covers 
Mann and Thompson's Antithesis, Concession, 
Otherwise and Contrast relations, Hobbs' Con- 
trast and Violated Expectation, Sanders et al.'s 
Contrastive Cause-Consequence, Contrastive 
Consequence-Cause, Contrastive Argument- 
Claim, Contrastive Clalm-Argument, Oppo- 
sition and Concession relations, as well as all the 
relations sharing a negative polarity value in the ap- 
proach of (Knott and Mellish, 1996). 
Typical markers of this class are but, while, on the 
other hand, on the contrary, however, although, nev- 
ertheless, in any case, in fact, actually, otherwise, 
etc. 
2 Experiment 1: The role of 
discourse markers in 
comprehension 
If connectives play a significant a role in directing 
the receiver toward the reconstruction of a discourse 
relation, their presence should result in a higher rate 
of correct recognition of relations, while their ab- 
sence should determine a significant worsening in the 
recognition ability; also, relations different from the 
original ones may be inferred more easily. 
2.1 Methodology and Data Collection 
In Experiment 1 subjects had to label the relation 
perceived between two textual segments, presented 
in two different versions, either with or without the 
original connective. 
The material for the experiment consisted of two 
sets of 72 pairs of discourse segments, embedded in 
a larger context. The segments were taken from a 
corpus of written texts, of various genres; all items 
were in Italian. In the "with connective" version, the 
segments had not been altered; in the "without con- 
nective" version, the original text was modified as 
little as possible. The segments had been chosen in 
order to form a representative set of the three classes 
of coherence relations (21 examples for the additive 
type, 27 for the consequential type, and 24 for the 
contraztive type; attribution of actual instances to 
types was made on the basis of the taxonomy in 
section 1), as well as to display a vast range of con- 
nectives for each type of relations. 
The subjects were ten undergraduate students. Sub- 
jects were instructed to spontaneously label the re- 
lation they perceived between the two segments. A 
half of the subjects had to read 36 examples with 
the connective and 36 without: the other half had to 
read the same examples, in inverted order. 
2.2 Results and Discussion 
The data were analyzed according to the following 
criteria. For each type of relation, we determined the 
number of cases where the relation between the seg- 
ments was correctly inferred, either with connective 
and without connective. A relation was considered 
to be correctly inferred when the spontaneous label 
chosen matched our taxonomy-based classification. 
Those cases where the relation was not correctly 
38 
Additive Type 
with conn. without conn. 
correct identification 72.6 64.3 
uncertain 1 ~.9 9.5 
confusions with 2.4 14.3 
contrastive 
confusions with 13.1 11.9 
consequential 
Consequential Type 
with conn. without conn. 
correct identification 88.9 60.2 
uncertain 2.8 3.7 
with 0.9 8.3 confusions 
contrastive 
confusions with 
additive 
7.4 27.8 
Contrastive Type 
with conn. without conn. 
correct identification 83.3 42.7 
uncertain 2.1 9.4 
confusions with 
additive 
confusions with 
consequential 
9.4 
5.2 
31.2 
16.7 
Table 1: Percentage of recognitions per type 
retrieved were further classified in uncertainty in- 
stances and confusion instances (i.e., when subjects 
attributed the relation to a different class). Table 1 
illustrates the data for each of the three classes of 
coherence relations. 
The degree of correctness in the answers is taken 
to be representative of the degree of comprehension 
of the relations. The data confirm our hypothesis 
that a connective facilitates the interpreters' ability 
to infer the relation intended by the message sender. 
For all types of relations, the absence of the con- 
nective corresponds to a reduction in the number of 
correct answers. However, this reduction displays 
distinct patterns according to the type of relation 
involved. The contrastive type shows the highest re- 
duction, while the additive type the lowest. The con- 
sequential type holds an intermediate position. Sim- 
ilarly, the different types of relations are not equally 
affected by the presence/absence of a connective: 
additive relations seem to be less comprehensible 
than contrastive and consequential relations; how- 
ever, they are those which are best comprehended 
when lexical signalling is missing. 
The difficulty with which a contrastive relation 
is inferred without a connective could be due to the 
fact that lexical marking is essential for the inference 
of the contrastive component of meaning. Accord- 
ing to our hypothesis, the contrastive type should be 
cognitively more complex than the other two, since it 
involves an additional negative component. If there 
is lack of marking, the negative or contrastive com- 
ponent of the relation is lost and the relation is thus 
interpreted as an additive or consequential relation, 
according to the underlying type, as it is shown by 
the redistribution into these other two classes. 
Lexical marking seems not to have a fundamen- 
tal role for guiding the inference of additive rela- 
tions: in fact, there is only a slight difference be- 
tween the number of correct answers in the condi- 
tion with connective and those in the condition with- 
out connective. This could be due to two different, 
non competing factors: first, it could be that ad- 
ditive connectives are not particularly efficient for 
guiding the inference of the relation because of their 
intrinsic ambiguity. Second, it could also be the 
case that interpreters tend to instantiate whenever 
possible a "stronger" implicational relation between 
two segments. Numerous studies (of., among others, 
Townsend and Bever, 1978; Trabasso and Sperry, 
1985; Trabasso and van den Broek, 1987; Garnham 
et al., 1996; Noordman and Vonk, 1997) suggest that 
the various types of relations differ not only along 
the dimension of cognitive complexity, but also along 
the dimension of cognitive relevance. According to 
• these studies, causal and temporal relations are cog- 
nitively more relevant since they promote the storage 
in memory of the connection between information. 
On the other hand, the ease with which an additive 
relation is inferred when there is no lexical mark- 
ing to signal it could be explained by the fact that 
a relation of this type is inferred by default, since 
it signals a simple and general continuation without 
ally other particular connotation. 
Consequential relations, while showing a reduc- 
tion in the number of correct answers from the con- 
dition with connective to the condition without con- 
nective, display a relative ease of comprehension. 
This is not plausibly explained by making refer- 
ence to the basic common knowledge shared by writ- 
ers and readers, since this should determine a good 
recognition of contrastive relations as well. It is more 
advantageous to hypothesise that the high degree of 
understanding of consequential relations is related to 
the well-known preference toward inferring an im- 
plicational relation between the segments (el. for 
example Black and Bern, 198!). Again, the fact 
that this class of relations is the best comprehended 
one whith lexical signalling is explainable in terms 
of semantic non-ambiguity of the connectives usually 
39 
employed for its expression. 
In sum, Experiment 1 supports the hypothesis 
that connectives have a facilitating effect for the 
inference of the relations intended by the message 
sender. The fact that not all types of relations are 
equally facilitated by a connective has been inter- 
preted as the result of three different phenomena: 
a) semantic ambiguity of connectives for the additive 
class vs. non-ambiguity of connectives for the conse- 
quential and contrastive classes; b) higher cognitive 
complexity of the contrastive type of relations and 
hence necessity of connectives for the understanding 
of the contrastive meaning; c) different cognitive rel- 
evance of the different classes of relations. 
3 Experiment 2: The role of 
discourse markers in production 
The aim of our second experiment consisted in ver- 
ifying whether there is any significant difference be- 
tween spoken and written language, in terms of the 
kind of relations employed and of lexical marking of 
the relations. We decided to compare the spoken 
and written narratives produced by subjects about 
a common topic. Our original hypothesis was that 
spoken language would display a lower proportion 
of cognitively more complex relations as well as an 
increase in the global marking of the relations. The 
first expectation was due to the hypothesis that spo- 
ken language, being constrained by the limitations 
imposed by short-term memory, would avoid the 
cognitively more complex relations and, at the same 
time, would contain a higher number of connectives 
as a trace or footsteps of the cognitive processes un- 
derlying the production process. 
3.1 Methodology and Data Collection 
The stimulus employed for this experiment consisted 
in a humorous story depicted in a set of eleven car- 
toons, put in order. Pictorial material was consid- 
ered to be appropriate for the experiment in that it 
enables the analyst to have a comparable set of nar- 
ratives based on the same subject; in addition, the 
pictorial form provides a neutral input with regard 
to the target form of expression (spoken or writ- 
ten), thus preventing from a priming effect. The 
subjects were 19 undergraduate students, who were 
instructed to look at the cartoons and tell the story 
they presented (the data for subject 9 had been later 
excluded from analysis). Once the spoken narra- 
tive was concluded, they were asked to put the story 
in written form. Spoken narratives were taped and 
transcribed according to the standard Italian orthog- 
raphy. 
length 
SPOKEN 
n. of conn. I conn/claus 
10.6 \[ 1:1.6 131w. 21c. 
Table 2: Length of narratives and percentage of con- 
nectives for spoken language; w = words, c = clauses 
WRITTEN 
length I n. ofconn. I conn/claus 
95w. 16c. 7.6 1:2.5 
Table 3: Length of narratives and percentage of con- 
nectives for written language 
In order to compare the two versions of the narra- 
tives, each pair of narratives underwent three levels 
of analysis. First, the total number of connectives 
was measured, as well as the percentage of connec- 
tives in relation to the total number of words and the 
ratio connectives:clauses. Second, after translating 
the narratives into a propositional form, we labelled 
the individual relation holding between a proposi- 
tion and the preceding one and we determined the 
relative percentage of every class of relations for both 
versions, spoken and written. Finally, for each class 
of relations we measured the proportion of relations 
which were signalled by a connective. 
3.2 ResuRs and Discussion 
3.2.1 Length of narratives and percentage 
of connectives 
Tables 2 and 3 illustrate, for each pair of narratives, 
the mean values for length, the total number of con- 
nectives, the percentage of connectives over the total 
number of words and the connectives:clauses ratio. 
The figures show a steady tendency toward a de- 
crease in the number of connectives from the spoken 
to the written version of the narratives (M = 10,6% 
in the spoken version, 7,6% in the written version). 
3.2.2 Types of relations employed in the 
two versions 
Table 4 shows a comparison of the relations em- 
ployed in the spoken and in the written versions 
of the narratives (where A means additive type, 
CS consequential, and CTcontrastive, respectively). 
The data show no significant difference between the 
sPOKEN WRITTEN 
A Cg \] CT A \] CS \]CT 
40.4 ,t9.6 i0.0 43.4 46.7 9.9 
Table 4: Types of relations employed in the two ver- 
sions (mean percentage values). 
40 
\[ SPOKEN I WRITTEN 
l 48.4 37.3 
Table 5: Percentage of lexically signalled relations 
(mean values) 
spoken and written versions: in both cases most of 
the relations belong to the consequential and addi- 
tive types, with a relatively low percentage of con- 
trastive relations. There is a straightforward rela- 
tion between the slight preponderance of the con- 
sequential type and the nature of the task: since 
the narratives describe a story, it is obvious that the 
consequential type of relation would be the prevail- 
ing one. Another possibility, which is not in contrast 
with the preceding one, is that consequential type is 
preferred because it is cognitively "stronger" than 
the additive (cf. Experiment i). Nevertheless, it is 
safe to assume that consequential and additive rela- 
tions represent to a large extent alternative choices 
for the organization of the narrative content, as it is 
shown by the high degree of individual variation. 
Regarding contrastive relations, it can be noted 
that they are generally little employed, both in spo- 
ken and in written language. As before, this genera\[ 
phenomenon could be explained by reference to the 
nature of the task; however, an alternative explana- 
tion could be in terms of avoidance of cognitively 
complex relations discussed earlier. Again, there is 
no difference in the percentage of use between spo- 
ken and written versions of the narratives. 
3.2.3 Lexieal realizations 
If the data concerning the use of relations do not 
exhibit a significant variation explainable in terms of 
an influence of the spoken vs. written modality, the 
data regarding the lexical marking of the relations 
are highly indicative of some constraints imposed by 
the means of expression. Table 5 shows tile global 
percentage of lexically signalled relations in the two 
versions of the narratives. 
The figures suggest a uniform tendency toward 
marking the relations in the spoken versions, which 
drastically drops in the written form. This frame- 
work is consistent with our original hypothesis, i.e. 
that the spoken form would exhibit a higher num- 
ber of connectives in that they represent a footstep 
of the cognitive processes underlying production. 
At a closer inspection, however, it turns out that 
the reduction of lexical marking in writing displays 
again distinct patterns according to the type of re- 
lations involved. Table 6 illustrates for each class of 
relations the proportion of relations signalled by a 
connective. 
si°KE r 'v  ITTi  A CS CT A CS CT 
21.6 59.7 95.3 24.8 43.4 91.7 
Table 6: Percentage of relations signalled by a con- 
nective for the two versions (mean values) 
As it can be seen, the contrastive type holds the 
highest degree of marking (over 90% in the two ver- 
sions); the consequential type of relations shows a 
relatively high degree of marking (around 60% in 
speaking, around 40% in writing). On the other 
hand, the additive type has a very low rate of lexi- 
cal signalling (around 20%). In addition, the figures 
show that reduction in the degree of lexical signalling 
significatively concerns the consequential type only 
(- 16.3%), while the contr~tive type is only slightly 
affected (-3.6%); more importantly, reduction does 
not concern the additive type, which shows an oppo- 
site tendency toward an increase in the global per- 
centage of lexical marking (+3.2%). 
The fact that a contrastive relation is almost al- 
ways marked by a connective, either in speaking and 
in writing, indicates that connectives are obligatory 
for this class. This is again in accordance with the 
hypothesis of a higher cognitive complexity for this 
kind of relations. In production, thus, higher cog- 
nitive complexity imposes a constraint in the form 
of an obligation to lexically signal the relation (this 
also indicates that graphic and punctuation markers 
are felt as inadequate for a correct retrieval of the 
relation). 
The relatively low degree of lexical marking of 
the additive type in speaking indicates a tendency 
against the marking of the relation which is inverted 
in writing. However, the data for writing (here not 
presented in full) show a higher individual variation 
than the one in speaking and as a result they sug- 
gest a less consistent tendency to mark the relation 
as opposed to the steady one for speaking. 
For what concerns the consequential type, writ- 
ing and speaking show a similar tendency to consis- 
tently and steadily signal the relation, but, again, 
the written language highlights a higher individual 
variation, and the general percentage of marking is 
significantly lower than in the oral versions. For 
the additive and consequential types, thus, the data 
show an influence of the means of expression in terms 
of an increased degree of lexical marking for the spo- 
ken versions which decreases in the written versions. 
This latter phenomenon could be due to the fact that 
writing has graphic and punctuation marks available 
in order to signal the relation. 
41 
In sum, with reference to our original questions, 
i.e. a) whether the means of expression (oral vs. 
written) constrains the type of relations used in the 
narratives; b) whether any difference could be re- 
lated to the use, in spoken language, of cognitively 
less complex relations; c) whether spoken language 
manifests a tendency toward marking the cognitively 
more complex relations; and d) whether spoken tan- 
guage shows a significantly higher use of connectives, 
as a trace of the cognitive processes involved in pro- 
duction, the data from our second experiment sug- 
gest the following conclusions. 
a) Discourse relations do not depend on the 
modality of expression, since both spoken and writ- 
ten narratives show a basically identical use of the 
three classes; this directly rules out question b). 
With regard to question c), this is contradicted by 
the data, which show that lexical marking is almost 
obligatory for contrastive relations both in spoken 
and in written language. Finally, the hypothesis un- 
derlying question d) is strongly strengthened by the 
data relative to the degree of signalling of the dif- 
ferent types of relations. The spoken versions show 
a large use of connectives, which is globally much 
higher than it is for the written versions. As regards 
a comparison among the different types, the almost 
obligatory marking of contrastive relations, both in 
speaking and in writing, represents an unexpected 
finding, which is nevertheless consistent with tile hy- 
pothesis of a higher cognitive complexity of the con- 
trastive type. A further phenomenon is represented 
by the low degree of marking of additive relations 
compared to consequential relations for which we do 
not possess at present a convincing explanation. 
4 Conclusions 
The Experiments shown in the previous sections sug- 
gest that lexical marking of discourse relations is not 
entirely optional but is at least partially constrained 
by the type of relation signalled and the means of 
expression. Thus, contrastive relations obligatorily 
need a connective both in comprehension and in pro- 
duction, while lexical marking does not appear to 
be as necessary for additive and consequential rela- 
tions. Although the data do not allow to conclude 
that there are discourse relations that are never lex- 
ically signalled, additive relations appear to be only 
sparsely marked; in addition, lexical marking does 
not significatively improve the comprehension for 
this class of relations. The means of expressions 
constrains lexical marking in that spoken discourse 
requires a higher number of cue phrases than it is 
necessary for written discourse. However, there is no 
evidence whatsoever of a difference between speak- 
ing and writing in the marking of relations according 
to type. 

References 
\[i\] Black, J. and H. Bern. 1981. "Causal coherence 
and memory for events in narratives." Journal of 
Verbal Learning and Verbal Behavior 20: 267-275. 
\[2\] Garnham, A., Traxler, M., Oakhill, J. and M.A. 
Gernsbacher. 1996. "The locus of implicit causal- 
ity effects in comprehension." Journal of Memory 
and Language 35: 517-543. 
\[3\] Hobbs, J. R. 1985. "On the coherence and struc- 
ture of discourse". Technical Report No. CSLI-85- 
37, Stanford, CA: Center for the Study of Lan- 
guage and Information, October 1985. 
\[4\] Hobbs, J.R. 1990. Literature and Cognition. CSLI 
Lecture Notes. Stanford, CA: CSLI. 
\[5\] Knott, A. and C. Mellish. 1996. "A feature-based 
account of the relations signalled by sentence and 
clause connectives." Language and Speech 39: 143- 
183. 
\[6\] Mann, W. C. and S. A. Thompson. 1986. "Rela- 
tional propositions in discourse". Discourse Pro- 
cesses 9: 57-90. 
\[7\] Mann, W. C. and S. A. Thompson. 1988. "Rhetor- 
ical Structure Theory: Toward a functional theory 
of text organization." Text 8: 243-281. 
\[8\] Noordman, L.G.M. and W. Vonk. 1997. "The dif- 
ferent functions of a conjunction in constructing a 
representation of the discourse." In J. Costermans, 
M. Fayol (Eds.), Processing \[nterclausal Relation- 
ships. Mahwah. NJ: Erlbaum, 75-93. 
\[9\] Sanders, T.J.M., Spooren, W.P.M. and L. G.M. 
Noordman. 1993. "Coherence relations in a theory 
of discourse representation." Cognitive Linguistics 
4: 93-133. 
\[10\] Townsend, D.3. and T.G. Bever. 1978. "Inter- 
clause relations and clausal processing." Journal 
off Verbal Learning and verbal Behavior 17: 509- 
521. 
\[11\] Trabasso, T. and L.L. Sperry. 1985. "Causal re- 
latedness and importance of story events." Jour- 
nal of Memory and Language 24: 595-611. 
\[12\] Trabasso, T. and P. van den Brock. 1985. 
"Causal thinking and representation of narrative 
events." Journal of Memory and Language 24: 
612-630. 
\[13\] van Dijk, T. A. 1977. Text and Context. London: 
Longman. 
