Planning units and syntax in sentence production - Science Direct

Cognition, @Elsevier

6 (1978) 35-53 Sequoia S.A., Lausanne

Planning

- Printed

in the Netherlands

units and syntax

in sentence

MARILYN

FORD*

VIRGINIA

M. HOLMES

University

production

of Melbourne

Abstract The study was conducted to determine, first, whether it is the deep or the surface clause that is more important as a speech planning unit, and second, whether syntactic decisions are made during sentence production. Subjects, while talking, heard tones to which they had to respond by pressing a button; reaction times to these tones were taken as an index of processing load during production. It was found that there were increased R Ts at the ends compared with the beginnings of deep structure clauses. No difference was found between RTs at the beginnings and ends of surface clauses not corresponding to a deep clause. The results were interpreted as showing that deep clauses are major planning units and that some planning for clauses occurs at the end of the preceding clause. Differences were found between RTs during clauses of different syntactic structure. These results were interpreted as indicating that syntax influences production and were discussed in relation to previous studies of pausing and speech disruption.

In order to produce an utterance which has coherent semantic organization and appropriate syntactic structure, a speaker must plan at least part of the utterance in advance. A central issue in the study of sentence production has been whether or not speakers plan in units that have some consistent basis. If they do, it seems likely that the unit is larger than the single word. Boomer (1965) found that hesitation pauses in spontaneous speech occurred towards the beginning of phonemic clauses. On the assumption that pauses reflect sentence planning activity, Boomer argued that speakers plan in phonemic clauses. Since phonemic clauses are usually surface structure clauses, these *Requests for reprints should be addressed Melbourne, Parkville, Victoria, Australia 3052.

to M. Ford,

Department

of Psychology,

University

of

36

Marilyn Ford and Virginia M. Holmes

results could also be interpreted as implicating the surface clause as a planning unit. This interpretation would seem to be supported by Hawkins (197 1), who found a much higher proportion of hesitation pauses at surface clause boundaries than at positions within clauses. In fact, the general opinion at the moment seems to be that the surface structure clause is probably the pri1974; Bever, mary speech planning unit (e.g., Fodor, Bever and Garrett, Carroll and Hurtig, 1976). The results of previous studies are, however, open to question. They do not preclude the possibility that speakers plan in more basic units such as simple propositions, which, in speech, correspond to deep structure clauses. It is possible that the deep structure clause is the primary speech planning unit and that the apparent importance of the surface clause has arisen because deep structure and surface structure boundaries often coincide. For example, the surface structure clause John is walking contains only one proposition or deep structure sentoid, and thus can also be considered as a deep structure clause. But the surface clause, John prefers to walk consists of two deep propositional units John prefers it and John walk which are realized in surface form by the deep structure clauses John prefers and to walk. Thus, in John prefers to walk the surface and deep structure clause boundaries do not coincide. It is impossible, from previous studies, to say whether it is the deep or the surface clause that is the more important unit. Because it is vital to the development of a model of sentence production to know the basic unit in which speech is planned, the present study aimed to see which of the two types of clauses is the major planning unit. Another important issue is whether decisions about syntax have to be made during sentence production. Goldman-Eisler (1968) has argued that general planning for content and syntactic structure takes place before utterances are produced, but that once a word is uttered, all further decisions involve lexical choice. She has proposed that selection of the syntactic structure occurs automatically, that words are merely slotted into an “existing structure” formed on the basis of well-learned routines. Her evidence for this view is not very convincing (cf., Boomer, 1970). Moreover, recent evidence has indicated that some syntactic operations do require planning. Rochester and Gill (1973) found that sentences .with different clause structure resulted in different amounts of disruption during their production. Specifically, complement sentences such as The fact that the woman was aggressive threatened the professors contained more filled pauses, corrections and other disruptions at the clause boundaries than superficially similar relative clause sentences such as The book which was written by Milleft was lauded by all. Results obtained by Goldman-Eisler (1972), showing that the amount of silent pausing differs before clauses of different syntactic types, could also be seen as suggesting that syntactic operations are involved in speaking. A second aim of

Planning Units and Syntax in Sentence Production

37

the present study was to seek further evidence for the role of syntactic decisions in sentence production. Clauses of the four major syntactic types were studied. It was not hypothesized that the more transformations needed to derive a certain structure the more difficult it would be to produce. Rather, it was simply hoped to see if clauses of different structure differ in production difficulty, thereby indicating that speakers make syntactic decisions of some sort. Most previous studies onsentence production have analyzed the occurrence of pauses or disruptions in spontaneous speech, assuming their location and frequency to be a valid index of where planning takes place and of how difficult it is. In fact, Goldman-Eisler (1968) has claimed that planning can only occur during pauses. However, it is possible that speakers can plan and talk at the same time. If this is true, then the study of pauses and disruptions alone is limited, since planning cannot be examined while words are actually being uttered. To overcome this problem, in the present study we used a modification of a technique used by Valian (197 1) which was based on the “click” reaction time task of Abrams and Bever (1969) and Holmes and Forster (1970). While they were talking, Valian’s subjects heard high- and low-pitched tones to which they had to make a motor response. The reaction times were presumed to measure the amount of spare processing capacity available at the time of the tone’s occurrence and thus to measure the difficulty of speech encoding at that point (cf., Kahneman, 1973). Valian compared reaction times at the beginnings and ends of surface and deep structure clauses in an attempt to decide which was the critical planning unit. However, her results did not allow an unequivocal interpretation to be made. Reaction times decreased significantly from the beginning to the end of clauses which were both surface and deep units, but this pattern did not hold true for surface clauses containing more than one deep structure clause, a result which would have been necessary to establish the surface clause as the more important unit. Similarly, the significance of the deep structure clause was not demonstrated either, because reaction times did not vary within deep structure clauses that did not correspond to surface structure clauses. It seems likely that the lack of any clear trends in Valian’s data results from the generally very high variance in the reaction times. Perhaps the most obvious possible cause for this was the extreme difficulty of the task, a fact which Valian herself conceded. Subjects had to discriminate between two different tones occurring very frequently, as often as once a second, and make an accurate motor response while they were telling stories to a friend. In the present experiment we felt that more reliable results would be obtained using a simple reaction time task with the tones occurring at longer intervals than those used by Valian. To further reduce error variance our subjects talked to the same

38


person rather than to a friend. It was hoped that an examination of performalice on this task would provide some insight into the nature of sentence production.

Method Design and Procedure

The subjects, who were unaware that the experiment was concerned with sentence production, were each interviewed individually by the senior author in two half-hour sessions. In one session the subjects heard and responded to tones while talking; in the other session tones were not presented, as a check for the possibility of disruptive effects of tones in the tone condition. Half of the subjects were interviewed in the tone condition first, and half were interviewed in the nontone condition first. In each session subjects spoke on five topics, the first of which was a practice topic. The eight test topics were The Role of Men and Women in Society, Attitudes to University Life, Old People, Childhood, Migrants, Schools You have Attended, Prevention and Punishment of Crime and Family Life. Eight orderings of the topics were used. At the introduction of each new topic subjects were asked three broad questions about it which were then repeated. Subjects talked for about five minutes on each topic. For the tone condition subjects were instructed to keep their right index finger on a response button and to press it as quickly as possible whenever they heard a tone. The subjects wore an earphone/microphone set through which they heard the tones, their own speech and that of the experimenter. Tones, which were 100 milliseconds in duration and 1000 Hz in frequency, were generated randomly by a PDP-1 1 computer at intervals of 2.0, 2.5, 3.5, 4.0 and 5.0 seconds. Reaction times to the tones were measured by the computer in milliseconds, and the tones and speech were tape-recorded. Data A naI_vsis

The subjects’ speech was transcribed verbatim by one of the experimenters. To locate the tones within the speech, the experimenter listened to the tapes at a reduced speed while following the speech on the transcripts. Pen recordings of the tapes were used to determine whether any tone near the beginning or end of a word actually occurred during the word or between words. The speech was then segmented into sentences, which were further segmented into surface and deep structure clauses. Each unit of speech which contained either an explicit or an implied verb was classified as a deep clause. Prenominal adjectives were not regarded as deep clauses because some discontent has been


39

expressed about deriving these from underlying sentences (cf., Lazarus, 1973). The speech in each clause was coded both for completeness, and for the number and position of meaningful words, filled pauses, repetitions, word choice mistakes, tongue slips, intruding incoherent sounds, and redundant words such as well and you know. The word and was considered as redundant when the speech following it was not syntactically dependent on the speech preceding the and as, for example, in the utterance There’s only room for one snob suburb and we weren’t in it. The words but, because, although, so and then were considered redundant in cases where, if they were omitted, the utterances preceding and following them were still meaningful. The word but, for example, was considered redundant in the utterance Some societal alterations could cure crime but I think the best way to cure it is to cure sick individuals. After the speech in the clauses had been coded the reaction times were marked on the transcripts and coding sheets. Reaction times in or before an incomplete clause were not included in the analyses. For each data analysis, the mean of the RTs of a given subject was calculated, and, in order to minimize the influence of any extremely long or short RTs, any score which was more than two standard deviations away from the mean was set at that cutoff value. Five per cent of the scores were adjusted in this way. For each subject, the means of the RTs from relevant speech samples were determined for the different classifications. Repeated measures analyses of variance with planned orthogonal contrasts were performed on these data (Kirk, 1968, pp. 81-82). Statistical decisions were based on a Type 1 error rate of (Y= 0.05. It should be noted that the min F’ statistic (Clark, 1973) is not relevant to the present experiment. Since each subject produced a different number and a completely different set of ‘items’, any significant result obtained could not be due to any particular ‘item’ or ‘items’. In fact, the calculation of min F’ would be impossible. For most analyses there were enough RTs to obtain reliable means for each subject. In three cases only was it necessary to estimate missing data for subjects by using Yates’ (1933) procedure. In carrying out the analyses when estimations were made, the degrees of freedom for the error sums of squares were appropriately reduced (Yates, 1933; Kirk, 1968, pp. 146-147) and corrections for bias of the treatment sums of squares were made (Yates, 1933; Anderson, 1946). Also, adjustments to the number of effective replications were made in performing the planned contrasts (Taylor, 1948). Footnotes in the tables of results show when Yates’ (1933) procedure was used. While the segmentation of speech into different clause types is relatively objective, it could be argued that segmenting spontaneous speech into sentences is difficult. Therefore, an independent judge was given transcripts of speech from four subjects, each talking on a different topic in the tone con-

40


dition, and was asked to segment the speech into sentences by applying criteria used by the experimenter. The judge and the experimenter agreed on 94% of the sentence boundaries. It might also be thought that one possible difficulty with the ‘click’ technique could be that the number of tones occurring during as opposed to between words might differ for different conditions and that significant RT differences could thus be due simply to whether or not subjects were vocalizing when a tone occurred. However, analyses were performed which ruled out this possibility. RTs during and between vocalizations were compared for each analysis of the study. The differences obtained were not consistent and in no analysis did they approach significance. Subjects

The subjects were 10 paid volunteers from the general student population at the University of Melbourne. They were all native speakers of English. The data for one subject were rejected because for over 15% of the tones he either forgot to respond or took longer than 1.4 seconds. The data for one other subject were rejected because his speech was indistinct.

Results Disruptions

It was first necessary to establish that requiring the subjects to listen for tones and respond to them did not prove disruptive to their speech. For each subject the number of meaningful words and speech disruptions was totalled as a measure of speech output, and the percentage of output consisting of different disruptions was calculated for the tone and nontone conditions. The group means are shown in Table 1. The main effect of disruption type was significant, F(6,42) = 41.68. Tukey’s HSD test for making post hoc pairwise comparisons among means (Kirk, 1968, pp. 88-90) showed that there was more speech consisting of redundant words than of any other types of disruption, and more filled pauses than tongue slips. The crucial finding was that the percentage of disrupted speech in the tone and nontone conditions did not differ significantly, F( 1,7) = 1 .lO. The interaction between speech condition and disruption type was also not significant, F(6,42) = 1.33. To see if there might have been more silent pausing in the tone than the nontone condition, the mean number of speech elements (words and speech disruptions) per minute was calculated for each subject by sampling two minutes of speech from each topic. The mean number of elements per minute in the nontone condition was 160.9, while that in the tone condition was


Table 1.

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Mean percentage of speech consisting of different types of disruption for tone and nontone conditions Disruption

type

Speech

condition

Tone

Nontone

Filled pause Redundant word Repetition Word choice mistake Sentence incompletion Tongue slip Intruding sound

4.0 10.3 1.4 0.6 1.8 0.2 0.4

3.4 9.3 1.6 0.8 1.7 0.3 0.6

Total

18.7

17.7

162.1. The lack of any significant difference between these values (F < 1) provides further evidence that hearing and responding to tones had no detectable effect on the subjects’ speech. Deep

vs. Surface

Structure

Clauses as Planning

Units

By studying the production of clauses which are both deep and surface structure clauses, such as those in (A) of Table 2, it is possible to see if clauses are important planning units, though it is not possible to see whether it is the deep or the surface clause that is of primary importance. To answer this question, a different set of clauses must be examined. It is vital to study, as separate units, deep structure clauses which do not correspond to surface clauses, as shown in (B) of Table 2, and the surface clauses containing such units, as shown in (C). Thus, processing load at the beginnings and ends of these three types of clauses was studied. The beginnings and ends were the first and last half of clauses respectively, the division being made on the basis of the number of meaningful words in a clause. For clauses which were both deep and surface clauses, RTs were studied at the beginnings and ends of the first clause in a sentence and at the beginnings of the second clause. RTs at the ends of second clauses were not examined because such segments do not form a homogeneous group - some are followed by another clause while others are not. The analysis permitted RTs in three consecutive segments, each of which was relatively homogeneous, to be studied. The mean data over the eight subjects are shown in Table 3. RTs during the ends of the clauses were significantly longer than those at the beginnings, F( 1,14) = 5.64. There tended to be longer RTs at the beginning

42


Table 2.

Examples of sentences analyzed into clauses Sentences If capital punishment were brought in the murder rate would go down. I began working a lot harder when I finally decided to come to Uni. _ Clause analysis (A)

Clauses which are both cleep and surface structure If capital punishment were brought in 1. the murder rate would go down 2.

(B)

Deep structure 1. 2.

(C)

I began working

clauses which do not correspond 3. a lot harder 4.

Surface structure 1. 2.

clauses which

contain

clauses

to surface clauses when I finally decided to come to Uni

more than one deep clause

I began working a lot harder when I finally decided to come to Uni

-

Table 3.

Mean RTs (msec) as a function

of clause segment in clauses which are deep

and surface clausesa Clause segment Beginning

of first clause

Beginning

of second

aThe mean number

431 (9) 470 (10)

End of first clause clause of items per cell is shown

399 (12) in parentheses.

of the first than the second clauses, but the difference was not significant, F(1,14) = 1.36. The result showing that processing load increases towards the end of clauses which are both deep and surface clauses provides some evidence that clauses may be planning units and that planning may occur during the end of the previous clause. The two critical sets of clauses were examined next, to see which is more important: the deep or the surface clause. To analyze deep structure clauses not corresponding to surface clauses, the surface units containing these clauses were classified as being either (a) the first or only surface clause in a sentence or (b) a subsequent surface clause. Mean RTs at the beginnings and ends of the first deep clauses and the beginnings of the second deep clauses were studied. As the ends of the second clauses do not

43


form a homogeneous group these were not considered. For the analysis of surface clauses containing more than one deep unit, the presence of the deep clauses was ignored and RTs were examined in segments analogous to those studied in clauses that were both deep and surface clauses. Examples of subjects’ speech and the classification of tone locations in regard to the analyses are shown in Appendix A. In Table 4 the mean data for the critical sets of clauses are presented. For deep clauses, RTs were significantly longer at the ends of clauses than in the preceding and following beginnings of clauses, F (1,14) = 5.84. Neither the main effect of surface clause position nor the interaction between this factor and deep clause segment was significant, with F (1,7) = 2.95 and F (2,12) = 1.06 respectively. Thus, the same pattern of RTs during deep clauses exists regardless of the position of the surface clause in the sentence. Moreover, these results are the same as those found for clauses which are both deep and surface clauses. In contrast, no such pattern was found for the surface clauses which did not correspond to one deep unit: RTs at the ends of the clauses were not significantly different from those at the beginnings, F < 1. A further finding was that, overall, there was a tendency for RTs to be longer at the beginning of the first than the second clauses, though the result for neither the deep nor the surface clause analysis was significant, with F < 1 and F (1 ,13) = 1.11 respectively. The fact that the results obtained for clauses that were both deep and surface units were also found for the critical set of deep clauses, but not for the surface clause set, suggests that clauses which are deep units are basic units of planning. It has been assumed so far that the increase in RT at the ends of deep clauses is a function of speakers planning what to say in the next deep clause. An alternative view is that the increased processing load results from the Table 4

Mean RTs (msec) as a function of clause segment in the critical set of deep and surface claUsesa Clause segment

Beginning

Deep clauses

of first clause

End of first clause Beginning

of second

clause

Overall

Surface clauses

406 (8)

415

430c (4)

477 (6)

463

429

(5)

417 (5)

401

413

(9)

In fist or only surface clause

In subsequent surface clauses

423

(7)

448

(8)

384b (3)

%re mean number of items per cell is shown in parentheses. bin this cell the data for two subjects were estimated. ‘In this cell the datum for one subject was estimated.

44


speakers monitoring what they have just said. If this explanation is correct, RTs would still be expected to increase in deep clauses that are at the end of a sentence. However, if the increased RTs are largely due to planning for the next deep clause, then it is not so obvious that a variation in RTs would be expected in the last clause of a sentence. It is clear from the work of GoldmanEisler (1972), for example, that sentences are distinct units in speech and are, in the majority of cases, preceded by a pause. Thus, it seems unlikely that much planning of a completely new sentence would take place while the previous sentence was still being uttered. To see, then, whether increases in processing load at the end of deep clauses are due to monitoring or planning, RTs were examined for the two types of deep clause at the end of a sentence. The mean data are presented in Table 5. Neither the main effect of clause segment nor its interaction with clause type was significant, with both Fs < 1. The main effect of clause type was also not significant, F (1,7) = 1.6 1. These results lend support to the idea that the increased processing load is caused by planning for the next deep clause, rather than by monitoring earlier output. The results so far presented suggest that the deep clauses in a sentence are planned and produced successively. However, it is very possible that before each surface clause containing more than one deep unit, there is some planning and integration of all the deep clauses it contains. If the latter is true, then it might be expected that RTs would be longer before surface clauses containing more than one deep unit compared with surface clauses containing only one. RTs were considered before surface clauses at the beginning of a sentence, and during the ends of clauses preceding clauses later in the sentence. As Table 6 indicates, the mean RTs did not differ consistently as a function of the number of deep units contained by the surface clause. For both initial and subsequent surface clauses, the differences were not significant, with both Fs < 1. It appears that before a surface clause there is little, if any, planning and integration of all the deep clauses it contains, and thus that it is essentially only the first deep clause that is planned prior to the beginning of a surface clause. We have no evidence, then, to reject the hypothesis that sentence production does proceed basically by each deep clause being successively planned and uttered. Syntax and Production

Difficulty

The possibility that processing load might differ for clauses of different syntactic types was investigated to see whether speakers make decisions about syntax. Examples of the four types of deep clause considered are shown in italics in sentences (A) - (D) in Table 7. Since the results presented so far suggest that some planning occurs during the end of deep clauses, RTs


Table 5.

45

Mean RTs (msec) as a function of clause segment in final deep clauses of a sen tencea Clause segment

Clauses which are both deep and surface clauses

Deep structure clauses not corresponding to surface clauses

Overall

Beginning End

426 (12) 429 (16)

385 (5)

405 415

401(10)

&The mean number of items per cell is shown in parentheses.

Table 6.

Mean RTs (msec) before surface clauses as a function of number of deep unit? Segment

Before surface Before surface

initial clauses subsequent clauses

Number of deep units in surface clause One

More than one

417 (41)

435 (11)

453 (14)

429 (5)

aThe mean number of items per cell is shown in parentheses.

Table 7.

Examples of clause types (A)

Complements Her father thought that she should go to Uni. I liked swimming in rivers when I was a child.

(B)

Adverbials I went to a country school when I was in England.

(0

Right-branching relatives It had super footbrakes which you pressed on to stop it. They’ve got a wealth of experience to look back on.

(D)

Nonembedded clauses My brother came to Uni but my sister didn’t. As I was lonely I didn’t like Uni when I fist came.

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were examined at the end of clauses preceding the four types. To see if there are differences in difficulty in the output phase when producing clauses of different structure, RTs during the beginning of the clauses were also exam ined. Allinstancesof the four types of clauses were included if they followed a completed clause. In Table 8 the mean data are shown. There was no significant clause type effect before the clauses, F < 1. However, at the beginning of the clauses the effect was significant, F (3,2 1) = 7.25. Post hoc orthogonal comparisons using Scheffes (1953) method showed that RTs during nonembedded clauses were significantly shorter than those during any other types of clauses, with F (1,2 1) = 10.0 1, and that RTs during right-branching relatives were significantly longer than those during complements and adverbials, F ( 1,2 1) = 11.3 1. The difference between complements and adverbials was not significant, F< 1. Table 8.

Mean RTs (msec) before and at the beginning of clauses as a function of clause type” Clause type ---

End of preceding

Complements Adverbials Relatives Nonembedded

447 448 432 440

aThe mean number

clause

413 427 483 385

(14) (6) (7) (9)

of items per cell is shown

Beginning

of clause -

(16) (8) (5) (6)

in parentheses.

Discussion The conclusion that the deep structure clause is the major unit of speech planning is opposed to the generally accepted view that the surface or phonemic clause is primary. The contrast between the suggestions from previous research (e.g., Boomer, 1965; Hawkins, 1971) and the present conclusion can be explained by the fact that the role of deep clauses has previously been ignored in production studies. The present findings suggest that the significant results of these earlier studies were caused by the fact that the critical speech constituents were deep clauses, and not, as has previously been assumed, by the fact that they were surface clauses. From the results of the present research it is obvious that in studies investigating planning units it is essential to distinguish the three possible classes of deep and surface clauses. While these three clause sets were considered in


47

Valian’s (197 1) study, her data, as already stated, could not justifiably be interpreted as showing whether deep or surface clauses are more important. It is interesting though, that Valian found RTs to be significantly longer at the beginning than the end of clauses which were deep and surface clauses. It is possible that this result was obtained because the serial position of clauses was not taken into account. Thus, for example, the first and last clauses of sentences would have been classified together. The present results indicate that such a procedure would have masked any real differences between the beginnings and ends of clauses. Also, there was a tendency in the present study for RTs to be longer at the beginning of the first than the second clause, although the differences were not significant. If there is any decrease in RTs throughout a sentence, then it is vital, in “click” studies, that only those clauses which occur in the same serial position be classed together. Fodor et al. (1974) have been the only theorists to argue that the abstract deep structure of sentences has “psychological reality” for the speaker, even though they have suggested that the surface clause is the basic speech planning unit. They hypothesize that the abstract deep structure is one processing level in the translation of ideas into sentences. The results of the present study cannot show that representations of standard abstract deep structures are constructed by speakers. However, the results do show that speakers must form representations of sentences in which propositions corresponding to deep clauses are encoded separately. The representation of the propositions within a sentence may eventually be shown to be that of a standard abstract deep structure. If this is so, however, it would appear from the present study that abstract deep sentoids would be even more important than Fodor et al. suggest. They maintain that the deep structure representation of a sentence “guides” its construction in such a way that when a surface clause contains a number of deep clauses, the sentence producer integrates the deep sentoids and translates these into a surface clause form. The results of the present study suggest that if sentence construction is “guided” by a deep structure representation, each abstract deep sentoid is independently translated into a surface form as a sentence is being produced. It is clear that the representation of a sentence is constructed with the progressive addition of new propositions corresponding to deep clauses. It is instructive to consider the present results in relation to views put forward about the perceptual segmentation of speech. Although there have been studies indicating that some kind of clause is the major unit of speech perception (for a review see Fodor et al., 1974), it has recently been suggested by Tanenhaus and Carroll (1975) that clauses may vary in the degree to which they can act as perceptual units. They have suggested that clauses that are more complete, that is, clauses where the relations between actor, action and

48


object are more clearly specified, are better perceptual units than are more degraded clauses. Thus, for example, on their view the surface structure clause that Jim refused the offer would be a better perceptual unit than the deep structure clause Jim’s refusing the offer. A number of degraded clauses may need to be processed together to form a perceptual unit. Tanenhaus and Carroll have reported that they have found some support for their views. The results of the present study, however, show that in speech production very degraded clauses are just as important as very complete clauses, the results for deep clauses being the same regardless of whether or not they corresponded to a surface clause and thus regardless of whether or not they were complete or degraded. It seems, then, that the basic units of speech production and speech perception might differ. Perception requires listeners to recover propositions that someone else has expressed. Thus, when propositions have been expressed in the form of very degraded clauses, the listener may need to process several successive clauses before being able to recover much meaning. Production, however, requires speakers to produce propositions that they themselves have created. Regardless of the form of the clause in which a speaker chooses to express a proposition, that proposition must have been planned. In production, then, a clause corresponding to a deep propositional unit may be a unit of planning no matter how completely it expresses the proposition. One important point to note is that if Tanenhaus and Carroll (1975) are correct, then the basic perceptual unit does not correspond to a specific syntactic unit. Since it corresponds to a stretch of speech where the meaning expressed can be recovered easily, it could be considered to be more like a semantic unit. In contrast, the major planning unit of sentence production seems to be a syntactically defined semantic unit. Thus, it is not easy, or perhaps even possible, to say whether the speech planning unit is basically syntactic or basically semantic. The unit we have proposed is obviously semantic, in that it corresponds to a basic proposition. However, the conventional definition of that proposition is a syntactic one, in that it is a unit of speech containing or implying a verb. What is clear is that our results indicate that the deep structure clause is a primary unit of speech planning. As well as establishing the importance of the deep structure clause as a planning unit, the present study clearly demonstrated that decisions must be made about syntax during sentence production. Results showed that the processing load during nonembedded clauses is lower than that during other clauses, and that the load is lower in complements and adverbials than in relatives. Hence, it must be concluded that the difficulty of the output phase in production differs for clauses of different syntactic types, and therefore that some decisions about syntax are made during this phase. By contrast,

Planning Units and Syntax

in Sentence Production

49

although some planning for deep clauses apparently occurs during the end of their preceding clause, no evidence was found to indicate that the processing load at the end of clauses differs before clauses of different structure. Perhaps at the end of a clause general planning for content and structure takes place for the next deep clause, but some of the syntactic details of this next clause may not be worked out fully until it is actually being uttered. It is interesting to compare the present results with those of previous studies. Rochester and Gill (1973) found that there were less disruptions at the clause boundaries of relatives than at the boundaries of complements. Goldman-Eisler (1972) also found that there was less silent pausing before relatives than before ‘other’ subordinate clauses. In addition, her results showed that there was less pausing before subordinate than coordinate clauses. Thus, the results for pausing and disruption at the beginning of clauses appear to be the reverse of the present results for processing load during clauses. The present results, however, seem meaningful in light of the correspondence between amount of processing load during clauses and the degree of linguistic integration of these clauses with main clauses. In the deep structure of relatives, which have the greatest processing load during output, there is always an element that is identical with an antecedent in the matrix sentence. Other types of clauses do not require such an antecedent (cf., Huddleston, 1971, p. 141). For example, in I agreed with the decision that he made the relative pronoun that stands for the decision which is the object of made and which has been mentioned in the matrix sentence. However, in I agreed with the decision that he should go the word that is merely a complementizer, having no referential meaning. While relatives are more closely tied to the matrix clause than are other subordinate clauses, all subordinate clauses, because they are embedded, are more integrated with preceding clauses than are nonembedded units. The results of the present study, then, show that processing load during clauses increases with increasing clause complexity as indexed by degree of linguistic integration of clauses with their preceding clause. What needs to be explained is the apparently strange fact, indicated by previous studies, that amount of pausing and disruption at clause boundaries decreases as clause complexity increases. It may be that the amount of pausing and disruption is dependent not on the difficulty of planning the next clause, but on the degree to which what has just been said is a complete linguistic unit. It is, of course, the simpler less closely integrated clauses that are preceded by more linguistically complete units. Speakers may produce more pausing and disruption after these more complete units because there is less need to produce the next clause immediately and also, perhaps, more chance to change what is to be said. A further point is that processing load during clause output may decrease with decreasing linguistic

50


integration, not only because of the decreasing complexity of the clauses, but also because the greater pausing before the simpler clauses may allow more complete planning to take place and thus a subsequent ease of production. Whatever the explanation of the relationship between prior pausing and disruption, clause complexity and output load, it is clear that syntax does affect the difficulty of encoding throughout sentence production and thus that speakers do make syntactic decisions. One important aspect of the present study is that a new technique was used to overcome the problem inherent in pause studies, that planning taking place while speech is being produced cannot be investigated. The technique showed that speakers do plan and talk at the same time. This finding shows that pause studies should be supplemented with investigations using other methods, and also demonstrates the value of the “click” technique. A further interesting conclusion emerging from the present study was that the amount of disruption and silent pausing before clauses probably does not correspond with clause complexity and processing load during clauses. It seems that the function of pauses and hesitations in speech may not merely be for planning what is to be said next - their face validity as indicators of planning may be misleading.

Appendix

A

The coding of speech

and tone locations

Four small samples of the speech of different subjects talking on different topics are presented here to show more clearly the clause analysis and the classification of tone locations in regard to the three sets of clauses. Key for clause analysis.

sentence boundaries surface clause boundaries deep clause boundaries that are not surface clause boundaries Filled pauses, redundant words, repetitions, word choice mistakes truding sounds are shown in italics. i,’

Key for tone location: * location of the tone in speech

Tone locations are coded on three variables: i. clause segment b beginning of clause e end of clause

and

in-

PlanningUnitsand Syntax in Sentence Production

51

ii.

clause type A clauses which are both deep and surface structure clauses B deep structure clauses which do not correspond to surface clauses C surface structure clauses which contain more than one deep clause iii. clause position 1 (for A and C) the first surface clause in a sentence (for B) the first deep clause in a surface clause 2 (for A and C) the second surface clause in a sentence (for B) the second deep clause in a surface clause Thus, for example, the code eB1 would stand for any tone located at the end of a deep structure clause which did not correspond to a surface clause and which was the first in a surface clause.

Speech samples: i.

FAMILY LIFE

. . . [(urn my mother intelligent these

person

pe$%)

ibhA&e less respect

for) (I’m afraid)]

[(she’s not a very

at al;)] [(she’s a bit of a chain smoker)]

[(and she’s one of

(who

are intensely

cleaning the place up)] the p&e ii.

up)]

[(my

houseproud)]

[(and she get?%her

sister is niiyvery

[(she spends all her time /

annoyed

at anyone)

(who mucks

nice person either) (I’m afraid)] . . .

OLD PEOPLE

. . . [(The people they’re

r%m bad thing is) (that / and reacting reacting

lose too)]

[(*urn I’m just tryingB/lto

knowing)

(how

think of ah the other

deaf / and tend / t(; go blind)]

and urn you know a;d generally (as $yget

understanding

[(oh ;!k:e’s the sort of physical disabilities)

[(JOU know yE;et

a bad thing)] deteriorates)

to them / around you / or or or*rather

to you)]

types of *urn* things)]

you lose the facili?;1/b8%

(that you

[(that’s that’s

bad health get [(your health

older)] . . .

iii. SCHOOLS YOU HAVE ATTENDED advantages / of knowing kids) (that haven’t gone . . . [(ah it doesn’t ha;rlhe *eBl .pF”. mversity and that / and had all the advantages riaalb)] [They were onto more or less expectz$l

to go onto University)]

[(and they’re

they’re ill very

52


urn conservative greater advantage

in this way)]

[( *urn coeducational

/ th%%ngle-sex

schools)]

have a great much

school

...

iv. THE ROLE OF MEN AND WOMEN IN SOCIETY . . . [(ah *it’s a matter changes) cated)

/ of changing

(such that the channels

(and can be tr%$d

att&?es

are availible)

so much)

(that

the system

(so that women

can be edu-

managers) ] [(because

/ to become

*eBl

bLzc;ght up by management

are

say) (right he

/ to become

managers)]

is likely / to be a manager)]

[(and

put him through

this / to become

[( ylow the system ha?&& to change) (such that

the managers woman

managers)]

*$l?b5?ck

i’they

out a woman

/ and say) (right

[(they

managers

this this this and

I *w”8 give get this

/ to do such such such and such / to train h& / to be a manager)]

...

It can be seen from the speech samples that there are nine different coding combinations. bA1, eA1, bA2 and bC1, bC2 signify tones used for the analysis of the type A and C clauses respectively. bB 1, eB 1, bB2 signify tones used for the analysis of type B clauses. These last tones, however, were further coded according to whether they occurred in a deep clause in (a) the first or only surface clause in a sentence or (b) a subsequent surface clause. Although some of the tones in the speech samples are not coded because they did not occur in one of the relevant positions, they would have been used in other analyses of the study.

References Abrams,

K. and Bever, T. G. (1969) Syntactic structure modifies attention during speech perception and recognition. Q. J. exper. PsychoZ., 21, 280-290. Anderson, R. L. (1964) Missing-plot techniques. Biomet. Bull., 2, 4147. Bever, T. G., Carroll, J. M. and Hurtig, R. (1976) Analogy or ungrammatical sequences that are utterable and comprehensible are the origins of new grammars in language acquisition and linguistic evolution. In T. G. Bever, J. J. Katz and D. T. Langendoen (Eds.),An integrated theory of ling&tic ability. Sussex, Harvester Press. Boomer, D. S. (1965) Hesitation and grammatical encoding. Lang. Sp., 8, 148-158. Boomer, D. S. (1970) Review of F. Goldman-Eisler Psycholinguistics Experiments in spontaneous speech. Lingua, 25, 152-164. Clark, H. H. (1973) The language-as-fvtedeffect fallacy: A critique of language statistics in psychological research. J. Verb. Learn. Verb. Behav., 12, 335-359.

Planning

Units and Syntax

in Sentence

Production

53

J. A., Bever, T. Gand Garrett, M. F. (1974) The psychology of language: An introduction to psycholinguistics and generative grammar. New York, McGraw-Hill. Goldman-Eisler, F. (1968) Psycholinguistics: Experiments in spontaneous speech. London, Academic Press. Goldman-Eisler, F. (1972) Pauses, clauses, sentences. Lang. Sp., 15, 103-113. Hawkins, P. R. (197 1) The syntactic location of hesitation pauses. Lang. Sp., 14, 277-288. Holmes, V. M. and Forster, K. 1. (1970) Detection of extraneous signals during sentence recognition. Percept. Psychophys., 7, 297-301. Huddleston, R. D. (1971) The sentence in written English: A syntactic study based on an analysis of scientific texts. Cambridge, Cambridge University Press. Kahneman, D. (1973) Attention and effort. Englewood Cliffs, Prentice Hall. Kirk, R. E. (1968) Experimental design: Procedures for the behavioral sciences. Belmont, California, Brooks/Cole. Lazarus, L. M. (1973) The deep structure of the prenominal adjective in English. Linguistics, 102, 41-57. Rochester, S. R. and Gill, J. (1973) Production of complex sentences in monologues and dialogues. J. Verb. Learn. Verb. Behav., 12, 203-210. Scheffe, H. A. (1953) A method for judging all possible contrasts in the analysis of variance. Biometrika, 40, 87-104. Tanenhaus, M. K. and Carroll, J. M. (1975) The clausal processing hierarchy... and nouniness. In Papers from the parasession on functionalism, Chicago Linguistic Society. Chicago, University of Chicago Press. Taylor, J. (1948) Errors of treatment and comparisons when observations are missing. Nature, 162, 262-263. Valian, V. V. (1971) Talking, listening and linguistic structure. Unpublished doctoral dissertation, Northeastern University. Yates, F. (1933) The analysis of replicated experiments when field results are incomplete. Emp. J. Exper. Agricul., I, 129-142. Fodor,

Resume Cette recherche a 6te faite pour determiner, premierement si c’est la proposition de surface ou la proposition de base qui est la plus importante comme unit6 de planification dans le discours, et deuxiemement si des decisions syntaxiques se font pendant la production de la phrase. Les sujets entendent pendant qu’ils sont en train de parler, des tons auxquels ils doivent repondre en appuyant sur un bouton. Les temps de reaction servent d’indice du poids de calcul durant la production. On trouve que les temps de reaction correspondant a des fins de proposition en structure profonde sont plus longs que ceux qui correspondent i des debuts de propositions. Pour les temps de reaction correspondant au debut et a la fin des propositions de surface lorsque celles-ci ne coincident pas a des propositions de la base on ne constate pas de difference. On interprete ces rdsultats comme indiquant que les propositions de la structure profonde sont les unites principales et qu’une partie de la planification pour les propositions se produit a la fin de la proposition precedente. On trouve des temps de reaction differents pendant des propositions de structure syntaxique differentes. Ce qui est vu comme l’indice d’une influence de la syntaxe sur la production et est discuti en relation avec les travaux anterieurs sur les pauses et les interruptions des discours.