The space for case

JOURNAL o r VERBAL LEARNING AND VERBAL BEHAVIOR

12, 5 5 1 - 5 6 2 (1973)

The Space for Case I MICHAEL SHAFTO

Princeton Unwerstty

The psychological validity of Fillmore's (1971b) theory of case grammar was tested in two experiments. Experiment I used a concept-identification task to see if subjects could learn to recognize case-relations of nouns. Different rates of learning were found for four cases' Agent was easiest to learn, followed by Experiencer, Instrument, and Object. Scaling of confusion data revealed a two-feature cognitive structure for the "psychological" case system' living versus nonhvlng and active versus passwe Experiment II used a running recognition task to see if the predicate structure of verbs is a salient factor in encoding and long-term storage of sentences. Confusablhty of sentences was primarily a function of the similarity between the predicate structures of their main verbs. Three models for the access and comparison of sententlal information were proposed and tested against the data. The best-fitting model assumed similarity of encoded sentences m memory to be a function of the similarity between the predicate structures of their main verbs, rather than surface or "logical" grammatical functmns of their nouns. A theory o f case g r a m m a r developed by F i l l m o r e (1968a, 1971b) has influenced recent a t t e m p t s to m o d e l language-processing a n d storage o f semantic, p r o p o s i t i o n a l i n f o r m a t i o n (Simmons, 1972; R u m e l h a r t , g i n d s a y , & N o r m a n , 1972; Kintsch, 1972). The theory accounts syntactically for semantic relations o f nouns to clauses. F o r example, F i l l m o r e (1971b) provides an account, in terms o f a c o m m o n " d e e p " case relation, for the intuitively similar functions o f me in John strikes me as pompous a n d I in I regard John as pompous (cf. C h o m s k y , 1965, pp. 165ff.). W h i l e there are syntactic reasons for p o s t u l a t i n g distinct deep structure cases, each case has essentially a semantic function. A case is justified hngulstically because it accounts for a distract type o f semantic relationship between

a predicate (often a verb) and ltS a r g u m e n t s (often n o u n s ; Fillmore, 1968b, 1971a). The following set o f cases are the focus o f study in Experiment I below. These are f r o m F i l l m o r e (1971b), a n d all parenthesized page numbers refer to that article. Agent. The A g e n t case is the case o f the " p r i n c i p a l cause" o f an event (p. 253), a n d seems to involve notions o f b o t h causality a n d intention (or at least responsibility). F o r example, man m The man broke the window is m the A g e n t case. Experiencer. The experiencer o f a psychological event, a sensation, or an e m o t i o n is in the Experiencer case, for example John in John is sad, or me in The noise frightened me. Instrument. The I n s t r u m e n t is the case o f "the i m m e d i a t e cause o f an event, or, in the case o f a psychological predicator, the stimu1This work was supported by Research Grant No lus, the thing reacted t o " (p. 251). Some 19223 from the National Institute of Mental Health, United States Public Health Service, T. Trabasso, examples o f Instruments are hammer in The Principal Investigator; and by National Science hammer broke the window, movie in The movie Foundation Grant GB8023X, project on "Mathemat- was sad, a n d noise in The noise frightened me. ical Techniques in Psychology," H. Gulllksen, Object. The Object is the case o f " t h e entity Principal Investigator; and by Educational Testing which moves or undergoes c h a n g e . . . " (p. 251). Service. The author is indebted to Tom Trabasso, Simon Garrod, and E. Tory Higglns for critical It is used as a wastebasket. E x a m p l e s are window in The man broke the window, ball in comment and advice. Copyright © 1973 by Academic Press, Inc. 551 All rights of reproduction in ally form reserved. Printed m Great Bmtam

552

SHAFTO

The ball went over the fence, and accident in I imagined the accident. Source, Goal. The cases Source and Goal designate starting and stopping points, respectively. "Depending on the type of predicator, the Source and Goal are interpreted as earlier and later locations, earlier and later states, or earlier and later time points" (p. 250). For example, He went from the top of the hill to the cemetery gate, She changed from a 96-pound weakhng into a famous Jootball hero, The pageant lasted from sundown to midnight. Goal now also covers the former Benefactive case, as me in John did it for me or John gave me the piano, as well as the former Resultative or Factltive, as poem in I wrote a poem or brtdge in I constructed the bridge. Place, Time. Place and Time are distinct cases, even though spatial and temporal Sources and Goals are not distinct cases. (For a discussion of the syntax of Place and Time, see Fillmore, 1971b, pp. 258-259). Semantically, these two cases seem to be selfexplanatory. Although several psychological theorists have incorporated case-hke constructs into their models, the most convincing arguments in favor of case grammar have been provided by linguists (Halhday, 1967-68; Fillmore, 1968a; Chafe, 1970; Anderson, 1971). Psychological evidence which might be relevant to the models cited above has been indirect (e.g., Healy & Miller, 1970, 1971 ; Johnson-Laird & Stevenson, 1970: Garrod & Trabasso, 1973; Glucksberg, Trabasso, & W a l d , 1973). As Perfetti (1972) notes: "It is a fair assessment... to observe that the psycholingmstic implications of case grammar are only beginning to be investigated." The experiments reported here attempt to provide some direct evidence on the psychological validity of case grammar. This is done in two ways: Experiment I asks whether subjects can use case distinctions as a means for classifying sentences (e.g., those which involve Agents versus those which involve Experiencers). Experiment II asks whether

subjects store and recognize sentences in terms of abstract predicates underlying their verbs EXPERIMENT I

In Experiment I a concept-formation task is used to assess the correspondence between Fillmore's (1971b) case system and the intuitions of subjects with respect to types of relationships between nouns and clauses. It is argued that if Fillmore's proposed cases correspond to relationships which subjects find distinct and coherent, then subjects should learn to recognize instances of the caserelations. On the other hand, if subjects have difficulty discriminating the cases, then the cases must not correspond to clear psychological relations. In a concept-formation task subjects are asked to classify stimuli (e.g., sentences) into categories according to a rule. The main advantages for this task in studying case relations are that the experimenter does not need an explicit definition of the case relations, and that in order to solve the problem the subject must use features of case relations. Sentence length, voice, surface grammar, and so on are irrelevant, since each varies considerably within each category. It was decided, given the limitations of time and effort in creating instances, that the Agent, Experiencer, Instrument, and Object cases should be studied in detail because they seemed more centrally related to a wide variety of clauses. Instances of the other four cases were used as practice sentences. Method SubJects. The subjects were 12 Princeton Umversity undergraduates who volunteered to participate m " a psychohnguistlc experiment." SubJects were paid $3.00 for one 90-min session. Procedure andmatertals The materials consisted of a set of simple sentences. In each sentence one noun was underhned, indicating that its relation to the clause was to be considered. The subjects were tested individually. The following instructions were read to the subject by the experimenter:

SPACE FOR CASE This is a study of concept formation. For our purposes, a concept Is a rule for categorizing items according to some common feature or features. The items in this study will be sentences. In each sentence a word or phrase is underlined Read the sentence carefully. The concept you are to learn has something to do with the relation between the underlined word or phrase and the meaning of the sentence as a whole. To put it another way, the underlined word or phrase can be said to play a certain kind of role in the meaning of the sentence. The concept you are to learn has something to do with these different kinds of roles. In the following set of sentences, there are four different types of roles. As each sentence is displayed, read it, think carefully about its meaning, and consider the relation of the underlined word or phrase to the meaning of the sentence as a whole Then label the sentence as Type 1, 2, 3, or 4. Of course, at first you must guess, but after each trial you will be told the correct answer. In addition, if your first guess is not correct on a particular item, you will be given a second guess before being told the correct answer. This should allow you to focus in on the concept as you see more and more examples. Then 40 practice sentences were presented one at a time in a random order. The practice sentences consisted of 10 instances each of the Source, Goal, Place, and Time cases. The subject self-paced his classifications, and the experimenter told him whether or not his classification was correct. If his second classification was incorrect, the experimenter told him the correct class~fication. Immediately after feedback, the next sentence was presented. Following the practice problem, the experimenter read the following instructions: O K - - n o w the concepts will change, but the procedure will remain the same. To avoid confusion, start labelling the new concepts A, B, C, and D. The 120 Agent, Experiencer, Instrument, and ObJect sentences were then presented m a random order, using the same procedure as before. Thirty instances of each case were presented. Four examples of sentences used for each case are given in Table 1. Data. The 30 instances of each case were divided into 6 blocks of 5 according to order of presentation, and were scored for the percent correct classifications

553 TABLE 1

EXAMPLESOF SENTENCESFOR THE CASECONCEPTS IN EXPERIMENT I

Agent The honess snarled fiercely. The judge freed the prisoners. The ambush was planned by the mthtta. The audition was recommended by the composer.

Expertencer The edttor was shocked by the novel. The speech was heard by the dtplomat. The performer was calm. The noise frightened the baby.

Instrument The rats died from the potson. The movie was sad. The point is illustrated by several facts. The puppy was lovable.

Object The trunk was in the attic. The prelate was condemned by the church. The vegetables thawed slowly. The wind blew the papers away.

according to two crlterm The first-guess criterion counted a response correct only if the subject's first guess was correct; the second-guess criterion counted a response correct if etther the first or the second guess was correct

Results T h e s u b j e c t s q u i c k l y l e a r n e d t o label A g e n t s a c c u r a t e l y . T h e y a l s o l e a r n e d t o l a b e l Exp e r i e n c e r s , t h o u g h n o t as a c c u r a t e l y as A g e n t s . There was some evidence for learning Instrum e n t s , a n d little e v i d e n c e f o r l e a r n i n g O b j e c t s . Table 2 shows the mean percent correct i d e n t i f i c a t i o n s as a f u n c t i o n o f C a s e a n d T r i a l blocks. A within-subjects analysis o f variance, using arcsin transforms, yielded significant e f f e c t s - - f o r first- a n d s e c o n d - g u e s s d a t a , respectively-on

the following factors: Case,

F(3,33) = 14.2 a n d 2.98; Trials F(5,55) = 7.15 a n d 8.64; a n d C a s e x Trials, F(15,165) = 2.54 a n d 3.19. A l l effects w e r e s i g n i f i c a n t a t t h e 0.01

level e x c e p t t h e

Case

s e c o n d - g u e s s d a t a ( p < .05).

effect o n

the

554

SHAFTO TABLE 2 MEAN PERCENTCORRECTCASE CONCEPT IDENTIFICATIONS Blocks of 5 reals Case

1

2

3

4

5

6

Mean

Agent Experiencer

38.3 45 0

80.0 56 7

Instrument Object

35.0 30.0

40 0 33.3

71.7 53.3 25.0 41.7

78.3 48.3 51.7 51.7

81.7 70.0 46.7 45.0

80.0 61 7 53.3 40 0

71.7 55.8 41.9 40.3

Agent

56.7

91.7

Expenencer Instrument Object

65 0 75 0 65 0

88.3 71.7 85.0

88.3 85.0 56 7 83.3

88.3 73.3 76.7 83.3

95 0 91.7 83.3 83.3

91.7 93 3 78 3 66.7

85.3 82.8 73 6 77.8

First-guess data:

Second-gttess data

The ease of identifying each case relation was assessed by individual comparisons (Newman-Keuls, p < 0.05) on the means for the transformed data. The order of difficulty, from easiest to hardest, based on the first-guess data, was Agent > Experiencer > Instrument .- Object. The interaction can be attributed to different rates of learning within cases. The same pattern of results (necessarily) held for the second-guess data. There was, however, much stronger evidence for learning wlthin the Experience case. The data suggest that (a) Agent has strong intuitive appeal as a relational concept, (b) Experiencer also corresponds to a faMy clear intmtive relationship, and (c) Instrument and Object are relatively weak in their intuitive appeal. In order to obtain a more sensitive picture of the cognitive structure within the case system, a multidimensional scaling analysis was performed on the category confusions. For each subject two 4 × 4 confusion matrices were constructed, using either the first- or secondguess data. The rows of the confusion matrices represented the stimulus (case) categories, and columns the response categories. All cases were used an equal number of times, but

subjects were not constrained to use each response category an equal number of times. Therefore, each confusion matrix was normalized to percent of column sums. The group average normalized confusion matrices are given in Table 3. TABLE 3 CONFUSION MATRICESFROMEXPERIMENTI a Response Stimulus

A

E

I

O

62.0

10.7

19 2 8.9 10.0

53.3

9.1 10 6

First-guess data Agent Experiencer Instrument Object

19.5 16 4

47.7

98 14.1 30.8

32.6

45.4

81.0

3.3

3.7 7.1 8.2

80.8

5.3 7.2 83.1

5.6 6.1 10.1

4.4

78.I

Second-guess data.

Agent Experiencer Instrument ObJect

7.5 8.5

"Normalized percent of times a classificatory response was given to a case relatmn stimulus.

Each confusion matrix was considered a lower-corner submatrix of an 8 × 8 symmetric similarities matrix. These data were

SPACE FOR CASE

555

analyzed by nonmetric multidimensional scal- t a t i o n The four cases can be represented with ing. Solutions were computed in three and respect to two binary features, f l and f2. two dimensions by MDSCAL Version 5M, Experiencer and Object (and Agent and Ininvoking the L O W E R C O R N E R M A T R I X strument) contrast o n f 1, but not f 2 ;Agent and and SPLITBYGROUPS options (Kruskal & Experiencer (and ObJect and Instrument) conCarmone, 1969, pp. 20, 32). It is assumed that trast on f 2 , but n o t f l ; and the Agent-Object there is a common underlying configuration of and Experiencer-Instrument contrasts are on points (representing the stimulus and response b o t h f l and f2. categories) for all subjects, such that each An obvious interpretation of these features subject's similarities (the confusion data) can is t h a t f l is a living-nonliving distinction and be related to the interpoint distances by a f 2 is an active-passive distinction. Subjects monotone nonincreasing function; but a dif- have trouble distinguishing active and passive ferent monotone function may be used for roles when the noun is nonliving. In particular, each subject. By using this form of the al- they are unwilling to attribute active roles to gorithm, the four stimulus and four response nonliving nouns, so that Instruments are discategories were treated as eight separate points, placed toward Objects along the activeand the solutions were each based on 192 passive dimension. similarities, rather than 16 "average" values. The interpretation o f f l as hving-nonliving implies that subjects treat the tendency for Active (o) Fnrst Instruments and Objects to be nonliving as guess o" though it were a reqmrement. Therefore, they Agent may be learning an imperfect approximation Instrument to Flllmore's case system. Since the instances oe Lwing Non-living used in thin study included five living Instruments and ten living Objects, subjects learning eo Object Expenencer o to respond according to the suggested features should produce a distinctive pattern of errors. Poss~ve According to the interpretation o f f l , the (b) Second Achve subjects have the following solution rule: If guess the noun is living, then respond Agent or Instrument qP qD Experlencer (correct), otherwise respond InAgent strument or Object (incorrect with probability N o n - ILvlng Living 0.25). By following this rule, a subject would not misclasslfy an Agent or Experlencer as an % Experlencer % Object Instrument or Object, but would make the opposite mistake. Therefore, the probability Poss Ive that an instance is from the Instrument or FIG. 1. Multidimensional scaling solutions based on Object categories, given that it was classified as case concept confusions The configuranon m (a) is Agent or Experlencer, should exceed the based on first-guess data; that in (b), on second-guess data. Open circles represent snmulus categories, filled probability that it came from the Agent or Experiencer categories, given that it was circles, response categories. classified as Instrument or Object. In a briefer Figure 1 shows the two-dimensional sol- notation, Pr(I or O ] " A " or " E " ) > Pr(A or utions based on the first- and second-guess E ] ' T ' or "O"). The first-guess data show this pattern for 9 data. The root-mean-square stress for the of 11 subjects (p = .033, one-tailed sign test). former solution was 0.40; for the latter, 0.27. Figure 1 supports the following interpre- The median values of Pr(I or O [ " A " or "E")

556

SHAFTO

and Pr(A or E [ ' T ' or " O " ) were 0.27 and 0.19, respectively. More convincmg support for the livingnonliving interpretation o f f l comes from a subject-by-subject examination of the original response protocols. The pattern P r ( " A " or " E " [ living I or O) > Pr("A" or " E " I nonliving I or O) was found in 10 of 11 subjects (p = .006 by one-tailed sign test). The respective medians were 0.60 and 0.21. One characteristic of the proposed twofeature model is that the features c~in be identified with the two aspects of a n o u n clause relation. The active-passive dimension represents the contribution of the main verb's case-frame and accompanying prepositions. The living-nonlivmg dimension represents the contribution of the noun itself. For example, given T h e . . . killed the chicken, the relation of the surface subject to the clause is determined on the active-passive dimension (It m u s t be active), but It is indeterminate on the hyingnonliving dimension (poison would be an Ins t r u m e n t , f a r m e r would be an Agent). 2 EXPERIMENT II Experiment I provided data on some semantic features which underlie case relations. Experiment II examines a different aspect of case grammar and provides a test of an assumption of some models based on case-like notions (e.g., Rumelhart, Lindsay, and Norman, 1972). These models identify the organizing predicate of stored sentential information with the lexlcal root of the main 2 Sucl and Hamacher (1972), measuring latency to respond to a question about some relational aspect (e g , an adjecnve-noun relationship) of a previously heard sentence, obtained results remarkably consistent with those reported here. " . . . The data indicates that 'agent' and 'patient' are psychologicallyseparable umts and that agent holds processing or retrieval priority over patient. A stdl finer differentiation is made by adults who separate ease as defined by Fillmore. Smce the action role dtchotomy of agent-pattent subsumes case when further differentiation is made in terms of ammatehess, the reality of ammateness as a dimension of

semantic structure is supported" (emphasis added).

verb of the sentence. Surface information about voice, for example, may not be stored in long-term memory (Sachs, 1967). It is assumed, however, that the lexlcal verb-root is stored in long-term memory and is important in retrieval and matching to a question or test sentence (Garrod & Trabasso, 1973). While Experiment I asked about the psychological validity of some of the specific cases proposed by Fillmore, the present study asks about the role of case-like predicateargument relations in long-term memory for sentences. In other words, is there evidence for abstract predicates underlying verbs, regardless of their precise form? In what follows, "case" will be used to mean an "underlying predicate-argument relation," not necessarily one of those proposed by Fillmore. A running recognition task (Shepard & Teghtsoonian, 1961) was used to assess the relative confusabihty of three k i d s o f sentence-pairs: those having the same nouns assigned to common underlying case relations, but different surface grammatical functions; those having the same nouns assigned to common surface subject and object functions, but different underlying functions; and those using the same nouns, but in different surface and underlying functions. In a running recognition task, the subject is presented with a continuing sequence of items (e.g., sentences), and is required to retain as much information about the items as possible. Each item must be classified either "new" or " o l d " - - " o l d " meaning the same as a previously presented item. The high memory load helps ensure encoding and storage of items in long-term memory. The present study modified the Shepard and Teghtsoonian procedure in two ways: Meaningful material (i.e., sentences) was used, and no items were repeated, so that every recognition was a false recogmtion. Thus, the recognition rate was used as an index of the relative confusability between the test sentence and the encoded form of some previously presented distractor.

SPACE FOR CASE F o l l o w i n g F i l l m o r e (1968b, 1971a), t h e v e r b is

assumed

to

be

the

central

orgamzing

predicate o f a simple proposition. Lexically different verbs, however, can have similar or i d e n t i c a l p r e d i c a t e s t r u c t u r e s , d i f f e r i n g o n l y in t h e r u l e s g o v e r n i n g t h e c o r r e s p o n d e n c e between deep cases a n d

surface grammatical

f u n c t i o n s ( F i l l m o r e , 1968a). I f s o m e t h i n g like case

structure

is

the

basis

for

sentential

m e m o r y , t h e n case c o n g r u e n t sentences should be relatively task.

confusable

in

a

recognition

Method SubJects,. The subjects were 12 Princeton University undergraduates from the same population as the Experiment I subjects None had participated m Experiment I. They were paid $3.00 for one 90-ram session. Procedure and materials. The subjects were tested mdiwdually. The Instructions were: The purpose of this study is to obtain judgments of the "comprehenslbdlty" of a group of sentences, and at the same t~me to determine how well people can remember them. Read each sentence carefully If you find it awkwardly worded, highly improbable, or otherwise difficult to comprehend, place a check mark after It. After checking it for comprehenslNhty, study the sentence and try to remember its exact wording. Do not go on to the next sentence until told to do so. Whenever you recognize any sentence as the same as one you have already seen, put an " X " to the left of that sentence. There were 192 sentences, of which 120 were those used m Experiment I. No nouns were underhned m the present experiment. The subject stud~ed each sentence for 20 sec. A subject could confuse one sentence with another if the second was related in some way to the first. Suppose the first sentence was (1) The gangster owned the Cadillac The second sentence could be related to (1) in one of three ways If the verbs had similar underlying pre&cates, then the pmr of sentences was called Case Congruent Sentence (2) is Case Congruent to (1). (2) The Caddlac belonged to the gangster.

557

If the nouns were in the same surface grammatical functions (surface subject and object), but the verbs did not have similar underlying predicates, then the pair of sentences was called Noun-order Congruent. Sentence (3) is Noun-order Congruent to (1). (3) The gangster wrecked the Caddlac. Finally, if two sentences used the same nouns, but in different surface grammatical functions, and the verbs had different underlying predicates, then the pair was called Simply Related. Sentence (4) is Simply Related to (1). (4) The Cadillac approached the gangster. Note that sentences (2) and (3) are Simply Related, as are (3) and (4) Sentences (2) and (4) are Noun-order Congruent. Given a set of four related sentences, such as sentences (1)-(4), there were three kinds of relatedness d~stnbuted over six related pairs. Any pair of related sentences used the same nouns and lexically different verbs They were all in the active voice. A total of 192 sentences were rated for comprehenslblhty and checked as "old" or "new" by each subject. No two sentences were ~dentlcal. These sentences were grouped into four blocks of 48 sentences each. Within a block, 24 sentences were fillers, in the sense that none of them were related to any other sentence in any block. There were 24 sets of related sentences, one of which was illustrated by sentences (1)-(4). The verbs used for the two Case Congruent sentences in each set are given m Table 4. Related sentences were distributed over blocks, so that pairs of sentences could be related only between, never within blocks The first block contained all new sentences, and false recognitions on related pairs could occur only in Blocks 2-4. For each set of four related sentences, one sentence from the Case Congruent pair was chosen randomly and assigned to the first block. The order of assignment of the remaining three sentences was counterbalanced over Blocks 2-4, yielding 2 x 6 = 12 different orders of presentation Of these, six orders were unique with respect to the kind of relatedness of sentence pairs between blocks. Assignment of related sets of sentences to orders of presentation was counterbalanced across subjects. Within a given block, filler and test sentences were mixed in a different random order for each subject. The number of sentences intervening between the presentation of a sentence in one block and the presentation of a related sentence in the next block was a random variable with mean 48 and standard deviation 20. The correspondmg values for time lag were approximately 16 mm and 6.5 min Data. The dependent variable of interest was the percent false recognitions for the four test sentences

558

SHAFTO

in each condmon, conditions being defined by umque Orders of Presentation (1-6) x Blocks (1-4). TABLE 4 CASE-CONGRUENT,LEXICALLYDIFFERENT VERBS, EXPERIMENTII 1. 2. 3. 4. 5. 6. 7 8 9 10. I 1. 12. 13 14 15 16. 17. 18. 19. 20. 21. 22. 23. 24.

rob-steal detest-disgust cause-result (from) capture-surrender (to) speak (to)-hsten (to) own-belong (to) show-look (at) send-receive dehght-enjoy loan-borrow trouble-worry (about) teach-learn frighten-fear gwe-get command-obey offer-accept please-hke impress-admire buy-sell kdl-die (from) tell-hear (from) convmce-beheve lead-follow annoy-dishke

Results Editing. Subjects rarely judged a sentence difficult to comprehend. Overall, only about two percent of a possible 2304 sentences were checked as "difficult." Therefore, variations in item comprehensibility could not have been a major factor in the results of Experiment I. False recognitions. The false recogmtion rate for test sentences in Block 1 was equal to that for filler sentences over all blocks (about 0.4~). The average rate for test sentences in Blocks 2-4 was about 7.8 ~ . A within-subjects analysis of variance, using arcsin transforms of the data from Blocks 2-4, indicated that the main effect for Blocks was not significant, F(2,22) = 2.35, p > .05; and that the Order of Presentation of related pairs had no significant effect, F < 1.0. Of interest was the significant Blocks x

Order interaction, F(10,110) = 3.79, p < .01. The pattern of cell means indicated that this interaction was due to the fact that order o f presentation determined the kind of relatedness between a test sentence and previous related sentences, and the effect of Block (i.e., number of previous related sentences) depended on the kind of relatedness. In particular, the most important factor determining false recognition rate was whether or not a previous sentence was Case Congruent to the test sentence. The average false recognition rates in Blocks 2-4, respectively, were 9.4, 21.9, and 15.4~ when the test sentence was Case Congruent to a previous sentence, and 3.2, 4.2, and 5.8~o when it was not. Subsequent tests of hnear combinations of the cell means within the two-way interaction were used to assess the effects of the number of previous sentences related in each possible way to the test sentence. The effect for number of Case Congruent sentences was significant, F(1,11) = 17.4, p < .01, but those for Nounorder Congruent and Simply Related sentences were not, F(1,11)= 4.2, p > .05, and F < 1.0, respectively. These results support the proposition that verb predicate structure may be an important aspect of long-term memory for sentences. Moreover, verbs may be stored in a more abstract form than as a lexical item minus voice and other surface information. False recognitions in this study could not be attributed to verb lexical identity, since no two verbs w~thm a related set were lexically identical. The surface subject and object roles were also reversed for the Case Congruent sentences, which were the most confusable. Since all related sentences were in the actwe voice, the logical subject and object roles were also reversed in these sentences. Therefore, identity of nouns in surface or logical grammatical functions is not necessary to produce confusions. Hence, confusions among Case Congruent sentences most likely resulted from similarities in the underlying predicate structures of their verbs.

SPACE FOR CASE

Recognition Model Analysis The false recognition data are now examined with the help of three alternative models. The classification of a given test sentence as "old" is assumed to be a decision based on a comparison of the encoded form of the test sentence with the representation in memory of a sentence previously seen. Assume that, when the test sentence is encoded by the subject, the encoded form of the sentence acts as an access cue, that is, provides information which permits the direct access of any prevaous sentence whose representation an memory is simdar to the cue. The representation which is accessed is compared to the encoded form of the test sentence, and a same-different decision is made. In other words, the direct access process automatically provides the most similar sentence accessible an memory, and the decision is whether or not it is similar enough to be called "same." Although the present data do not permit a detailed study of these processes, they do provide a basis for testing three alternative hypotheses regarding the nature of the similarity function on which the direct access process is supposed to be based. These three hypotheses will be designated the Case, Subject, and Recency models, since they assume the basis for the direct access process is, ceterisparibus (see Assumption 3 below), casestructure, the surface grammatical subject, and the time elapsed (or the number of intervening sentences) between the presentation of two sentences, respectively. Let trials be indexed by t and let sentences, in order of presentation, be indexed by k. A sentence presented on Trial t is assumed to be available on all subsequent trials, but not necessarily accessible. Let a(k,t)= 1 if sentence Sk IS accessible on Trial t, otherwise a(k,t)= O. Let s(Sk, SO be a non-negative function representing the similarity between the encoded forms of sentences Sk and St. The assumptions shared by all three models are: 1. There is a constant probability p that a

559

sentence presented before Trial t is accessible on Trial t: Pr[a(k,t)= 1] = p if 1 < k < t; = 0 otherwise. 2. Of those sentences which are accessible on Trial t, the one most smfilar to St is chosen for comparison. Formally, Sentence i (S,) is accessed for comparison, such that a(t, t) s(S,, S0 -= max[a(k, t) s(Sk, St)]. If two accessible sentences are equally simdar to St, then one of them is chosen randomly for comparison. 3. The simdarity between any two related sentences is greater than the similarity between any two unrelated sentences. The models are differentiated only by their assumptions about s(Sj,Sk) given that sentences Sj and Sk are related. For each model, the assumptions about order of access are: Case model: Case Congruent > Nounorder Congruent = Simply Related > Unrelated. Subject model: Noun-order Congruent > Case Congruent = Simply Related > Unrelated. Recency model: Related > Unrelated and, gwen that more than one prior sentence is related to St, the most recently presented is accessed first, that IS, s(Sj, St)
Case. pC + (1 - p ) p O + (1 _p)2 B. Subject: pO + (1 - p) pC + (1 _p)Z B. Recency : pO + (1 - p) pC + (1 - p ) : B.

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SHAFTO

Subject: pO + .5[(1 - p)p + (1 -p)Zp](C + N) + (1 _ p ) 3 B. Recency:pN + (1 - p ) p O + (1 -p)ZpC +

If the subject has seen one Case Congruent, one Noun-order Congruent, and one Simply Related sentence (m that order) then the predictions are

Case pC+ .5[(1 - p ) p + (1 - p ) 2 p ] ( O + N)+ (1 - p ) 3 B.

(1 - p)3 B. Each model generates a prediction equation f o r e a c h o f t h e 24 m e a n s

in t h e

original

TABLE 5 OBSERVED AND PREDICTED MEAN PERCENT FALSE RECOGNITIONS (FROM ThE 24 CELLS IN THE ORIGINAL DESIGN, EXPERIMENTII) Percent false recognmons Number of each type of previous related sentence

Predicted by each model

Case

N-order

Simply

Observed

Case

Subject

Recency

0 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 1 1

0 0 0 0 0 0 1 1 0 0

1 1

0 0

0 0

0 0 0 1 1 0 0 0 0 0 I

! 1 1 0 1 0 I 1 1 1 1

1 1 1 1 0 2 2 2 2 2 I

1

1

1

0 .0 .0 2.1 .0 .0 .0 2.1 6.3 4.2 125 6.3 4.2 2.1 104 20.8 22.9 .0 6.3 6.3 2.1 8.3 14.6 10.4

.0 .0 .0 .0 .0 .0 1.1 1.1 6.0 6.0 12.8 12.8 5.6 56 56 13.4 16.3 1.8 5.3 5.3 5.3 5.3 16.1 16.1

.5 .5 .5 .5 .5 .5 1.1 1.1 7.3 7.3 7.2 7.2 75 7.5 7.5 5.1 90 1.2 7.5 7.5 7.5 7.5 8.5 8.5

.4 .4 .4 .4 .4 .4 1.0 1.0 5.0 5.0 13.0 130 5.2 5.5 5.2 12.6 16.6 1.6 5.8 5.5 6.1 5.5 16.3 160

TABLE 6 LEAST-SQUARES PARAMETER ESTIMATES AND PERCENT VARIANCE ACCOUNTED FOR BY THE MODELS

Parameters Model

p

C

O

N

B

Percent variance accounted for

Case Subject Recency

0.413 0.746 0.075

0.309 0.095 1.672

0.145 0.096 0.613

0.027 0.012 0.086

0.000 0.005 0.004

75.0 38.1 73.6

SPACE FOR CASE

6 × 4 design. Least-squares estimates of the parameters were computed for each of the models, and the goodness-of-fit was assessed by the percent variance among the 24 means accounted for by the model. The observed and predicted means for all three models are shown in Table 5. Table 6 gives the parameter estimates for each model and the percentage of variance accounted for. The Case and Subject models yield reasonable parameters, as seen in Table 6, while the Recency model yields an impossible value for C. The Case model accounted for about 75 of the variance among the means, while the Subject model accounted for only about 38 ~ . Furthermore, the values of C, O, N, and B for the Case model were consistent with the model's assumptions about the direct access similarity function. That is, sentences assumed to be more similar with respect to access were also more confusable during the comparison stage. Given that a sentence was accessed, the probability of a confusion based on case was about twice that of a confusion based on noun-order. The combination of reasonable parameters and relatively high percentage of varianceaccounted-for clearly favors the Case model over the two alternatives proposed here. GENERAL DISCUSSION

Two experiments were performed to test possible psychological implications of Fillmore's theory of case grammar. The results of Experiment I indicated that the Agent and Experiencer cases were easier for subjects to learn to recognize than were the Instrument and Object cases. Therefore, it was concluded that the former two cases, but not the latter two, correspond to intuitively clear types of semantic relations between nouns and the clauses they appear in. It seems likely that the latter two cases encompass a variety of notionally distinct semantic relations, even though there may be syntactic criteria for combining them into just two deep cases.

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Multidimensional scahng analysis of confusions among cases revealed a two-dxmensional cogmtive structure underlying the subjects' behavior in the classification task. The two independent features were (a) whether the noun occupied an active or a passive role in the clause, and (b) whether the noun named a living or a nonliving object. Thus, the independent contributions of the verb and the noun had to be combined by the subject in order to solve the problem. The results of Experiment II indicated that sentences with the same underlying predicate structure were relatively more confusable in a running recognition task than were sentences with identical surface subjects and objects or sentences which simply used the same nouns. No pair of sentences had lexically identical verbs. Therefore, lexlcal identity of main verbs is not necessary to produce sigmficant confusability among sentences. Three models for the cognitive processes involved in the recognition task were tested. The best model was the one that assumed the encoded form of a sentence depends on the underlying predicate structure of its main verb, and that a sentence stored in long-term memory can be accessed according to its abstract predicate structure. This experiment was directed toward a more general question than that of Experiment I. The results are compatible with a number of theoretical proposals, including those o f Johnson-Laird (1970), Halliday (1970), Fillmore (1971c), Leech (1970), and Lakoff(1971). The results demonstrate that theories based on the lexical verb, surface subject-object relations, or even logical subject-object relations are insufficient to describe the encoded form of a sentence in long-term memory. REFERENCES ANDERSON, J. M The grammar o f case: Towards a locahstlc theory. Cambridge: Cambridge Umverslty Press, 1971. CHAFE, W L. Meaning and the structure o f language. Chicago: Umversity of Chicago Press, 1970. CHOMSKY, N Aspects o f the theory o f syntax Cambridge, Mass. : M.I T. Press, 1965.

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FILLMORE, C. J. The case for case. In E. Bach & R. T. Harms (Eds.), Universals m linguistic theory. New York. Holt, Rmehart, and Winston, 1968(a) FILLMORE,C. J. Lexical entries for verbs. Foundationsof Language, 1968, 4, 373-393.(b). FILLMORE,C. J. Types of lextcal information. In D D Steinberg & L. A. Jakobovlts (Eds), Semantics" An interdisciplinary reader in philosophy, hngutsncs and psychology. Cambridge: Cambridge Umverslty Press, 1971.(a). FILLMORE, C. J. Some problems for case grammar In C. J. Fdlmore (Ed), WorkmgPapers mLmguistles, No. 10. Department of Linguistics, The Ohio State University, 1971.(b). FILLMORZ, C. J. Verbs of judging: An exercise m semantic description. In C. J. Fillmore & D T. Langendoen (Eds,), Studies in lingmsttc semantics. New York: Holt, Rmehart, and Wmston, 1971(c). GARROD, S, & TRABASSO, T A dual-memory mformation processmg interpretation of sentence comprehension. Journal of Verbal Learning and Verbal Behawor, 1973, 12, 155-167. GLUCKSBERG,S, TRABASSO,T., & WALD, J. Lmgulsttc structures and mental operations" An reformationprocessing analysts of sentence comprehension. Cognitive Psychology, 1973 (in press). HALLIDAY,M. A. K. Notes on transitivity and theme in Enghsh. Journal of Linguisncs, 1967, 3, 37-81, 199-244; and 1968, 4, 179-215. HALLIDAY,M. A. K. Language structure and language function. In J. Lyons (Ed), New horizons m hngutsttcs. Baltimore: Penguin, 1970 HEALY, A. F , & MILLER, G. A. The verb as the determmant of sentence meamng. Psychonomic Science, 1970, 20, 372. HEALY, A. F., & MILLER, G. A. The relative contribution of nouns and verbs to sentence acceptability and comprehensibility Psychonomlc Science, 1971, 24, 94-95 JOHNSON-LAIRD,P. N. The perception and memory of sentences. In J. Lyons (Ed), New horizons m lingmsttcs. Baltimore: Penguin, 1970.

JOHNSON-LAIRD,P N., & STEVENSON,R Memory for syntax. Nature, 1970, 227, 412. KINTSCH, W. Notes on the structure of semantic memory. In E. Tulvmg & W. Donaldson (Eds.), Orgamzanon of memory. New York: Academic Press, 1972. KRUSKAL, J B., & CARMONE, F. HOW to use M-DSCAL (Version 5M) and other useful information. Unpublished manuscript, Bell Telephone Laboratorles, Murray Hill, N.J., 1969. LAKOFF, G. On generatwe semantics. In D. D. Steinberg & L. A. Jakobovlts (Eds.), Semantics. An mterdtsciplmary reader m phdosophy, hnguistics, and psychology. Cambrtdge. Cambridge Umverslty Press, 1971. LEECH, G N Towards a semantic descripnon of Enghsh. Bloommgton: Indiana Umversity Press, 1970. PERVETTI, C. A. Psychosemantlcs. Some cognxtwe aspects of structural meaning Psychological Bulletm, 1972, 78, 241-259. RUMELHART,D E., LINDSAY,P. H., & NORMAN,D A. A process model for long-term memory. In E. Tulvlng & W. Donaldson (Eds.), Orgamzatton of memory New York: Academic Press, 1972. SACHS, J S. Recogmtlon memory for syntacnc and semantic aspects of connected discourse Perceptton and Psyehophysics, 1967, 2, 437-442. SrtEeARD, R. N , & TEGHTSOONIAN,M. Retention of information under conditions approaching a steady state. Journal of Experimental Psychology, 1961, 62, 302-309. SIMMONS, R. F. Some semantic structures for representing Enghsh meanings In R O. Freedle & J. B Carroll (Eds), Language comprehension and the aeqmsttton of knowledge Washmgton, D.C. : Winston, 1972. SucI, G. J., & HAMACHER,J H Psychological dimensions of case m sentence processmg: Action role and ammateness. International Journal of Psychohngmstlcs, 1972, 1, 34-48 (Received March 21, 1973)