Learning Argument Structure Generalizations
Children’s Early Use of Verbs in the Bates Corpus
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- Bu səhifədəki naviqasiya:
- Accounting for the high frequency
- Accounting for the high frequency in the input
- Corpus evidence of construction as reliable predictor of overall sentence meaning
- Experimental evidence of construction as reliable predictor of overall sentence meaning
- Category Validity
Children’s Early Use of Verbs in the Bates CorpusDatabase In order to examine more closely children’s early uses of particular constructions, we investigated a corpus of children’s early speech. The main language corpus used in this study is the Bates corpus (Bates, Bretherton, & Snyder, 1988) on the Child Language Data Exchange System (CHILDES) database (MacWhinney, 1995). This corpus contains transcripts from the Bates/Bretherton Colorado longitudinal sample of 27 middle-class children, 13 boys and 14 girls at age 20 and 28 months. There are transcripts for 15 minutes, equally divided into three types of mother-infant interaction: free play, reading of the book Miffy in the Snow, and snack time. Data collection and coding The speech of all 27 children at 28 months and the speech of 15 mothers to their children aged 28 months was extracted from the Bates et al. transcripts. Utterances were collected and hand-coded independently by the second two authors and then combined into one full list. Disagreements were resolved through discussion with the first author. Agreement between the two independent coders was 96.5% initially and 100% after discussion (n = 840) for classifying children’s utterances by construction type. The speech of fewer adults was analyzed because there were more data points for each adult; i.e., parents spoke more than the children. A second set of 7 mothers was coded separately by the second author in order to determine whether there was any bias in our sample of 15 mothers. The same trends were noted in the second sample so we concluded there was no bias and we used the smaller sample that had been coded independently by two coders. Word and sentence segmentation decisions were respected. All complete child and adult utterances containing a verb were included in the coding. Four columns were used to describe every utterance: construction, verb, speaker+situation+age, and the actual utterance. Each utterance was coded in this way for verb and construction pattern. All patterns were coded, but three patterns are focused on in this paper: VL: (Subject) Verb Location VOL: (Subject) Verb Object Location VOO: (Subject) Verb Object-1 Object-2
Classifications were based primarily on form: categorizing an utterance as an instance of the VL pattern required that there be a verb and some type of locative phrase: a preposition phrase indicating location, a particle indicating location (e.g., down, in), a locative (there, here), or some combination. Thus, She lived in Pennsylvania and She went there would both be considered an instance of the VL formal pattern while She lived with her sister would not be because “with” is not a locational preposition. VOL required a verb with an object NP and some type of locative: a preposition phrase indicating location, a particle indicating location (e.g., down, in), a locative (there, here), or some combination. VOO required a verb and two NPs. We ignored variable word orders correlated with questions, topicalizations, etc. Questions such as What did she put in his eyes?, for example, were considered instances of the VOL pattern. Utterances considered unacceptable or ungrammatical to adults were included in the coding. We did not attempt to distinguish arguments from adjuncts because we did not want to assume the 28 month old children had mastered the distinction. A sample from the coded transcript is given below:
Table . Sample from the Bates et al. (1988) corpus Results and Discussion In the children’s speech we find that the verbs which correspond to a construction’s meaning as given in Table were overwhelmingly the most frequent verbs used in that construction.7 For example, the VL construction, exemplified by the sentence, I went into the store, has roughly the meaning corresponding to that of the verb go as used in that pattern: (Subj)VOblloc X moves Yloc“go” Correspondingly, the verb go} accounted for a full 54.02% (121/224) of the instances of that construction in the children’s speech. Other verbs occur in the construction, but with much less frequency:
A similar pattern emerged in the case of the VOL construction, exemplified by the sentence, I put the book on the table. This construction has semantics closely related to the lexical semantics of the verb put} (cf.Goldberg, 1995); it turns out that put} accounts for a full 31.37% (16/51) of the instances of the construction in the children’s speech. (Subj)VObjOblloc X causes Y to move Zloc“put” Again, other verbs appear in the construction, but with markedly less frequency:
The ditransitive or VOO construction, illustrated by the sentence Pat gave Chris a book, is closely associated with the semantics of transfer, or the meaning of the lexical verb, give (seeGoldberg, 1992, for discussion of this and slight variations of constructional meaning, as well as general references; Goldberg, 1995). (Subj)VObj1Obj2 X causes Y to receive Z “give” Only 6 instances of the VOO construction were found in the children’s speech in the Bates et al. corpus. These included 2 instances of give, 2 of make, and 2 of bring. This paucity of data is due to the fact that the VOO construction is only just beginning to be learned at 28 months. We therefore examined data collected by by Gropen et al. (1989) from longitudinal data in the Brown (1973) corpus of Adam, Eve, and Sarah together with MacWhinney’s (1995) data on Ross and Mark. Gropen et al. searched these corpora for instances of the VOO construction. Adam was recorded in 55 two hour samples taken every 2-4 weeks between age 2;3 and 4;10. Eve was recorded in 20 two hour samples taken every 2-3 weeks between age 1;6 and 2;3. Sarah’s speech was recorded in 139 one hour samples taken at 2-19 day intervals between the ages of 2;3 and 5;1. Ross and Mark were both recorded by their father Brian MacWhinney in 62 samples of varying sizes at varying intervals, Ross between the ages of 2;6 and 8;0, and Mark between the ages of 0;7 and 5;6. Below is a table of the age of the earliest recorded use of the VOO construction and the earliest recorded age at which give was used ditransitively. The average age at which the first VOO use was recorded is 2;8, or 31 months. In each case, give was either recorded as early as any other verb in the VOO construction, or within one month of the earliest use of the VOO construction.
Table . Initial uses of ditransitive in the Brown (1973) and MacWhinney (1995) corpora Looking at the most frequent verbs to appear in this construction, we find that, as seen in Table , give is the most frequent for the majority of children. In the case of one child, Mark, we find tell to be just slightly more frequent than give.8
Table . The most frequent verb in ditransitive (VOO) construction based on Gropen et al. (1989) The most frequent and early acquired verb corresponds to the semantic prototype of the construction. As discussed above, we know that frequency and order of acquisition play key roles in category formation in that training on prototypical instances, frequently and/or early, facilitates category learning (Bruner, Goodnow, & Austin, 1956; Kruschke, 1996; Maddox, 1995; Nosofsky, 1988). While we have not demonstrated a causal relationship, we speculate that the semantics associated with a pattern arises because of the early and very frequent use of a verb in the pattern. For example, after using many sentences with put in the VOL construction as in , children come to associate the meaning of put with the construction even when the verb is not present as in (6): She put a finger on that.
The result is that the meaning of roughly “X causes Y to move Zloc” comes to be associated with the Subj V Obj Obl formal pattern. It should be noted that it is not a logical necessity for forming a constructional category that there should be a single verb with frequency far greater than other verbs. The correlation between form and meaning could in principle be learned by noting the association of form and meaning across several distinct verbs, each with relatively low frequency. Strikingly asymmetric frequencies are found in the data, however, with one verb having far greater frequency than other verbs for each of the constructions discussed here. Given the facts about general categorization reviewed in section , it is reasonable to assume that the especially high frequency makes the learning of the correlation that much easier: the meaning associated with the construction requires minimal abstraction from the semantics of the verb as used in the construction. The highly frequent verb serves as a readily available prototype with which other verbs may be associated.
The question arises as to why these verbs are used more frequently in these constructions by children. One factor of course is that these verbs are among the most frequent verbs in the language at large {Carroll, 1971 #36}. More relevant to the current discussion is the fact that the same pattern described above in children’s speech also holds in adult speech. That is, the use of a particular construction is typically dominated by the use of that construction with one particular verb. For example, go accounts for a full 38.5% of the uses of the VL construction in the speech of mothers addressing 28-month-olds in the Bates et al. (Bates et al., 1988) corpus. This high percentage is remarkable since this construction is used with a total of 39 different verbs. Percentages of light verbs in particular constructions are given below in Table .
Table . 15 Mothers’ use of verbs in Bates et al. (1988) corpus9 We know from previous studies that children’s use of verbs is highly sensitive to their mothers’ use of the verbs (Choi, 1999; De Villiers, 1985; Naigles & Hoff-Ginsberg, 1998); thus it is not surprising that the high frequencies of the children’s use reflects the high frequencies of the mothers’ use.
The fact that go, put and give are so frequent in the input raises the question as to why that should be so. There seem to be two reasons. First, if we compare for example, go with amble, or put with shelve, it is clear that go and put are more frequent because they apply to a wider range of arguments and therefore are relevant in a wider range of contexts (Bybee, Perkins, & Pagliuca, 1992; Heine, 1993; Zipf, 1935). In addition, each of the main uses of these verbs designates a basic pattern of experience, for example, someone causing someone to receive something (give), something causing something to move (put), or someone acting on something (do). These meanings are readily accessible to the child, since they involve concrete actions. Note that the verb be, while being generally applicable and in fact highly frequent in adult language, is learned rather late by children. This is likely because the meaning contributed by be is less easily accessible, since it is so abstract and dilute. Thus the verb meanings need to be accessible as well as highly frequent in the input in order to be frequently produced in early child language (Slobin, 1985). “Pathbreaking verbs” analysis The present proposal focuses on how the semantics associated with argument structure patterns may be learned. In a related proposal, Ninio (1999) notes that the early use of certain verbs may allow the child access to initial syntactic generalizations as well.10 Ninio analyzes early uses of SVO and VO patterns in two Hebrew-speaking populations: 15 children in a longitudinal study and 84 18-month-old children in a cross-sectional study.11 She notes that children often begin using a single verb with a direct object long before a direct object appears with other verbs; moreover, she notes the overwhelming tendency for these “pathbreaking” verbs to be drawn from the set of general purpose or light verbs. In particular, in both the longitudinal and cross-sectional studies, the children tended to use verbs meaning “want,” “make/do,” “put,” “bring,” “take out,” or “give” before other verbs were used. In the longitudinal study, Ninio further observes that SVO and VO patterns were initially produced with only one or at most a few verbs for a prolonged period lasting between 2 and 15 weeks. More and more verbs came to be used in an exponentially increasing fashion; that is, there seemed to be more facilitation after ten verbs than after five and so on. She suggests that this increase stems from the fact that children gradually abstract a more general and purely syntactic pattern on the basis of the early verbs, and that the growing generalization allows them to use new verbs in this syntactic pattern more and more easily. On both Ninio’s account and the present proposal, patterns are learned on the basis of generalizing over particular instances. As vocabulary increases, so does the strength of the generalization, making it progressively more and more easy to assimilate new verbs into the patterns. With Ninio, it is argued here that the instances that play an initial, crucial role are those involving light verbs. The two accounts complement each other in that Ninio proposes that light verbs lead the way in the early acquisition of syntax, and the present proposal emphasizes the role of light verbs in the acquisition of the semantics associated with basic syntactic patterns. It may well be that early uses of light verbs provide the foundation for both initial syntactic and semantic generalizations, and thus provide a route to the acquisition of form and meaning correspondences: i.e., constructions. The accounts differ in their explanations as to why light verbs should be learned so early. While Ninio notes that light verbs are highly frequent and pragmatically relevant, she argues that the tendency for light verbs to be used early in the VO and SVO patterns stems largely from a high degree of semantic transitivity in these light verbs. She states, “The ‘pathbreaking verbs’ that begin the acquisition of a novel syntactic rule tend to be generic verbs expressing the relevant combinatorial property in a relatively undiluted fashion; this is what makes them such good candidates for acquisition” (1996, ); these verbs are argued to necessarily express “a fundamental, unalienable, core notion of [semantic] transivity” (Ninio, 1996; see alsoNinio, 1999, ). This proposal requires that the light verbs that appear in the (S)VO pattern early are all highly semantically transitive, since it is this semantic property of the verbs that is argued to encourage their appearance as syntactically transitive verbs. However, as Ninio herself notes, many of the early light verbs are not highly semantically transitive according to traditional criteria; i.e., they do not involve an agent acting on, or changing the state of a patient argument (see e.g.,Hooper & Thompson, 1980). For example, the light verbs, want, see, get and have appear among the very first verbs in Ninio’s corpus, and yet they are not highly transitive according to traditional criteria. Ninio discusses this discrepancy at some length and argues that a notion of unmarked, “core” or “inalienable” transitivity is at issue, and not the traditional understanding of semantic transitivity which may be expressed with some type of morphological marking.12 In describing what the notion of “core” transitivity involves, she notes that many of the light verbs describe situations that are more likely to result in a change in the subject argument than the patient argument (Ninio, 1996, ; 1999, ). In fact, Ninio observes that many early transitive utterances are “semantically speaking...in fact not very far away from intransitive sentences” (Ninio, 1996, ). While we clearly need to be sensitive to descrepencies between child and adult perception of events, it remains difficult to see how verbs that are acknowledged to be fundamentally similar to intransitive verbs could be actually the unmarked transitive verbs. In support of the claim, Ninio argues that the children’s first transitive verbs are the verbs that typically get grammaticalized as transitivity markers cross-linguistically. But while light verbs do clearly often get grammaticalized as various kinds of auxiliaries (Bybee et al., 1992; Heine, 1993), their role as transitivity markers per se is far less clear. As examples of transitivity markers in Indo-European languages, the perfect marker “have” and the set of Indoaryan complex verbs that involve a light verb concatenated with a noun or other host are cited. However, the “have” perfect marker, (e.g., Italian avere), applies to agentive intransitive verbs as well as to transitive verbs. And the light verbs involved in complex predicates typically include a full range of light verbs. For example, “become” (shodan), “come” (âmad), and “go” (raftan) all serve as light verbs in complex predicate formation in Persian alongside transitive verbs (e.g.,Goldberg, 1996; Windfuhr, 1979). Do and give are two light verbs that often become grammaticalized as transitivizers or causativizers, but give is actually acquired later than many other verbs (cf. Table ), most likely because of its more complex syntax. Other transitivizer or causativisers tend to be directionals (Song, 1996; Wolfenden, 1929) or verbs meaning “to cause” (Givón, 1971). Lacking reason to suppose that the first learned transitive light verbs are necessarily semantically more transitive than other verbs, the proposal ultimately does not explain why light verbs should appear with transitive syntax before other verbs. On the present account, meanings of constructions emerge directly from generalizations over particular verbs. Since the transitive pattern appears with a range of highly frequent verbs, including verbs with low semantic transitivity such as see, get and want, the association of semantic transitivity with simple syntactic (S)VO status is predicted not to be overwhelmingly strong. In fact this is the case, as the (S)VO pattern is associated with a very wide range of meanings (e.g.,Davis, 1996; Dowty, 1991). As discussed in the previous section, the fact that light verbs are used so early and frequently results from their high frequency in the input language and their accessible meanings. The high frequency in the input in turn stems from their generally applicable and highly relevant meanings. The present account generalizes to other light verbs that are not transitive, but are also very frequent, and can be seen to form the basis of argument structure meaning. For example, we have seen that the verb go is the most frequent verb used in the VL construction and corresponds to the meaning of that construction. The same is true of the pattern, (Subj) V Obj1 Obj2, which comes to be associated with the meaning of “give,” the pattern, (Subj) V Obj Obl, which comes to be associated with the meaning of “put,” and so on. More generally, the specific formal patterns associated with particularly frequent verbs come to be associated with the meanings of those verbs. The alternative is to assume that each of these patterns and its associated meaning were known to the child at the time of the child’s first verbs. How the constructions themselves come to exist would not be explained. The value of constructions as predictors of sentence meaning If verbs in particular argument structure constructions make such excellent predictors of overall sentence meaning, as discussed in section , what drives the generalization from the verb-specific argument structure categories to the more abstract constructional categories without a fixed verb? Unlike verbs, argument structure constructions are formally very abstract; in languages like English, there is typically no overt morphological cue, and their existence can only be induced by a combination of argument types and word order facts. Again, work in the non-linguistic categorization literature provides a clue. Kruschke (1996) and Dennis and Kruschke (1998) discuss how learners shift attention away from non-distinctive cues toward distinctive cues, when learning overlapping instances that belong to distinct categories. For example if two diseases share one symptom but have their own distinctive symptom, subjects will attend more to the distinctive symptoms than the shared one.13 That is, while the verb together with its argument structure provide an extremely reliable interpretation, if the construction is a better predictor of overall sentence meaning than the morphological form of the verb, we should expect to find an increased reliance on the constructions a cue, independently of the morphological form of the verb. In fact it is clear that constructions are better predictors of overall meaning than many verbs. For example, when get appears in the VOL construction, it conveys caused motion, but when it appears in the VOO construction, it conveys transfer, and when it appears in the VL construction, it conveys intransitive motion:
get + VOL pattern “caused motion” b. Pat got bob a cake. get + VOO pattern “transfer” c. Pat got into the car. get + VL pattern “intransitive motion” Since most verbs appear in more than one construction with corresponding differences in interpretation, speakers would do well to learn to attend to the constructions. As an indication of the fact that the the construction is at least as good a predictor of overall sentence meaning as the verb, we consider again the corpus use of the VOL construction.
We reviewed all instances of the VOL construction in the database of mothers’ speech to 28 month old children in the Bates et al. (1988) corpus discussed above. Two independent coders classified utterances as either entailing caused motion or not; those that we judged not to entail caused motion were separated and further analyzed as discussed below. Disagreements were resolved through discussion. Agreement between the two independent coders was 99% initially and 100% after discussion (n = 250) for classifying mothers’ VOL utterances as entailing caused motion or not. We found that 70% (176/250) of the mother’s instances of the construction clearly entail literal caused motion. The following examples are representative:
b. bring ‘em back over here c. stuff that all in your mouth d. put ‘em in the box e. park the car over there f. pick it up here g. take ‘em in the house Another 8% of instances involve the verbs keep, have, get or leave as in the following type of examples: a. keeping these people in the garage b. does he have something on his head? c. what’s she got on? d. leave it right there The utterances in entail that the subject argument acts to keep or allow the theme argument to stay in a particular location. The subject argument is agentive and the locative phrase is predicated of the direct object argument just as in instances that entail prototypical caused motion. Many researchers have related these instances to cases of caused motion independently (e.g.,Goldberg, 1995; Matsumoto, 1992; Talmy, 1976). If we include these cases in the final tally, 78% of VOL utterances imply caused motion or caused location. Another 5% of instances involve the verbs read or say which could be argued to encode metaphorical caused motion (Ackerman & Webelhuth, 1988; Goldberg, 1995; Reddy, 1979). Including these cases would raise the total number of VOL utterances whose meanings are related to caused motion to 83%. Of the remaining VOL utterances, 20, or 8% involved locative adjuncts. We included these as instances of VOLs because we did not want to assume that the children had mastered the distinction between arguments and adjuncts. If we had excluded them, the total number of utterances included as VOL utterances would have been reduced from 250 to 230. The total percentage of VOL utterances that involved caused motion would have been 90%. “Cue validity” is the conditional probability that an object is in a particular category, given that it has a particular feature or cue (Murphy, 1982). P(A|B) is the probablity of A, given B. The cue validity of VOL as a predictor of “caused-motion” meaning, or P(“caused-motion” | VOL), is somewhere between .70 and .90, depending on how inclusive we take the notion of “caused motion” to be, and how inclusively we define the VOL formal pattern. The remaining 21 tokens include the following types of examples which do not entail literal motion:
b. What did Ivy do to her arm? (1 instance) c. find the bird in the snow (utterances with find: 2 instances) d. get Papa at the airport (move-from interpretation: 1 instance)
The verb do appears 21 times in the VOL construction. The majority of these cases (17) are instances of the special “What’s X doing Y?” (WXDY) construction. As described by Kay and Fillmore (1999), this construction is used to entail that there is something noncanonical about a situation. If we ask what the cue validity is of do as cue for this construction, we will see that it is extremely low. Do appears 551 times in the following constructions in the corpus: 21 VOL (13 in WXDY construction; 9 transitives with a locative adjunct) 5 intransitive (“act” interpretation: semantically intransitive) 159 transitive (“act on” interpretation: semantically transitive) 366 auxiliary (aspectual, polarity or grammatical meaning) The probablity of the WXDY construction, given do, or the relevant cue validity is P(WXDY | do) = 17 / 551 = .003. Thus do is, in and of itself, not a reliable predictor of overall sentence meaning when it appears in the VOL frame. While get appears 12 times in the VOL construction with a caused-motion interpretation (e.g., She got the toy into the box), the same morphological form occurs in a variety of different constructions with different meanings: 53 simple transitives (possession: get a washcloth) 15 resultative (change of state: get tired) 12 VOL construction (caused motion: get those over here) 9 transitive resultative (caused change state: get them undone) 8 VL construction (intrans. motion: get out of the car.) 7 VOO (transfer: get me some of those) 4 VP complement (modality: you got to chew your cookie up) 1 NP VP complement (causation: get to take a bath) Table . Occurrences of get in various constructions in the Bates et al. (1988) corpus The cue validity of get as an indicator of caused motion is P (“caused motion” | get) = 12/109 = .11. Take appears 14 times in the VOL construction with a meaning of caused motion, e.g., take their chairs in the house}. However, it occurs 30 times in the simple transitive construction. Twenty six of these transitive uses did not imply motion, but instead involved simple action scenes such as take a bite/a nap/some pictures; the other four did imply caused motion. Have appears 14 times in the VOL construction, including 13 instances that entail location as in have something on his head. One instance of have in the VOL pattern was have a good time at the store. Across the speech of 15 mothers, have occurred 30 times with a VP complement conveying deontic modality as in now you have to wipe your mouth, 7 times as a perfect auxiliary, and 6 times in miscellaneous other patterns. The vast majority of instances of have (61) appeared in the simple transitive construction, conveying possession (can I have one of your apples) or action (you just had a nap). The cue validity of have as an indicator of caused location is 13/118, or .11. Thus knowing only that do, get, take or have is present is not in itself a highly reliable predictor of the overall sentence meaning. The verbs put, do, get, take and have accounted collectively for 64% of the VOL tokens. To estimate the overall cue validity of verbs in the VOL construction, let us make the generous, if implausible, assumption that every single one of the remaining 36% of tokens involved a verb that was a perfect predictor of overall sentence meaning (cue validity = 1). We can then calculate the cue validity for verbs as the weighted average of the cue validity of each verb or:
Given our dubious assumption that each of the unanalyzed remaining verbs had cue validity of 1, it is clear the cue validity of .79 for the verb predicting overall sentence meaning is an upper bound. If we compare the .70—.90 cue validity for the VOL pattern as a predictor of caused motion meaning, we can see the construction looks to be roughly as reliable or valid a cue. To better compare the verbs and constructions as predictors of overall sentence meaning, it is worth considering an experiment designed to test just this.
Bencini & Goldberg (2000) conducted an experiment inspired by the Healy and Miller (1970) sorting experiment described above, which had been titled, “The Verb as the Main Determinant of Sentence Meaning.” In this earlier experiment, stimuli were created by crossing subject arguments with verbs, since it was assumed that the two best candidates for determining what the sentence was about were the verb and the subject argument. We aimed to compare the semantic contribution of the construction with that of the morphological form of the verb. The stimuli were sixteen sentences created by crossing four verbs with four different constructions:
Table . Stimuli for Sorting Experiment Seventeen University of Illinois undergraduate students were asked to sort these sixteen sentences, provided in random order, into four piles based on “overall sentence meaning.” Subjects were instructed that there was no right or wrong answer, that the experiment was only intended to determine how people sorted sentences according to sentence meaning. Subjects could sort equally well by verb: e.g., all instances of throw (1a-d) being put into the same pile, regardless of construction; or subjects could sort by construction: all instances of e.g., the VOO or ditransitive construction (1a, 2a, 3a, and 4a) being put into the same pile. It would of course be possible to design stimuli with a great deal of overlapping propositional content such that we could a priori predict either a verb or constructional sort. For example, the sentences Pat shot the duck and Pat shot the duck dead would very likely be grouped together on the basis of overall meaning despite the fact that the argument structure patterns are distinct. Conversely, Pat shot the elephant and Patricia stabbed a pachyderm would likely be grouped together despite the fact that no exact words were shared. The stimuli were designed to minimize such contentful overlap contributed by anything other than the lexical verb. No other lexical items in the stimuli were identical or near synonyms. The use of the sorting paradigm is a particularly stringent test to demonstrate the role of constructions. Medin et al. (1987) has shown that there is a strong, domain-independent bias towards sorting on the basis of a single dimension, even with categories that are designed to resist such one-dimensional sorts in favor of a sort based on a family resemblance structure (Rosch & Mervis, 1975). One-dimensional sorting has been found even with large numbers of dimensions (Smith, 1981), ternary values on each dimension (Anh & Medin, 1992), holistic stimuli and stimuli for which an obvious multidimensional descriptor was available (Regehr & Brooks, 1995). The stimuli presented subjects with an opportunity to sort according to a single dimension: the verb. Constructional sorts required subjects to note an abstract relational similarity that required the recognition that several grammatical functions cooccur. Thus we would expect verb sorts to have an inherent advantage over constructional sorts. Six subjects produced entirely construction sorts, seven subjects produced entirely verb sorts, and four subjects provided mixed sorts. In order to include the mixed sorts in the analysis, results were analyzed according to how many changes would be required from the subject’s sort to either a sort entirely by verb (VS) or a sort entirely by construction (CS). The average number of changes required for the sort to be entirely by the verb was 5.5; the average number of changes required for the sort to be entirely by construction was 5.7. The difference between these scores does not approach significance. That is, subjects were just as likely to sort by construction as they were to sort according to the single dimension of the morphological form of the verb. If verbs provided equally good cues to overall sentence meaning, there would be no motivation to overcome the well-documented preference for one-dimensional sorts: subjects would have no motivation to sort by construction instead of by verb. Bencini and Goldberg hypothesize that constructional sorts were able to overcome the one-dimensional sorting bias to this extent because constructions are in fact better predictors of overall sentence meaning than the morphological form of the verb. Bencini and Goldberg considered the possibility that our choice of verbs unduly influenced subjects’ sorts. It might be argued, for example, that while the verbs get and take may not contribute to overall sentence meaning as much as constructions, the semantically richer verbs slice and throw would. If this were so, we would expect to find that the latter verbs were put into the same piles in the sorts more often than the former verbs. However, an analysis of the number of separate piles that each verb was put into by the participants did not reveal any difference among the verbs either in the overall test (F < 1) nor in any of the single degree of freedom tests (all Fs < 1). This experiment was performed with adults, but the implications for language learning are clear. Insofar as constructions are at least as good predictors of overall sentence meaning than any other word in the sentence, learners would do well to learn to identify construction types, since their goal is to understand sentences. A question arises as to why constructions should perform at least as good as predictors of overall sentence meaning as verbs. The answer takes us back to the Gricean Maxim of Relevance and the fact that in context, knowing the number and type of arguments conveys a great deal about the scene being conveyed. To the extent that verbs encode rich semantic frames that can be related to a number of different basic scenes (Goldberg, 1995), the complement configuration or construction will be as good a predictor of sentence meaning as the semantically richer, but more flexible verb.
We have discussed cue validity, the probablity that an item belongs to a category, given that it has a particular feature: P(cat | feature), and we have found that when the category is taken to be overall sentence meaning, constructions have roughly equivalent cue validity compared with verbs. There is also a second relevant factor. Category validity is the probability that an item has a feature, given that the item belongs in the category: P(feature | cat). Thus category validity measures how common a feature is among members of a category. The relevant category is again, sentence meaning. Given that there are hundreds of verbs that can be used to convey caused motion, but there are only one or two argument structure constructions that are used to convey caused motion (namely the VOL pattern and the simple transitive construction as in He brought his lunch), the constructions clearly have higher category validity than the verbs. In this way the construction is available as a cue much more often than any individual verbs. All things being equal, if two cues have roughly equal validity, the higher category validity of one cue will naturally result in a greater reliance on that cue in categorization tasks (Bates & MacWhinney, 1987; Estes, 1986; Hintzman, 1986; Nosofsky, 1988). Thus constructions are better cues to sentence meaning than verbs insofar as they are as reliable (with equivalent cue validty) and much more available (having higher category validity).
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