The scope of children’s scope: Representation, parsing and learning

This paper reviews some developmental psycholinguistic literature on quantifier scope. I demonstrate how scope has been used as a valuable probe into children’s grammatical representations, the nature of children’s on-line understanding mechanisms, and the role that experience plays in language acquisition. First, children’s interpretations of certain scopally ambiguous sentences reveals that their syntactic representations are hierarchical, with the c-command relation playing a fundamental role in explaining interpretive biases. Second, children’s scope errors are explained by incremental parsing and interpretation mechanisms, paired with difficulty revising initial interpretations. Third, a priming manipulation reveals that children’s clauses, like those of adults, are represented with predicate-internal subjects. Finally, data on scope variation in Korean reveals that in the absence of disambiguating evidence, parameter setting is an essentially random process. Together, these discoveries reveal how the developmental psycholinguistics of scope has proved a valuable tool for probing issues of grammar, parsing and learning.


Introduction
Consider the following dialog between a mother and her son, overheard in the fall of 2008. (1) Mom: If all of us don't go to back to school night, it'll be okay because one of us will be there. Five-year-old: That doesn't make any sense. participants in the dialog interpret it in opposite ways. The mother intended her sentence to convey the meaning that "not all of us goes", whereas the child interpreted it as conequivalent to the surface form is known as the observation of isomorphism (Musolino 1998). Isomorphism has proven to be a valuable probe into the nature of children's grammatical representations, the nature of children's on-line sentence understanding mechanisms, representations are hierarchical, with the c-command relation playing a fundamental role in explaining interpretive biases; (ii) children's scope errors are explained by children's incremental parsing and interpretation mechanisms paired with their trouble revising initial interpretations; (iii) children's clauses, like those of adults, are represented with Glossa general linguistics a journal of Lidz, Jeffrey. 2018. The scope of children's scope: Representation, parsing and learning. Glossa: a journal of general linguistics 3(1): 33. 1-14, DOI: https://doi.org/10.5334/gjgl.339 predicate-internal subjects; and (iv) in the absence of disambiguating evidence, parameter setting is an essentially random process. Together, these discoveries reveal how the developmental psycholinguistics of scope has proved a valuable tool for probing issues of grammar, parsing and learning.
Section 2 demonstrates that children's scope interpretations are captured by their representation of the relative c-command of scope-bearing elements, highlighting the abstract character of children's syntactic representations. Section 3 probes the pragmatic and parsing contributions to children's scope errors. In this section we see how various extra-syntactic and psycholinguistic factors interact to cause children's errors. In section 4, we return to children's representations, demonstrating through syntactic priming that children's clauses include a predicate-internal subject position. Finally, in section 5 we examine a case where the setting of a parameter with consequences for scope takes place by a random process, due to the lack of information in ambient speech. This section highlights the independence of Universal Grammar from the selection mechanisms through which learners arrive at a particular grammar.

The syntactic character of isomorphism
Consider the ambiguous sentences below along with their potential paraphrases.
(2) Every horse didn't jump over the fence a. Every horse failed to jump over the fence. b. Not every horse jumped over the fence (3) The Smurf didn't catch two birds a. It is not the case that the Smurf caught two birds b. There are two birds that the Smurf didn't catch In each case, two scope readings are possible, indicated by the paraphrases. In (2), when paraphrased as (2a), equivalent to "none of the horses jumped over the fence." This reading is called an isomorphic scope of negation. This is called a non-isomorphic interpretation since in this case surface syntactic c-command domain and semantic scope do not coincide. Similarly, (3) also exhibits an isomorphic interpretation (3a) as well as a nonisomorphic interpretation (3b).
Value Judgment Task (TVJT), preschoolers, unlike adults, display a strong preference for the isomorphic interpretation of sentences like (2-3) (Musolino 1998;Musolino et al. 2000;Lidz and Musolino 2002;Musolino and Gualmini 2004;Noveck et al. 2007, among others). Even in contexts that make the non-isomorphic reading true, children nonetheless display a bias to interpret the relevant sentences under the isomorphic interpretation. An early question concerning isomorphism was whether it should be described in terms of linear order or hierarchical structure (Lidz and Musolino 2002). Because in English, the subject both precedes and c-commands negation, when the subject is interpreted outside the scope of negation, one might describe this in terms of the precedence relation or follows and is c-commanded by negation; so, children's restriction to wide scope negation in that context could be seen equivalently as a preference for scope that matches the linear order or as a preference for scope that matches the hierarchical structure. That is, we might paraphrase "children showed a preference for the isomorphic interpretation" as Lidz: The scope of children's scope Art. 33, page 3 of 14 "children showed a preference in which the linear precedence relations among the quan-ity, it is important to ask which is correct. It is important to note, however, that this a weak question. It does not ask whether c-command or linear order is responsible for the In order to address this question, Lidz and Musolino (2002) examined parallel sena good testing ground for this question because in that language, unlike English, linear order and hierarchical structure can be easily deconfounded. For example, in (4) the (4) Kannada vidyaarthi eraDu pustaka ooD-al-illa. student two book read--'The student didn't read two books.' Hence, if isomorphism were structurally driven, we would expect wide scope for negation. If it were based on linear order, we would expect wide scope for the object.
wide scope to negation. This is shown in Figure 1 (adapted from Lidz and Musolino 2002), which plots the proportion of "true" responses in a truth value judgment task as a function of context and language. The condition labeled "not>two" makes the narrow scope labeled "two>not", the truth values are reversed. Children in both languages accepted the sentence only in the not>two condition.
The fact that children in both languages assigned the same scope suggests that the sion that the two languages are alike.
Building on this observation, Lidz and Musolino (2006) also examined numerally quan-(5) a. eraDu chitte paTNa-kke hoog-al-illa.  This is important because the isomorphism in (4) may have been due a special property However, Lidz and Musolino found that children in both languages preferred to inter-its semantics.
vides a novel kind of evidence for the hierarchical nature of children's syntactic representations. Even when children make errors, these errors are nonetheless best understood as This conclusion, however, still leaves open the question of what factors give rise to isomorphism to begin with. As we will see in the next section, understanding the causes of isomorphism allows us to gain insight into the nature of children's on-line sentence understanding mechanisms.

Isomorphism, pragmatics and the parser
In order to account for the observation of isomorphism -as it pertains to universally alent of a sentence like (2) allows only an isomorphic, i.e. 'none' interpretation. They having to retract from a more permissive grammar (Berwick 1985; Wexler and Manzini ers, this would be the correct grammar, but English learners at this stage must ultimately move to a more general grammar on the basis of experience. grammar and not to other factors having to do with the mechanics of on-line understanding and ambiguity resolution. Indeed, Musolino and Lidz (2006) showed that English-learning 5-year-olds do not have a hard-and-fast ban against nonisomorphic interpretations. When tially weakened.

(6)
Every horse jumped over the log but every horse didn't jump over the fence.
Viau, Lidz and Musolino (2010), building on Gualmini (2008) and Gualmini et al. (2008), argued that this weakening of isomorphism arose not from the form of (6), but rather to the pragmatic conditions licensing the use of negation. In particular, they argued that negative sentences are typically used to negate expectations that are established in the the negation of which is the non-isomorphic interpretation of the second conjunct. Indeed, they found that such contexts, even without an explicit contrast, reduced the amount of isomorphism exhibited by preschoolers.
cal knowledge tout court understanding and ambiguity resolution processes.
However, to say that the discourse context surrounding the use of sentences containing course contributes to ambiguity resolution and whether it is the only factor that does so. Viau, Lidz and Musolino (2010) addressed the second point by demonstrating that other that experience with nonisomorphic interpretations can lead children to access those inter-Using a priming manipulation, they showed that children who heard scopally ambiguous sentences in contexts that were highly supportive of the nonisomorphic interpretation accessed those interpretations more than those who did not. Moreover, they showed that children were able to carry that experience over to less supportive discourse contexts. expectation that every character would complete the event. They then heard 3 items that did not set up this expectation. The control group heard 6 items that did not set up Lidz's observation that certain discourse contexts increase children's likelihood to access experience is for subsequent items that lack the supportive discourse context. Because the second 3 items are identical in the two groups, we can see that prior access to the nonisomorphic interpretation leads to an increased ability to access that interpretation even in contexts that lack the helpful discourse features. of pragmatics. Experience with unambiguous sentences like (7), that are synonymous with the nonisomorphic interpretation of (6b), also carried over to the ambiguous cases, leading to higher rates of nonisomorphic interpretations, even when the discourse contexts for (7a-b) were identical. (7) a. Not every horse jumped over the fence. b. Every horse didn't jump over the fence.
The fact that nonisomorphic interpretations can be primed allows us to draw the conclusion that aspects of children's on-line sentence understanding and ambiguity resolution mechanisms play a key role in explaining children's bias for isomorphic interpretations. Lidz and Musolino (2002) and Musolino and Lidz (2003;2006) pursued this idea by parses (Trueswell et al. 1999). In particular, they argued that the isomorphic interpretafactors can help the revision process either by providing more salient cues that revision is necessary or by boosting the relevance of the nonisomorphic interpretation to the context, Support for this view comes from several adult studies demonstrating that children's only interpretation corresponds to adults' preferred or initial interpretation (Musolino and Lidz 2003;Conroy et al. 2008). For example, Musolino and Lidz (2003) presented sentences like (8) in contexts that were equally compatible with both interpretations. Such a context, for example had a total of three birds, only one of which was caught. Adults in these contexts explained that the sentence was true because the smurf only caught one bird, illustrating that they had accessed the isomorphic interpretation. They did not say that the sentence was true because of the two uncaught birds, which verify the context, adults relied primarily on the isomorphic interpretation. (9) Every boy didn't paint the___ When participants were asked to complete the sentence under time pressure, they gave 80% surface scope responses (completing the sentence with barn). But, without time pressure they were equally likely to say either barn (surface scope) or house (inverse scope).
as a major contributor to their bias (Trueswell et al. 1999;Conroy 2008 (2010), discussed above, further supbe overridden. By increasing the baseline likelihood of the nonisomorphic interpretation, revision away from the isomorphic interpretation becomes easier. dow not just into the hierarchical nature of our scope representations but also into the nature of on-line sentence understanding and ambiguity resolution processes in children.

Children's scope and the predicate internal subject hypothesis
In this section, we return to the question of the linguistic representations engaged by The literature on adult syntax provides several arguments that subjects are generated in syntactic hypothesis. The argument depends on the interaction between two phenomena that have been plural subjects. McCloskey (1997) argues that the ambiguity of (10a), in contrast to (10b-c) provides an (10) a. Every horse didn't jump over the fence b. c.

Scope and predicate internal subjects
The important thing to notice about these sentences is that (10a) is ambiguous but that neither (10b) nor (10c) is. (10a) can be interpreted as making a strong claim that none of the horses jumped over the fence or a weaker claim that not all of them jumped. This ambiguity concerns the scope of negation. Does the negation apply to something that includes the universal or not? If it does, then we get the weak reading that not all horses jumped. If it does not, then we get the strong reading that none of them did. 1 How does this scope ambiguity arise? The case where the subject takes scope over negaof the hierarchical structure of the sentence. But what about the reading where negation takes wide scope? We can consider two possibilities. First, it might be that the negation can take the whole sentence in its scope even if it does not occur at the left edge of the sentence. But this possibility is shown to be false by the lack of ambiguity in (10c). If negation could simply take wide scope over the entire sentence independent of its syntactic position, then we would expect (10c) to be ambiguous, contrary to fact. (10c) just cannot mean what (10b) does.
The second possibility is the predicate internal subject hypothesis: the structure of (10a) is really (11), with the struck-out copy of every horse representing the unpronounced residue of the subject-predicate relation: (11) every horse didn't [every horse] jump over the fence Given that there are two positions for [every horse] in the representation, we can interpret negation as either taking scope relative to either the higher one or the lower one.

Bare Plurals and the predicate internal subject hypothesis
Diesing (1992) argues for the predicate internal subject hypothesis on the basis of the interpretation of bare plural subjects, as in (12): Linguists are available (to argue with) This sentence is ambiguous between a generic and an existential reading of the bare plural subject. Under the generic reading, it is a general property of linguists (as a whole) that they are available. Under the existential reading, there are some linguists who are available at the moment. tic positions in German. The generic interpretation requires the subject to be outside of the verb phrase. The existential interpretation requires it to be inside the verb phrase (providing evidence for the availability of the predicate-internal position crosslinguistically). So, Diesing argues that we can capture a cross-linguistic generalization about the interpretations of bare plural subjects by positing that the same mapping between position pretation is associated with the unpronounced residue of the subject inside the predicate. This is not exactly evidence in favor of the predicate internal subject hypothesis, but this hypothesis allows us to link the German and English facts together in a way that a theory without this hypothesis would not.

Priming Scope with Bare Plurals
We are now in position to make an argument that puts three premises together to make a prediction about children's behavior. First, the nonisomorphic interpretation of univerthe existential interpretation of sentences with a bare plural subject involves a predicate internal subject position. Third, children's bias for isomorphic interpretations is due to extragrammatical factors that can be overcome through priming. Together these premises allow for the following prediction. If children can access the existential interpretation of bare plural subjects, then this interpretation could be used to prime the nonisomorphic interpretation of our universal-negative sentences. Indeed, Sneed (2007) shows that this prediction is borne out.
to access both the existential and generic interpretations for bare plurals. She presented children with stories about a zoo in which crocodiles generally could be found in the river crocodiles to the desert area. She then had children judge the truth of sentences like those in (13).
(13) a. There are crocodiles in the desert/river area b. Crocodiles are usually in the desert/river area c. Crocodiles are in the desert/river area.
In the scenario described above, the existential sentence (13a) is true of the desert area but false of the river area. Similarly, the generic sentence (13b) is true of the river area and false of the desert area. And, given the ambiguity of (13c), it is true of the river and Indeed, Sneed found that children are able to access both interpretations, as illustrated in Figure 3, which shows children's acceptance rates as a function of condition. Children in the "usually" condition accepted the sentence only when it made the generic interpretation true. Children in the "there" condition accepted the sentence only when the existential interpretation was true. And, crucially, children in the "bare plural" condition accepted the sentence in both contexts, suggesting that for children both readings are available.
The second step of Sneed's demonstration was to then use the bare plural sentences as were assigned to one of two conditions. In the existential condition, children were given 3 sentences with bare plural subjects in environments that made the existential reading true and the generic reading false, followed by 3 sentences probing for the nonisomorphic interpretation of sentences like (3). In the generic condition, children were given 3 sentences with bare plural subjects in environments that made the generic reading true and the existential reading false, followed by 3 sentences probing for the nonisomorphic dren in the existential condition showed a higher rate of nonisomorphic interpretations than children in the generic condition.
In short, children who had accessed the existential interpretation of the sentences with bare plural subjects were more likely than children who had only accessed the generic interpretation to also access the nonisomorphic interpretation of the scopally ambiguous sentences. This result suggests a common mechanism underlying these two interpretations, very plausibly the predicate internal subject position. 2 of evidence about the properties of the syntax of English, and plausibly other languages. In particular, while there was already substantial evidence in favor of the predicate internal subject hypothesis, Sneed's work provides a novel argument from the psycholinguistics of scope in favor of this syntactic hypothesis.

Children's scope and the character of syntactic learning
The study of scope in children has also allowed for an examination of the character of the learning mechanisms that engage Universal Grammar in development. At stake is the question of how Universal Grammar contributes to language acquisition. Does Universal learners to identify particular grammatical features of UG on the basis of their exposure?
monste-ka motun khwuki-lul an mek-ess-ta. Cookie Monster-every cookie-eat-'Cookie Monster didn't eat every cookie.' (short negation) In principle, such sentences could be compatible with two interpretations. If the universal takes scope over negation, then this would mean that Cookie Monster ate none of the cookies. If negation takes scope over the universal, then it would mean that Cookie Monster ate fewer than all of the cookies. The latter interpretation is compatible with Cookie Monster eating some cookies, whereas the former is not.
Han, Lidz and Musolino relate the interpretations of these sentences to theories of verb placement in the clause, but what is important here is that interpretive judgments in the -mine which interpretations of such sentences were licensed.
-pretation where the universal takes scope over negation. And roughly half allowed the interpretation where negation takes scope over the universal. This was true for both long puting interpretations; when the universal was in subject position, all speakers allowed only the interpretation where the universal takes wide scope. Finally Han, Musolino and Lidz (2016) found that speakers were consistent in their judgments across multiple testing sessions, and that they were consistent in their scope assignments for both kinds of grammar, with the variability in scope judgments following from which grammar that is.
Han et al. argue that this variability results from a sparseness of relevant evidence. Sentences like (14) are extremely rare (Gennari and MacDonald 2006), and even if they did occur frequently, their intended interpretation in context is unlikely to be transparent responsible for the target language. In this case, the absence of evidence leads learners of learners encounter, this choice has no consequences. But in the case of the relative scope To explore this possibility further, Han, Musolino and Lidz (2016) tested a group of children with their parents. They found again that roughly half of both populations allowed the universal to scope over negation. However, they found no correlation between parents and their children, consistent with the view that grammar selection in this case is not driven by the environment. allows learners to select a grammar from within that space. In most cases, the selection of an alternative will be driven by the input, and acquisition will be driven by the degree to which learners can identify evidence in favor of one grammar over another (Gibson and Sakas and Fodor 2012). In the extreme case that there is no relevant evidence, this mechanism chooses a grammar at random from the set of structures licensed by UG. 3 This result illustrates (a) the potential independence of the acquired grammar and the language of the environment and (b) the distinctness of UG and the grammar selection mechanism,

Conclusion
The study of scope in natural language has proven to be a valuable domain for exploring the nature of the syntax-semantics interface. In this paper, we have shown how the study of scope in children has allowed us to gain insight into the kinds of representations that preschool-aged children construct, and into the nature of syntactic representation more generally. By demonstrating that crosslinguistic commonalities in children's isomorphic behavior are best described in hierarchical terms, we learn that children's early syntactic representations are fundamentally continuous with adults', computing interpretation in terms of the relative c-command relations between scope bearing expressions. In addition, we observed that existential interpretations of bare plural subjects, but not generic interpretations, can prime the nonisomorphic interpretation of scopally ambiguous sentences.
structures. We argued that the relevant shared structure is the predicate internal subject position in which the subject is interpreted in these two constructions.
The study of scope in children has also allowed us to gain some insight into the mechanisms that children use to build interpretations in real time. We have seen that children's gesting that a fundamental source of children's scope limitations derives from the process of revising initial interpretations. nonisomorphic interpretations when allowing discourse features to play a facilitative role in elevating the likelihood of a dispreferred interpretation. Similarly, prior access to a nonisomorphic interpretation can play a facilitative role, even for sentences that occur in contexts that lack the discourse features that support nonisomorphic interpretations.
Finally, the study of scope in children has allowed to highlight the fact that a theory of universal grammar is not equivalent to a theory of learning, even if it is a major component of such a theory. Universal Grammar allows us to specify the class of possible syntactic representations, but a learning theory must also include a mechanism that maps strings of the language onto those structures. The input to the learner generally plays a selective role, helping learners to choose particular grammatical features from the stock this mechanism because it is a degenerate case. That is, it provides us with an example of how this mechanism operates even in the absence of data that would allow the learner to may be driven by properties entirely internal to learners.