This study investigates Japanese-speaking children’s and adults’ interpretation of sentences which contain a universal quantifier in the subject position and negation. In languages like English, sentences with multiple quantifiers (e.g., Some student read every book in the library.) or a quantifier and a logical operator (e.g., All the men didn’t go.) typically exhibit scope ambiguity. Research has long observed and discussed how prosody affects the interpretation and has argued that these ambiguous sentences become unambiguous when uttered with a specific prosody (Constant 2012, 2014; Jackendoff 1972; Jespersen 1933; Ladd 1980; Ward and Hirschberg 1985, among others). Similar observations have been made in other languages such as German (Büring 1997, 2003; Krifka 1998; Sauerland and Bott 2002), Hungarian (É. Kiss and Gyuris 2003; Jackson 2008), Greek (Baltazani 2002), Korean (Lee 2006), and Japanese (Hara 2006; Kuno 1973; Nakanishi 2008; Oshima 2008; Tomioka 2010a, 2010b). Previous studies have mainly focused on theoretical and pragmatic explanations for why certain interpretations arise during specific prosodic events. However, there has been much less experimental evidence presented regarding whether people actually make such interpretations. This paper will focus on an ambiguous construction in Japanese which involves a -wa-marked (Topic-marked) quantifier subject and negation. The experiments reported in this paper will investigate whether adult and child native speakers of Japanese are sensitive to this type of prosodic manipulation in the ambiguous sentences. Additionally, by considering the reaction time from hearing a sentence to selecting an interpretation, this paper aims to contribute to the understanding of the processing of the semantic and prosodic link in Japanese, particularly in the context of contrastive topic marking and quantifier scope.

The first language acquisition literature to look into the scopal relation between a universal quantifier (in the subject position) and negation by English-speaking children has seen two main findings. One is that children naturally have a strong bias towards the “All > Not” interpretation. But at the same time, the other important finding from the extensive research has shown that children can access the inverse, “Not > All” interpretation, when the context is manipulated to alleviate the processing load to interpret negated sentences or by semantic priming (Musolino 1998; Musolino and Lidz 2006; Viau et al. 2010, among many others).

Also, one thing to note is that almost all of the previous studies on this topic employed the method of Truth Value Judgment task (TVJT, Crain and Thornton 1998). Typically, researchers investigate whether children would accept the “Not > All” situation when hearing the stimulus sentence that is ambiguous. Although the TVJT is generally suited to investigate children’s knowledge of sentences whose interpretation is unambiguously determined by the target grammar (i.e. Truth is determined between true or false), it gives less information when we test ambiguous sentences if only one of the interpretations is presented in the story. For example, we do not know whether a participant also access the “All > Not” interpretation, just by observing them accepting the target sentence in the “Not > All” situation; we do not know whether a participant accepts both interpretations to an equal extent or has a preference over the other. If multiple possible interpretations are presented and tested, TVJT can also diagnose the ambiguity. Furthermore, a combination of experiments using different methods (such as a TVJT and a picture-selection task as in Syrett and Musolino 2013) would yield a higher resolution to its analysis. I thank an anonymous reviewer for directing me to the referenced material.

Sugawara et al. (2018) conducted an elaborated picture-selection task to revisit the issues. The experiment was aimed to investigate the effect of the prosody in potentially ambiguous English sentences with 24 adult and 32 child participants who are native speakers of English. The design involves two phases. The first phase introduces the situation (e.g., “Hey look, a bunch of apples here in this tree.”) and the second phase shows four pictures, illustrating the situations of (i) “All > Not” (None of the items VP-ed), (ii) “Not > All” (Some but not all of the items VP-ed), (iii) “All did” (All of the items VP-ed), and (iv) “irrelevant” event (See Figure 1). The position of the pictures was counter-balanced. The participants were asked to point to the picture which matches what the character said.

The results from adult participants show that they chose the “Not > All” pictures 23 % of the time under the Falling prosody condition and 72 % under the RFR prosody condition. Similarly, the children (aged from 4;4 to 6;10, M = 5;2) chose the “Not > All” pictures 30 % of the time under the Falling prosody condition and 70 % under the RFR prosody condition.

Although there were two factors in the lead-in question (“What happened?”-type question vs. “Did all…?”-type question), there was no effect of the question type.

In this experimental design, it is worth pointing out that the first phase of each trial was identical regardless of the condition. This means that the participants were not biased towards either of the interpretations from the start, unlike in a truth value judgment task, where one of the interpretations (situations) is presented to the participants. In the picture-selection design, they were asked to determine which interpretation was more suitable only after hearing the stimulus sentence. Therefore, the significant differences between the RFR prosody condition and the Falling condition can be attributed solely to the prosodic manipulation. Furthermore, since the non-chosen interpretation was presented as an option, the results can be safely said to indicate a preference for the chosen interpretation over the alternative.

Yatsushiro et al. (2019) conducted an experiment following Sugawara et al.’s (2018) design to test German sentences with the neutral prosody and the German CT prosody. They recruited 42 German-speaking children (ranged 3;6 to 6;11, M = 5;2) and 20 adults. They also found that both adults and children preferred the “Not > All” interpretation under the CT prosody.

Now, let us turn to Japanese CT prosody. Hattori et al. (2006) conducted an experiment involving 22 four-to five-year-old (M = 5;5) native speakers of Japanese children to investigate the relationship between prosody and scope interpretation. They used the TVJT for their experimental setup. In a story, three animals appear for a race on Sports Day, but two end up not running the race and just one animal runs the race. At the end of the story, the puppet says the following target sentence:

Children’s task is to judge whether the puppet is right or wrong relative to the story. They had four “Not > All” stories, and for two of them the target sentences were uttered with the TT prosody while for the rest two, the sentences were uttered with the CT prosody. Since the stories support the “Not > All” interpretation, the predictions are that the sentences with the TT prosody are rejected while the sentences with the CT prosody are accepted. The results show that children rejected the sentences with the TT prosody 86.4 % of the time, and they correctly accepted the sentences with the CT prosody 65.9 % of the time. They also noted that there were five children who constantly assigned the surface “All > Not” interpretation. The overall results indicate that most of the children do access the “Not > All” interpretation with the CT prosody at the age of five.

This study is nicely designed but is not free from limitations. First, they did not test an adult control group. They mentioned that Nakanishi (2008) tested the TT and CT sentences with adults to confirm the prosodic effect. However, there were only four informants, and it seems that only one pair of sentences were tested (Minna-wa ne-nakat-ta. ‘Everyone did not sleep’ with TT and CT prosody). Indeed, Nakanishi’s informants answered that the TT prosody corresponds to the “All > Not” interpretation and the CT prosody to the “Not > All” interpretation. It is, however, worth noting that Japanese has different ways to embrace a quantifier around the subject NP, as shown in the following examples. It is possible that different structures yield different results in adults, and thus it is important to set up a baseline by conducting an adult control experiment with a larger sample size.

Secondly, in Hattori et al.’s experiment, all the four stories supported the “Not > All” situation. This leads to two potential issues; (i) the results might have overestimate children’s competence, and (ii) we cannot know if children give ambiguous interpretation to the CT prosody (i.e. allowing both “Not > All” and “All > Not” interpretations) or have preference towards the “Not > All” interpretation. Having only the “Not > All” stories means that one just has to answer “yes” to be regarded as correct under the CT prosody. There was no trial included where children had to reject the “All > Not” situation to be regarded as correct under the CT prosody.

Logically, the meaning of “Not > All” does not exclude the “All > Not” situation. However, by computing indirect scalar implicature (Chierchia 2004), people tend to access the meaning of “Not all of them VP-ed (and some did).” Therefore, it is not clear if rejecting the “All > Not” situation under the CT prosody should be really treated as “correct.” However, even given this consideration, since what CT prosody requires us to compute is to have at least one LF remaining unresolved after generating and comparing alternatives, it is theoretically expected that one will access the meaning of “Not all of them VP-ed (and some did)” with the CT prosody. That is because once accepting the “All > Not” interpretation, all the alternative LFs are resolved and thus the requirements by the CT prosody would not be satisfied.

The current study aims to follow up on Hattori et al.’s (2006) study, with the picture-selection method involving adult participants as well as children to address the raised issues.

Sugawara and Wexler (2014) tested Japanese-speaking children (N = 23, ranged 4;3 to 6;2, M = 5;3) with the TT and CT prosody in a Covered Box design. Their results showed that children predominantly accessed the “All > Not” interpretation regardless of the prosody. We speculate that the children in Sugawara & Wexler’s (2014) study did not show the sensitivity to the prosodic manipulation because (i) the test sentences were transitive (e.g., Penginsan minna-wa e-o kaka-nakat-ta-yo. (penguins everyone-top picture-acc draw-neg-past-excl) ‘All of the penguins didn’t draw pictures.’), which had introduced complication since there were two arguments rather than one, and (ii) although a Covered Box task is a version of the picture-selection task, the implementation of the task involved further complication. In a Covered Box task, one needs to think twice about what is visible, and only when they are sure that what is visible is wrong, they can open the covered picture. The design was admittedly complicated to test scope ambiguity.

The overall results suggest that both adults and children exhibited different interpretations for the TT and CT prosody, highlighting CT’s role in reducing the “All > Not” interpretation. While previous literature (both theoretical and experimental studies) has noted different behaviors in TT and CT prosody, the current experiments highlighted a significant ambiguity perceived by speakers when hearing the stimuli with the TT prosody. In languages like English and German, which inherently have flexible scope, starting with the two LFs (“All > Not” and “Not > All”) for the semantic computations under the CT prosody is straightforward. However, in Japanese, if the sentences read with the TT prosody are interpreted solely as “All > Not” and that provides the starting LF for the computations under the CT, it raises questions about how the “Not > All” LF is accessed when the computation starts. If, on the other hand, the sentences like our stimuli read with the TT prosody are ambiguous, then, two LFs can be assumed as candidates for semantic interpretation similar to English and German.

While the discussion on the scope rigidity of Japanese is beyond the scope of this paper, the current experiment points out the possibility that speakers allow flexibility to a great extent even in structures traditionally considered rigid. I would hope the current study opens up the investigation of such topics. The possible factors to affect the scope flexibility/rigidity would include word choice (e.g., minna ‘everyone’ vs. NP zenin ‘every NP’), animacy, verb types (e.g., transitive vs. intransitive), types of scope relations (e.g., involving multiple quantifiers vs. a quantifier and negation), word order (as discussed in the preparatory survey), and many other factors. Future experiments on these factors are anticipated.

Turning to our results, the difference in RT analyses between adults and children indicates that adults are quicker in computation with the CT prosody. Viewing only adult results might lead one to question if the complex computations proposed in prior studies are indeed necessary to achieve the effects of the CT prosody. There might also be speculation that the CT prosody is the default, with something special occurring in interpreting the TT prosody. However, these doubts are likely resolved when comparing with children’s results. Children’s results suggest that the TT prosody involves fewer errors and thus less processing load, indicating that CT prosody’s semantic computations add processing load, leading to more errors. On top of the practical reasons of using the TT prosody to convey neutral meanings, its ease of comprehension for children suggests that the TT prosody is indeed the default. Children process the sentences with the TT prosody with no issues, and they can make use of the effects of the CT prosody when they process the sentences with the CT prosody but it appears to take time.

Another possibility to account for the difference in RT analyses between adults and children comes from a limitation of the study.

I thank an anonymous reviewer for pointing this out.

Since the semantic and pragmatic computations for the CT in Japanese align with the proposals in languages like English and German, similar outcomes are anticipated for sentence processing involving CT in other languages. It remains to be seen whether other languages will also exhibit faster reaction times for CT, compared to their corresponding neutral prosody. As previously observed in Section 1.1, the CT prosody is not limited to sentences involving flexible scope relations. Rather, it is prevalent in everyday conversations that generate a set of alternatives. The adult-like rates and/or the speed to resolve the scope interpretations under the CT prosody may correlate with the general ability to correctly interpret conversations that include contrast. The application in this direction poses a question worth exploring.

In the current paper, new sets of data were presented that showed that both adults and children exhibit sensitivity to the prosodic manipulation in sentences with a universal quantifier and negation. To be more specific, both adults and children demonstrated the reduced prevalence of the “All > Not” interpretation under the CT prosody. Although prior research has acknowledged these variations in the TT and CT prosody, this study uniquely emphasized the substantial ambiguity speakers experience with the TT prosody in the presented stimuli. The results became clear through experiments using a picture-selection task, where participants inferred meanings from the sentences they heard. The difference in the trends in reaction times points to possible differences in cognitive processing between adults and children. For adults, the CT prosody facilitates the processing, by eliminating one of the possible LFs. However, for children, the computations involved in the CT prosody result in higher cognitive load and more time-consuming sentence processing. They can make use of the role of prosody in interpreting scope relations similarly to adults, but how effective they can use the knowledge will develop gradually. The interaction of this ability with other general cognitive abilities is a promising area for future developmental research.