3.2 Design

The experiment manipulated five kinds of nonveridical contexts as licensing conditions for shenme, to examine the range of children’s knowledge of the licensing of the NPI. These contexts are (i) negative contexts introduced by sentential negation, (ii) conditional clauses, (iii) epistemic uncertainty contexts introduced by modal adverbs such as keneng ‘probably’, (iv) polar questions, and (v) wh-questions. To investigate whether children are aware of shenme’s distributional constraint that it cannot survive in veridical contexts, the experiment also included an unlicensed test condition by placing shenme in the perfect tense.

Each of the above-mentioned (un)licensed condition contained four items. This led to 24 test stimuli in total. Additionally, to neutralise the effect that every test stimulus involved the same word shenme, 18 fillers were added, of which four contained a word order error caused by a post-positioned restriction of the universal quantifier dou ‘all’.⁴ An overview of the current experimental design is given in Appendix C. Examples of each test and filler condition are provided in Appendix D.

As mentioned earlier, all test and filler stimuli were controlled for the same length of ten words. Crucially, all the manipulated licensing structures are systematically and/or frequently attested in spontaneous speech data of Mandarin three-year-olds (see Appendix B).⁵ This means that Mandarin three-year-olds have no difficulties using various licensing structures without shenme in their spontaneous speech, which strongly suggests that Mandarin children have already acquired the manipulated licensing structures at age three, at least. This will exclude the lack of knowledge of diverse sentence structures involved in the experiment as an explanation for possible poor imitation performance. Nonetheless, one may still question to what extent participants’ imitation performance may be influenced by different structural complexities involved in different test conditions. Following Montgomery et al. (1978), I assume that structural complexity is far less important than sentence length when explaining children’s imitation performance in elicited imitation tasks.

To keep participants concentrated and interested in the experiment, visual support was employed by presenting them with a picture of familiar cartoon figures on a laptop screen before each stimulus. All stimuli were developed after selecting or designing the pictures, with the hope of ensuring that each picture supported the corresponding stimulus as much as possible. Participants first saw a picture on a laptop screen, immediately after which they heard a corresponding audio stimulus. The experiment lasted an average of fifteen minutes per participant.

3.3 Participants and procedure

A total of 88 monolingual children participated in the current experiment (2; 11 – 4; 09; M = 3; 11; SD = 0; 6; 44 girls).⁶ They were recruited via two kindergartens in the Liaoning province, which is a Mandarin-speaking area in China. The experiment was conducted individually and took place in a quiet (class)room in the kindergartens.

Two experimenters were present during the experiment. One experimenter first invited the child from a class for a game. She then introduced the four figures in the experiment, and explained how the game would proceed and what the child was expected to do. Each child was presented with four trials to get familiar with both the experimenter and the experiment. When the child proved to be able to understand what was expected of it after the trials, the experiment started. The other experimenter recorded the responses and filled in answer sheets.

3.4 Data categorisation and scoring

Responses to the stimuli were divided into two main categories: imitation and non-imitation. In principle, imitation responses refer to instances in which the participants repeated the manipulated stimuli. However, since the length of the stimuli was designed so that the participants needed to first establish their own mental representations of the stimuli, it was hardly ever the case that they were able to repeat every word unit in a stimulus. Therefore, responses were considered imitation responses when participants produced a manipulated shenme noun phrase (e.g. shenme dangao ‘a cake’ or shenme wanju ‘a toy’), in a manipulated licensing condition (e.g. in polar questions).

Based on these criteria, both (12b) and (12c) were categorised as instances of imitation of the stimulus (12a). Although both (12b) and (12c) did not contain all lexical units employed in the stimulus, both responses do contain the manipulated shenme noun phrase (namely shenme gushi shu ‘a storybook’) in the manipulated licensing condition, which is an epistemic uncertainty context, introduced by the modal adverb keneng ‘probably’.

Other responses were regarded as non-imitation. If the participants did not give a response at all, or provided an irrelevant response such as Mei ting jian ‘(I’ve) not heard (the stimulus)’ or Bu zhidao ‘(I’ve) no idea’, an instance of non-imitation was counted. If the participants reconstructed a stimulus and gave an own version of it, by replacing the manipulated shenme noun phrase by its bare or plain counterpart, for example, an instance of non-imitation was counted as well. This is illustrated in (13) as response to (12a).⁷

To be able to perform logistic regression analyses, each imitation response was assigned a value of 1, and each non-imitation response was assigned a value of 0. More on the regression models will be reported in the next section.

5.1 Shenme is a mere wh-quantifier before 2; 11

Mandarin children acquire the knowledge underlying shenme’s occurrence in wh-interrogatives as early as age 2; 11. Following the previous corpus investigation by Lin Jing et al. (2014), I assume that before this age, children analyse shenme as a wh-quantifier. Since the data presented in Section 4 suggest that children start developing their knowledge underlying shenme’s occurrence in non-wh nonveridical environments after age 2; 11, I moreover assume – in line with Lin Jing et al. – that children’s initial knowledge of shenme only contains the wh-analysis. The data presented in Section 4 suggest that children start developing their knowledge underlying shenme’s occurrence in non-wh nonveridical environments after age 2; 11. But where does this analysis come from?

In order to answer this question, a distribution-based learning approach is adopted, which was originally proposed for category learning in early language acquisition (Cartwright & Brent 1997; Redington et al. 1998; Mintz 2002; Mintz et al. 2002). Following this approach, I assume that children’s first attempt to analyse the superweak NPI shenme relies merely on their investigation of the distributional properties of input data they received and processed thus far. As reported in Lin Jing et al. (2014), shenme is attested in wh-questions in more than 97% of the input. Given its overwhelming occurrence as a question word in the input, it is far from surprising that Mandarin children initially analyse shenme as a mere wh-quantifier and do so before age 2; 11.

5.2 Shenme is a referentially deficient quantifier after 4; 06

As suggested in Section 4, around age 4; 06 Mandarin children seem to have acquired the knowledge underlying shenme’s occurrence in a wider range of nonveridical environments than wh-interrogatives only. What would this knowledge consist of? Two approaches may be possible in this respect. One approach is to assume that the child’s knowledge of shenme after age 4; 06 consists of multiple analyses, which are established via distribution-based learning, as is assumed for the development of the initial knowledge of shenme. In particular, this would mean that children have a wh-analysis for shenme’s occurrence in wh-interrogatives, a “negative” analysis for its occurrence in the scope of sentential negation, a “conditional” analysis for its appearance in conditional clauses, etc. Another approach is to assume that the child’s knowledge of shenme after age 4; 06 contains just one generalising analysis (cf. Lin Jing et al. 2014), that is, shenme is a non-referential quantifier in late child Mandarin, which is restricted to the whole array of nonveridical environments, covering all those contexts mentioned above. The two possible approaches to the child’s knowledge of shenme after age 4; 06 can be represented in Figure 2.

Figure 2

Two possible approaches to shenme in late child Mandarin.

The multiple analyses approach has two advantages. First, the initial analysis of shenme as a mere wh-word is entirely maintainable. Children do not need to undergo any reanalysis process, but only add additional analyses explaining shenme’s appearance in more types of semantic contexts, such as conditional clauses or polar questions. Second, the multiple analyses approach does not require Mandarin children to acquire the semantic knowledge of (non)veridicality, or shenme’s referential deficiency. What children need to acquire merely involves superficial occurrences of shenme in a variety of semantic configurations. They do not have to detect the common semantic property underlying the different licensing conditions for shenme; nor do they have to unravel the reason why shenme is subject to limited distribution in certain but not all semantic environments.

But this approach is confronted with two challenges. First, how can new, specific analyses be established? In the child-directed speech, shenme is attested in conditional clauses or polar questions only 0.3% of the time, and 0.4% of the time in epistemic uncertainty contexts.⁸ Given the extremely small amounts of input containing shenme licensed in various semantic configurations that are not wh-questions, it is questionable that Mandarin children receive sufficient input to be able to establish the corresponding analysis in a distribution-based learning model.

A second problem concerns generalisability. As the multiple analyses approach basically assumes that the child’s knowledge of shenme after age 4; 06 contains specific analyses, each of which only explains shenme’s occurrence in one particular type of nonveridical context, it would be a coincidence to observe a distributional pattern of the NPI in all kinds of nonveridical environments in adult Mandarin Chinese (cf. Xie Zhi-Guo 2007; Lin Jing et al. 2014; see also Section 2). Moreover, this approach does not entail that all speakers acquire the full set of possible licensing conditions for shenme, and the distributional patterns of the NPI by individual speakers are expected to influence acquisition. Since the child is assumed to establish each specific analysis based on input evidence only (e.g. if a child does not hear shenme in conditional clauses, he or she will not establish the corresponding analysis), and does not require any insight into the underlying semantic property of the corresponding context, the multiple analyses approach predicts the acquisition of shenme to be successive, individually distinct, and dependant on the distribution in the input. This implies the existence of variation among adult Mandarin speakers with respect to the set of possible licensing conditions for shenme.

However, this does not seem to challenge the single analysis approach. In this approach, shenme is treated as a non-referential quantifier in late child Mandarin. This non-referential analysis generates a distribution of superweak NPIs restricted to nonveridical contexts only, as is observed in adult language use (see again Section 2). The single analysis approach hypothesised as such relates shenme’s limited distribution in nonveridical environments to its non-referentiality, and therefore does not easily allow individual variation. In this scenario, the fact that shenme is restricted to a unified set of nonveridical contexts in adult Mandarin is not attributed to coincidence either. Therefore, I adopt the single analysis approach because of its generalisability. Under this approach, shenme is analysed as a referentially deficient quantifier. But how do Mandarin children develop this non-referential analysis of shenme from their initial assumption that shenme is a mere wh-quantifier? What is the contribution of language input, children’s nonveridical vocabulary, etc., in this respect?

5.3 Between 2; 11 and 4; 06: From a wh- to a referentially deficient quantifier

The development of children’s knowledge of shenme as hypothesised above can be schematically presented in Figure 3. Before age 2; 11 children initially analyse shenme as a mere wh-quantifier, whereas after age 4; 06 they reanalyse shenme as a referentially deficient quantifier. This subsection will explore a possible reanalysis pathway, which may give rise to the establishment of the non-referential analysis of shenme around age 4; 06.

Figure 3

Development of Mandarin children’s knowledge of shenme.

As discussed above, children’s initial assumption of shenme as a mere wh-word is triggered by the overwhelming occurrence of the NPI in wh-questions in the input, i.e. more than 97% of the time (see also Appendix A). Let us assume that when a child utters or hears shenme in a wh-question, he or she has the same semantic analysis of the question quantifier involved as their parents. Otherwise, how could the communication between parents and children proceed or be successful? Thus, when a child asks Mama chi le shenme shuiguo ne? ‘What kind of fruit did mama eat?’, for example, he or she is assumed to analyse shenme as containing a dependent variable. This means that the child has acquired the knowledge that shenme cannot be assigned a fixed value in the discourse, unlike free variables (Giannakidou 2011; Giannakidou & Quer 2013); instead, it introduces a set of possible edible things that the mother has probably eaten (cf. Hamblin 1973). This means that once children have established the wh-analysis of shenme, they also have access to the knowledge that shenme contains a dependent variable, and hence is referentially deficient.

In fact, the presence of a dependent variable not only generates a distribution of shenme in wh-questions; it also gives rise to its distribution in all kinds of nonveridical environments, e.g. the complement clause of non-factive verbs, polar questions, and conditional clauses. This is because nonveridical contexts (both wh- and non-wh ones) do not necessarily require the existence of a discourse referent, and hence sanction a lexical item that contains a dependent variable (cf. Giannakidou 2011; see also Section 2). The awareness of the presence of a dependent variable in shenme then becomes a sufficient condition for children to extend shenme’s distribution to the whole array of nonveridical environments. Thus, it is possible that children come up with an updated assumption that shenme is subject to a distributional pattern in all kinds of nonveridical contexts – including wh-interrogatives – due to its non-referentiality. This assumption, however, requires support from the language input.

As reported earlier (see also Appendix A), more than 97% of the input contains shenme’s occurrence in wh-interrogatives, and in the remaining input data shenme is attested in a number of non-wh nonveridical contexts, such as epistemic uncertainty contexts (0.3%), imperfectives (0.3%), polar questions (0.4%), etc. Although the input in which shenme appears in non-wh nonveridical contexts amounts to only 2.3%, it does support the assumption that shenme is subject to a distributional pattern in various nonveridical contexts (and thus not merely in wh-questions) due to the presence of a dependent variable. This leads children to reanalyse shenme as a referentially deficient quantifier, which is restricted by nonveridicality.

What is hypothesised above provides a possible explanation of how Mandarin children reach this generalisation, by means of reanalysis from their initial narrow assumption that shenme is a mere wh-word. In the reanalysis process as sketched above, language input seems to play an important role. Moreover, two kinds of semantic knowledge appear to be crucial as well.

First, before establishing the non-referential reanalysis, children are required to have acquired the knowledge hat shenme contains a dependent variable that cannot introduce a discourse referent. Without the acquisition of the presence of a dependent variable in shenme, children would not be able to come to the assumption that shenme may be subject to a distributional pattern in the whole array of nonveridical environments, as only dependent variables can be restricted by nonveridicality due to non-referentiality (cf. Section 2). As assumed above, children seem to have acquired the knowledge of the presence of a dependent variable in shenme when they are able to exchange wh-questions containing shenme with, for instance, their parents; but this requires further investigation.

Second, children need to have acquired nonveridicality before they can obtain any insight into the interplay between nonveridicality and non-referentiality to establish the reanalysis of shenme. However, little research has been reported on the acquisition of (non)veridicality. Nonetheless, given that nonveridicality is defined in relation to a set of worlds epistemically accessible to the speaker (cf. Giannakidou 2011; see also Giannakidou & Quer 2013), it can be assumed that nonveridicality represents the possibility of talking about different possible worlds, including the actual one. Thus, the development of Theory of Mind (ToM) may be argued to be relevant to children’s knowledge on (non)veridicality. There is evidence, for instance, for the acquisition of the basis of ToM as early as age three, such as the difference between know (veridical knowledge) and plan (nonveridical intension), as well as the difference between explanation for veridical past and prediction for nonveridical future (Wellman & Estes 1986; Wellman & Woolley 1990; Leekam 1993; among others). Such findings from the development of ToM suggest that three-year-olds may already be able to distinguish nonveridical contexts from veridical ones, as they know that only nonveridical contexts do not entail the truth of an embedded proposition. The acquisition of (non)veridicality goes beyond the scope of this paper, and is therefore left for future exploration.

The hypothesised reanalysis process indicates that Mandarin children acquire the superweak NPI shenme via a wh-analysis. The transition from a wh-quantifier to a referentially deficient quantifier in acquisition is in line with Giannakidou’s treatment of superweak NPIs (1998; 2002; 2010; 2011), which explains NPI-hood by referential deficiency – a consequence of the presence of a dependent variable. The reanalysis process of shenme can therefore be considered a modifying process that is based on input evidence within the same category of lexical deficient quantifiers, in particular, from wh- to non-referential quantifiers.

5.4 Poor imitation performance with epistemic uncertainty stimuli after 4; 06

As discussed above, after age 4; 06, Mandarin children have developed the non-referential analysis of shenme, which generalises its appearance to various nonveridical environments, including wh-questions. The question now arises as to why the reanalysis does not allow the older participants (i.e. those above age 4; 06; N = 9) to repeat shenme in epistemic uncertainty contexts – a kind of nonveridical context – as often as in the other non-wh nonveridical contexts manipulated in the experiment (see again Section 4). Before presenting possible explanations for the older children’s poor imitation performance with the epistemic uncertainty stimuli, let us first look at what these older participants do when they do not give an imitation response to the epistemic uncertainty stimuli. An overview of relevant data is presented in Table 3.

The frequency data presented in Table 3 show that the older participants, when they do not give imitation responses, mainly employ two kinds of strategies to reconstruct the manipulated stimuli containing shenme appearing in epistemic uncertainty contexts. These strategies are: changing the aspect of the stimuli from past perfect to progressive (47.6% of the time; 10 out of 21), or changing the stimuli into wh-questions by, for instance, adding a Q-marker (33.3% of the time; 7 out of 21). An example of the epistemic uncertainty stimuli is given in (14); and examples of children’s responses to stimuli such as (14), in which these two strategies are employed, are given in (15a) and (15b), respectively.

The two types of reconstruction strategies suggest that the participants’ knowledge of shenme at older ages does not seem to allow it in the scope of epistemic modal adverbs such as haoxiang ‘probably’, or keneng ‘possibly’. The most straightforward way to understand this is to assume that the older participants have not yet acquired the lexical knowledge required in the corresponding test conditions. If they do not know how to linguistically express epistemic uncertainty, namely if they have not yet acquired how to say e.g. probably in Mandarin Chinese, it logically follows that they would not be able to repeat the stimuli containing shenme licenced by such epistemic modal operators. As mentioned in Subsection 3.2 (see also Appendix B), however, Mandarin three-year-olds are already able to use epistemic modal adverbs frequently and systematically in their spontaneous speech. Thus, the vocabulary-based explanation does not seem to be on the right track.

Another possible explanation is that the experiment contained a discrepancy between the manipulated stimuli and the corresponding visual support in terms of epistemic (un)certainty. Take again (14) as an example. Before hearing this stimulus, which conveys an epistemic uncertainty activity, the participants were presented a picture on a laptop screen in which Tiger and Winnie the Pooh are reading a storybook, which visually represents a factual event. Thus, the visual support did not in fact support the epistemic uncertainty stimuli.⁹ This may have resulted in the older participants’ poor imitation performance in the relevant test condition.¹⁰

5.5 Unable to detect shenme’s distributional constraint?

Finally, let us look at the older participants’ imitation performance when confronted with shenme in the perfect tense. The question that arose from the interpretation of the regression results (i.e. in Section 4) is whether the participants are unable to detect the distributional constraint of shenme. Not being able to detect this constraint would account for the increase in imitation probabilities in the perfect tense condition predicted for the older participants. By discussing the production data obtained from the four-year-olds, I will argue in this subsection that their imitation performance in the perfect tense condition should be explained as a consequence of their increased working memory capacity.

As mentioned in Subsection 3.1, the choice of the same stimuli length for all participants, independent of their ages, may result in better imitation performance by the older participants – under the assumption that children’s working memory increases with their age. Yet, the current experiment did not contain an objective measurement of the participants’ working memory capacity. This makes it difficult to examine to what extent this capacity may have influenced their imitation performance. However, when looking at the production data from the four-year-olds (N = 45), there seems to be indirect evidence that there is an effect of expanding working memory capacity. It concerns an asymmetry between the (un)grammaticality of these participants’ responses to the grammatical and the ungrammatical stimuli. The relevant data are given in Table 4.

When the four-year-olds are confronted with the ungrammatical stimuli containing shenme in the perfect tense, two response types are most frequent. On the one hand, ungrammatical responses (36.1%; 65 out of 180) signal imitation performance on the ungrammatical stimuli. On the other, grammatical responses, in which children correct the ungrammatical stimuli (57.2%; 103 out of 180), signal underlying knowledge of shenme’s possible contexts. This pattern differs strongly from what we can observe with grammatical stimuli: in response to grammatical utterances, children almost always give grammatical responses (94.9%; 854 out of 900). This significant asymmetry leads to the generalisation that the children only overuse shenme in non-licensing conditions if the stimuli are themselves ungrammatical (χ² (3, N = 1080) = 256.308, p = .000). This asymmetry suggests that shenme’s appearance in veridical contexts such as the perfect tense is not in agreement with the older participants’ knowledge of shenme; otherwise, they would also systematically produce shenme in non-licensing environments in their responses to the grammatical stimuli. This excludes the possibility that Mandarin children are unable to detect shenme’s distributional constraint.

Further evidence for the ungrammaticality of shenme appearing in the perfect tense in late child Mandarin involves the strategies that the four-year-olds employ to correct ungrammatical stimuli. Among the 103 non-imitation responses to the ungrammatical stimuli (namely the grammatical responses to the stimuli in the unlicensed test condition in Table 4), three main correction strategies are distinguished: substituting shenme by its bare or plain counterpart (i.e. 72.8%; 75 out of 103), changing the ungrammatical stimuli into an epistemic uncertainty context by adding a modal adverb like haoxiang ‘probably’ (i.e. 8.7%; 9 out of 103), and transforming the ungrammatical stimuli into a wh-question, for instance by adding a Q-marker (i.e. 10.7%; 11 out of 103). These strategies demonstrate that the four-year-olds are aware of shenme’s distributional constraint, since they either remove shenme from perfect tenses or make the veridical contexts nonveridical.

It is important to note that the CHILDES data reported in Lin Jing et al. (2014; see also Section 2) already reveal that monolingual Mandarin children do not overgeneralise shenme to veridical contexts in their spontaneous speech. The two kinds of production data – obtained from both experimental and corpus research – converge: they both show that children are able to acquire the restricted distribution of shenme in the target language.

The explanation based on working memory capacity, however, gives rise to a crucial question for understanding the significant improvement in the participants’ imitation performance in the four non-wh test conditions. To what extent does it represent a development in the participants’ underlying knowledge of shenme, rather than merely reflecting their increased working memory capacity? Here, I adopt Eisenbeiss (2010) and argue that, although working memory capacity is one of the factors that can affect children’s performance in an elicited imitation task, it cannot explain the differences between different test conditions observed for the same participants. The effects of working memory should be similar for the same participant, independent of test conditions. This means that, if only working memory is at play in participants’ imitation performance, no significant differences should be found across different test conditions. However, results of a repeated measure ANOVA confirm that this is not the case, as a significant within-subject effect is attested for the four-year-olds (F(5, 1074) = 47.882, p = .000). Thus, working memory is not the only factor that underlies the participants’ good imitation performance in different test conditions at older ages.