1.2.1 The multiplicity inference

The multiplicity inference of plural morphology on count nouns is the source of a long-standing puzzle.⁵ We illustrate the pattern below using examples from Greek.⁶ Consider the sentence in (8), containing the pluralised count noun ghurunia ‘pigs’.

The sentence in (8) sounds roughly equivalent in meaning to one in which the plural marker is replaced by ‘more than one’, as in (9).

This fact suggests that plural morphology should be associated with an exclusive ‘more than one’ meaning; in other words, the literal meaning of (8) could be paraphrased as (9) (Link 1983; Lasersohn 1995; Chierchia 1998). The problem with this hypothesis arises when we consider the negative counterpart of (8), provided in (10a). Given the hypothesis above, we would expect (10a) to have a meaning that corresponds to the negation of (8), as in (10b). Instead, the sentence’s meaning is the negation of the corresponding sentence with the singular noun in (10c).

This pattern is not restricted to negation. The absence of the expected ‘more than one’ meaning of the plural noun is also observed in other downward-entailing environments. For example, while one can deduce from (11) that we should thank the tiger even if she fed only one pig, one cannot make such an inference from (12). Similarly, if the tiger fed only one pig, the interlocutor can respond affirmatively to the question in (13) but not to the question in (14).⁷

The pattern above can be summarised as follows: the interpretation of positive sentences with plural morphology includes a ‘more than one’ inference, but this multiplicity inference disappears under negation, in the antecedent of conditionals, and in questions. This pattern is clearly problematic for a simple semantic account of multiplicity inferences, which encodes the inference in the literal meaning of plural morphology; such an approach would wrongly predict weaker meanings than are observed for cases like (10a), (11), and (13).

1.2.2 The abundance inference

Interestingly the same pattern arises in the case of the abundance inference of pluralised mass nouns in Greek. To illustrate, consider the sentences in (15) and (16), containing the pluralised mass noun zahares ‘sugars’. Analogously to the case of plural count nouns, the observation is that (15) seems equivalent to (16), suggesting that the plural morphology on mass nouns should be associated with an exclusive ‘a lot of’ meaning.

Again, the problem with the hypothesis that the literal meaning of (15) can be paraphrased as in (16) arises in downward-entailing environments. Crucially, (17) does not suggest that the zebra didn’t drop a lot of sugar, but rather that she didn’t drop any sugar at all, which is unexpected if ‘a lot of’ is a part of the literal meaning of the plural noun.

As discussed in Kane et al. (2015), the same holds for conditionals and questions: if the zebra dropped only a little sugar, we should tell her mother in the case of (18) but not in the case of (19). Correspondingly, if the zebra dropped only a little sugar we should respond affirmatively to (20) but not to (21).

As in the case of the multiplicity inference, the presence of the abundance inference in upward-entailing contexts and its disappearance in downward-entailing ones is problematic for an analysis of the abundance inference as simply part of the lexical meaning of plural morphology on mass nouns, as proposed for instance in Alexiadou (2011). Rather, it suggests that we should seek a unified account that captures the pattern of the multiplicity and abundance inferences in upward- and downward-entailing contexts in a uniform fashion.

There are two main competing approaches in the literature that aim to account for the described pattern with respect to multiplicity inferences: the ambiguity approach (Farkas & de Swart 2010, see also Grimm 2013 and Martí 2017) and the implicature approach (Sauerland 2003; Spector 2007; Mayr 2015, among others).⁸ As discussed in Tieu et al. (2018), while both approaches can account for the upward- versus downward-entailing pattern of multiplicity inferences, they differ in what they predict with respect to the acquisition of these inferences and their relationship with scalar implicatures. Tieu et al. (2014; 2018) tested the predictions of the two approaches for multiplicity inferences in English, and report evidence for the implicature approach to multiplicity inferences.

In the following sections, we first show how the ambiguity approach and the implicature approach to the multiplicity inference of pluralised count nouns can be extended to account for the abundance inference of pluralised mass nouns. We then further test the predictions of the two approaches for multiplicity and abundance inferences in Greek, extending the previous experimental studies by Tieu et al. (2014; 2018). In particular, we compare adults’ and preschool-aged children’s performance on abundance inferences, multiplicity inferences, and the ‘not all’ implicature of merika ‘some’ illustrated in (22), which suggests that the lion didn’t carry all of the apples.⁹

As we will discuss, our results replicate the patterns reported in Tieu et al. (2014; 2018) for multiplicity inferences, crucially revealing an analogous pattern for abundance inferences. The findings provide further support for an implicature approach to the multiplicity inference and an extension of the approach to abundance inferences. In addition, we show how investigating a language like Greek, which allows the pluralisation of mass nouns, provides an empirical basis for a unified analysis of plural marking across the mass-count divide.

The rest of the paper is organised as follows. In the next section, we sketch the ambiguity and the implicature approach to multiplicity inferences and we show how they can be extended to account for abundance inferences. We also discuss the predictions of the two approaches in relation to adults’ and children’s behaviour. In Section 3, we summarise the previous studies by Tieu et al. (2014; 2018), which tested the predictions of the two accounts for the multiplicity inference; we show how their paradigm can be extended to a novel investigation of the abundance inference. In Section 4, we present our experiment comparing the two inferences in children and adults, and in Section 5 we discuss the results in the context of the predictions of the two approaches. We conclude the paper in Section 6.

2.1.1 The multiplicity inference

In order to account for the observation that multiplicity inferences appear in upward-entailing contexts but disappear in downward-entailing contexts, Farkas & de Swart (2010) (see also Grimm 2013; Mathieu 2014; Martí 2017) propose a more enriched semantic account than the one mentioned above. Simplifying somewhat, their approach is based on two main ingredients: a polysemous meaning for plural morphology and a principle for choosing between these meanings in different contexts.¹⁰ In other words, they argue that a sentence like (8), repeated below in (23), is ambiguous between two meanings, which can be paraphrased as in (23a) and (23b). Correspondingly, (10a), repeated in (24), is associated with the two meanings paraphrased in (24a) and (24b), where ‘strong’ and ‘weak’ refer to entailment patterns (the strong meaning asymmetrically entails the weak one).

However, the proposed ambiguity alone will not account for the fact that in upward-entailing contexts, the plural tends to be interpreted exclusively, as in (23b), while in downward-entailing contexts it tends to be interpreted inclusively, as in (24a). In order to account for this pattern, Farkas & de Swart (2010) assume a version of the Strongest Meaning Hypothesis, formulated as in (25), which essentially regulates the choice between the two possible meanings in favour of the strongest of the two (see Dalrymple et al. 1998; Winter 2001, among others).

The Strongest Meaning Hypothesis favours the exclusive interpretation of plurals in upward-entailing contexts; that is, it favours the stronger (23b), according to which the tiger fed more than one pig, over the weaker (23a), according to which the tiger fed one or more pigs. Conversely, the inclusive interpretation is preferred in downward-entailing contexts, since in these contexts it gives rise to the stronger reading; that is, the stronger (24a), according to which the tiger didn’t feed one or more pigs, is preferred over the weaker (24b), according to which the tiger didn’t feed more than one pig. The combination of the proposed ambiguity with the Strongest Meaning Hypothesis therefore allows Farkas & de Swart’s (2010) approach to account for the sensitivity to monotonicity exhibited by the multiplicity inference.

In addition, note that the Strongest Meaning Hypothesis as formulated in (25) does allow for the possibility of weak interpretations, in cases where the strong meanings are in conflict with the context of utterance. We therefore expect to be able to force a weak interpretation through a continuation that is in conflict with the strong interpretation. This is indeed the case, as illustrated in (26):

2.1.2 Extension to the abundance inference

The ambiguity approach can be readily extended to the abundance inference. In the domain of pluralised mass nouns, a sentence like (27), repeated from above, is associated with the two meanings in (27a) and (27b). In the same way, the negative counterpart in (17), repeated below in (28), is associated with the two meanings in (28a) and (28b).

In the same way as above, the Strongest Meaning Hypothesis in (25) regulates the choice between the two possible meanings, favouring the strongest between the two. In upward-entailing contexts, that corresponds to the exclusive interpretation in (27b), according to which the zebra dropped a lot of sugar, and in downward-entailing contexts, that corresponds to the inclusive interpretation in (28a), according to which the zebra didn’t drop a little or more than a little sugar. In addition, as in the case of count nouns, the strong interpretation of the plural is blocked if it is in conflict with the continuation of the sentence, as illustrated in (29):

In sum, the ambiguity approach can explain the different readings of the plural and their distribution across the mass and count domains in both upward- and downward-entailing contexts. In the next subsection, we turn to a different take on the puzzle, which involves treating multiplicity and abundance inferences as implicatures.

2.2.1 The multiplicity inference

A different response to the pattern associated with the multiplicity inference is to treat it as a type of implicature. This approach is based on the observation that (scalar) implicatures, just like multiplicity inferences, arise in upward-entailing contexts but typically disappear in downward-entailing contexts. To illustrate, a familiar example of a scalar implicature is given in (30). In response to a positive sentence containing a disjunction phrase ‘A or B’, we typically infer exclusivity, such that the disjunction phrase ‘A or B’ is taken to mean ‘A or B, but not both’. Illustrating again with Greek examples, (30a) implies (30b).

However, when disjunction is embedded under negation, it is typically interpreted inclusively, rather than exclusively: (31a) is typically interpreted as (31b) and not as (31c); the latter corresponds to the negation of the exclusive meaning of disjunction and is compatible with Dimitri eating both the apple and the orange. But (31a) is not generally interpreted as being compatible with such a situation.¹¹

Thus we see that multiplicity inferences and classical scalar implicatures share the property of arising in environments that are upward-entailing and disappearing in downward-entailing ones.

The standard approach to deriving scalar implicatures like (30b) is to treat them as arising from a hearer’s reasoning about why a cooperative speaker would say what she did and not something else (see Grice 1975 and much subsequent work). Schematically, the implicature above would arise from the comparison of the original assertion with alternative assertions that could have been uttered but were not. In particular, a sentence with a weak scalar term like ‘or’ is compared to the stronger alternative sentence containing ‘and’:

Assuming the speaker is being cooperative and as informative as he or she can be, the fact that he or she uttered the assertion containing ‘or’, rather than the more informative alternative sentence containing ‘and’, invites the listener to conclude that the speaker was not in a position to assert the stronger alternative. The listener further infers that the stronger alternative must therefore be false, deriving the inference in (30b).

This reasoning also naturally explains why (31a) doesn’t give rise to an implicature and, as we observed, is instead interpreted as the negation of an inclusive disjunction. In this case, the listener will reason that the alternative sentence is (33), but (33) is not more informative than (31a); in fact it is weaker, and therefore the listener will draw no implicature from (31a).

The implicature approach to multiplicity inferences extends the reasoning above to sentences like (8) and (10a), repeated below in (34) and (35):

Roughly, the idea is that upon hearing a sentence like (34), which is assumed to unambiguously mean that the tiger fed one or more pigs, the listener will ask herself why the speaker didn’t say (something to the effect of) (36) instead.

Variants of the implicature approach differ in how they derive the alternative over which the multiplicity inference is computed and in turn how the latter is obtained. Sauerland (2003) and Sauerland et al. (2005) derive the multiplicity inference by comparing the presuppositions of the singular with that of the plural, while Zweig (2009), Ivlieva (2013), and Mayr (2015) derive it as a more standard scalar implicature, but computed locally at the level of the predicate rather than at the sentence level. Finally, Spector (2007) derives the multiplicity inference as a recursive/higher-order implicature, arising through a comparison between the plural and the singular enriched with its own implicatures. For concreteness, we adopt Spector’s (2007) version of the implicature approach to the multiplicity inference and its predictions. We briefly outline the main ingredients of this account below, but see Appendix A for further details.

As mentioned, Spector (2007) derives the multiplicity inference as a higher order implicature at the global level. The assumption is that at this level both singular and plural are equivalent to (37):

However, the singular in (38a) gives rise to its own scalar implicature: (38a) competes with the alternative in (38b), and since the latter is stronger, the hearer will end up concluding that it is false, via the scalar implicature reasoning sketched above. The falsity of (38b) and the truth of (38a) together entail the exactly one inference in (39).

It is this enriched interpretation of (38a) in (39) that competes with the corresponding plural sentence in (34). That is, given that (39) would have been more informative than (34), the listener will conclude that the speaker must believe that (39) is false. If (34) is true and (39) is false, the result is then precisely the multiplicity inference, as illustrated in (40):

In addition, in the same way as with the disjunction case above, this approach can explain why the negated sentence in (35) is not associated with a multiplicity inference. The listener will compare (35) to its alternative in (41). (41), however, is weaker than (35) and therefore the listener will not draw any implicature from (35).

Moreover, the scalar implicature approach can also account for the additional reading of the negated plural in (26) above, repeated below in (42).

This kind of reading also arises with standard scalar items like disjunction; for instance, (43), when pronounced with stress on ‘or’, also has a marked reading compatible with Dimitri eating both the apple and the orange. The implicature approach simply resorts to whatever mechanism accounts for (43) and extends it to (42). The general way of generating these marked readings involves postulating a local scalar implicature under the scope of negation (Fox & Spector 2018, among others). Scalar implicatures tend not to arise under negation so such readings are correctly predicted to be marked.

2.2.2 Extension to the abundance inference

As with the ambiguity account, the implicature approach can also be extended to the mass domain, as recently proposed by Kane et al. (2015). Extending Spector (2007) to the mass domain, Kane et al. (2015) assume that at the global level both the singular and the plural in (44) and (45), respectively, are equivalent to (46):¹²

The singular in (44), but not the plural, competes with ‘The zebra dropped a lot of sugar’. As the latter is a stronger alternative, upon hearing (44) the hearer concludes that the stronger alternative must be false. Since (44) is true and the alternative ‘The zebra dropped a lot of sugar’ is false, the hearer concludes that Zebra dropped some but not a lot of sugar, as shown in (47):¹³

The plural in (45) competes then with this enriched meaning of the singular in (47). Given that it would have been more informative than (45), the listener will conclude that the speaker must think that (47) is false. But, again, if (45) is true and (47) is false, the result is the abundance inference that arises as part of the meaning of the pluralised mass noun, as illustrated in (48):

In addition, in the same way as above, we can explain why (17), repeated below in (49), is not associated with any inference.

This is because the listener will compare (49) to its alternative in (50), which is in fact weaker than (49) and therefore the listener will not draw any implicature from (49).

As was the case for the multiplicity inference, the scalar implicature approach will also account for the marked reading of (49) in (51), repeated from above.

In sum, both the ambiguity and the implicature approach can account for the different readings associated with plural morphology across the mass and count divide, in particular for the pattern of sensitivity to monotonicity that they exhibit. In the next subsection, we turn to the different predictions they make in relation to the status of positive and negative plural sentences in certain contexts, and the comparison between (preschool-aged) children and adults on the interpretation of these sentences. These predictions motivated the previous experiments reported in Tieu et al. (2014; 2018), which investigated multiplicity inferences, as well as the present study, which extends the investigation of the predictions of both approaches to the abundance inference.

2.3.1 Adults

Sensitivity to monotonicity As discussed, both the ambiguity and the scalar implicature approach predict the pattern above regarding upward- and downward-entailing contexts, with multiplicity and abundance inferences arising in the former but less so in the latter. Under both approaches, we therefore expect to observe this pattern experimentally when we look at adults’ interpretations of the plural in such contexts.

Response patterns in positive and negative targets On the other hand, the two approaches differ with respect to the relationship between the positive and negative targets, when the multiplicity inference is not satisfied in the context, as in (52):

That is, while both approaches predict that (52a) and (52b) should mostly be rejected in the given context, the assumed source of rejection is different. On the ambiguity approach, both (52a) and (52b) are simply false in the given context. That is, (52a) is interpreted as ‘The tiger fed more than one pig’ and (52b) is interpreted as ‘The tiger didn’t feed one or more pigs’; both are false when the tiger only fed one pig. The ambiguity approach therefore predicts the same status for (52a) and (52b) in the given context.¹⁴

The implicature approach, on the other hand, predicts that (52a) and (52b) clash with the context above for different reasons: while in (52a) it is the implicature – the multiplicity inference – that is false in the context, (52b) is simply false in the context by virtue of its literal meaning. In other words, under the implicature approach, (52a) and (52b) have a different status in the given context.

Summarising, the ambiguity approach predicts no difference in the response patterns of the positive and negative targets in a context in which the multiplicity inference is not satisfied, while the implicature approach is compatible with a different response pattern for the negative and positive sentences in the same context.¹⁵

2.3.2 Children

As discussed in Tieu et al. (2018), the ambiguity and the scalar implicature approaches make different predictions for how children and adults should interpret the plural. In this respect, a comparison between 4–6-year-old children and adults is particularly useful, as much work has already been conducted on how the two groups differ in the computation of scalar implicatures. Amidst considerable variation in the reported rates at which children and adults compute implicatures, a fairly robust finding has been that children typically compute fewer implicatures than adults do (Chierchia et al. 2001; Gualmini et al. 2001; Noveck 2001; Papafragou & Musolino 2003; Foppolo et al. 2012, among many others). For example, children typically accept sentences such as (53) in situations where the stronger alternative (53a) is also true. This observation has usually been taken to indicate that children fail to compute the implicature in (53b).

Certain factors have been shown to impact children’s performance on scalar implicatures, such as, for example, making the scalar alternatives more salient in the context (for discussion of potentially relevant factors, see Papafragou & Tantalou 2004; Barner et al. 2011; Katsos & Bishop 2011; Stiller et al. 2015; Hochstein et al. 2016; Singh et al. 2016; Skordos & Papafragou 2016; Tieu et al. 2016; 2017c, among others). What matters for our purposes is that if multiplicity and abundance inferences are scalar implicatures, then we might also expect children not to compute such inferences from sentences like (54) and (55) below, or at least to do so less often than adults do.¹⁶¹⁷

While the implicature approach makes a fairly clear prediction about how children should perform on multiplicity and abundance inferences compared to adults, what the ambiguity approach predicts instead depends on whether the children being tested have already acquired the two proposed meanings of the plural, and whether they are able to comply with the Strongest Meaning Hypothesis in an adult-like fashion. In particular, under the ambiguity approach, there could be three reasons for children to display non-adult-like performance on plural sentences like the above (see discussion in Tieu et al. 2018; Tieu & Romoli 2018):

1. Children have only acquired the exclusive meaning of plurals;

2. Children have only acquired the inclusive meaning of plurals;

3. Children have acquired both meanings of the plural but have not yet mastered adult-like application of the Strongest Meaning principle.

These three potential developmental scenarios would lead to distinct patterns of behaviour from children, compared to adults. Recall that for adults, the plural is typically interpreted exclusively in upward-entailing contexts but inclusively in downward-entailing contexts. With this in mind, we can formulate the predicted patterns of behaviour arising from scenarios (a)–(c) as follows:

1. predicts that children will behave like adults in their interpretation of the plural in upward-entailing contexts but not in downward-entailing contexts.

2. makes the opposite prediction: children will behave like adults in their interpretation of the plural in downward-entailing contexts but not in upward-entailing contexts.

3. predicts that children may not be guided by the relative strength of the two meanings in their selection of the different readings across upward- and downward-entailing contexts.¹⁸¹⁹

2.3.3 Comparison among inferences

The formal theories of inferences we have outlined do not make direct predictions about processing or acquisition. They do, however, make general predictions about whether these inferences should be classified together or not. Based on this, we can make progress in our understanding of these inferences by comparing them directly, in the spirit of Chemla & Bott (2014: 394):

“Methodologically, we showed how to use processing data to inform linguistic classification enterprises. It requires both a careful examination of modern linguistic theories and a realization of their predictions at a cognitively relevant level. Unfortunately, specific cognitive implementations of formal theories are often missing or highly underspecified. By targeting comparisons between different types of inferences, however, progress can be made on the classification task without being committed to distort the formal models or post-hoc cognitive reconstructions of them.”

This approach has recently been applied to study the processing of various inferences in adults and their acquisition by young children.²⁰ Comparing inferences is relevant for our purposes because the implicature and ambiguity approaches also differ when we look specifically at the comparison between scalar implicatures on the one hand and multiplicity/abundance inferences on the other. This is because if multiplicity and abundance inferences are derived as a kind of scalar implicature, the implicature approach predicts that the behavioural pattern associated with these inferences should mirror that of other scalar implicatures. The exact nature of this uniformity prediction is in fact complicated by the fact that adults’ rates of implicature computation have been reported to vary quite widely across different lexical scales (van Tiel et al. 2014). For example, the ‘not all’ implicature of some was found to be computed much more by adults than the ‘not love’ implicature of like. Importantly, however, following Tieu et al. (2018), we argue that if we look at the comparison between the scalar implicature of some and the multiplicity and abundance inferences across different populations, keeping the context and paradigm constant, there remains an expectation of a uniform pattern, regardless of whether the three inferences differ within a single population. Based on Tieu et al. (2018), we can formulate the uniformity prediction of the implicature approach as follows:

In other words, while the implicature approach is compatible with within-population differences, it predicts a similar pattern across populations with respect to the three inferences.

The ambiguity approach, on the other hand, makes no particular predictions with respect to the relationship between standard implicatures on the one hand, and multiplicity/abundance inferences on the other. Whatever data we obtain about this relationship therefore will not constitute an argument for nor against the ambiguity approach. As we will discuss further below, however, the data from the multiplicity and abundance inferences alone will suffice to bear directly on the ambiguity approach, in particular posing a challenge for the approach.

In sum, while both the ambiguity and implicature approaches make the same prediction with respect to the pattern of multiplicity and abundance inferences in upward- vs. downward-entailing contexts, they differ in the predictions they make regarding children’s and adults’ interpretations of the plural, as well as how the plural inferences should compare with standard implicatures.²¹

In the next section, we briefly describe Tieu et al.’s (2014; 2018) studies, which tested the predictions of these approaches for the multiplicity inference in English. We then discuss how their paradigm can be adapted to multiplicity and abundance inferences in Greek.

4.2.1 Count noun condition

Figure 3 displays the percentage of 1-, 2-, and 3-strawberry responses to the positive and negative count noun targets. We fitted a mixed effects ordinal regression model to the plural data with Group (baseline: adults), Polarity (baseline: positive), and their interaction as fixed effects, and by-participant intercepts and by-participant slopes for Polarity as random effects. The model revealed significant effects of Polarity (β = –7.93, z = –5.32, p<.001) and Group (β = 4.01, z = 4.17, p<.001), and no interaction between Polarity and Group (p>.05). Overall, participants were more likely to give lower ratings to the negative target sentences, children tended to give higher rewards than adults, and this between-group difference did not vary across the polarities.

Figure 3

Count nouns: Proportion of 1-, 2-, and 3-strawberry responses to positive and negative targets.

4.2.2 Mass noun condition

Figure 4 displays the percentage of 1-, 2-, and 3-strawberry responses to the positive and negative mass noun targets. We fitted a mixed effects ordinal regression model to the plural mass noun data with Group (baseline: adults), Polarity (baseline: positive), and their interaction as fixed effects, and by-participant intercepts and by-participant slopes for Polarity as random effects. The model revealed significant effects of Polarity (β = –5.33, z = –6.43, p<.001) and Group (β = 2.02, z = 3.59, p<.001), and a significant interaction between Polarity and Group (β = –1.76, z = –1.99, p<.05). Overall, participants were more likely to give lower ratings to the negative target sentences, children tended to give higher rewards than adults, and there was less of a difference between adults and children on the negative targets compared to the positive targets.

Figure 4

Mass nouns: Proportion of 1-, 2-, and 3-strawberry responses to positive and negative targets.

4.2.3 Multiplicity vs. abundance inferences vs. scalar implicatures

We now consider the results across all the positive conditions, namely the positive multiplicity inference targets, the positive abundance inference targets, and the scalar implicature targets. Figure 5 displays the proportions of reward types given in response to these targets, across the two groups.

Figure 5

Percentage of 1-, 2-, and 3-strawberry responses across inferences and groups.

We fitted a mixed effects ordinal regression model to the positive plural and scalar implicature data, with Group (baseline: adults), Inference Type (baseline: multiplicity inferences), and their interaction as fixed effects, and random by-participant intercepts. The model revealed a significant effect of Group, with children giving higher rewards than adults (β = 3.21, z = 6.35, p<.001). The model also revealed significant effects of Inference Type, with participants giving higher rewards for the mass noun targets than for the count noun targets (β = 1.10, z = 2.62, p<.01), and lower rewards for the scalar implicature targets than for the count noun targets (β = –1.54, z = –5.39, p<.001). There were no significant interactions between Group and Inference Type when comparing count nouns to mass nouns nor when comparing count nouns to scalar implicatures (both p>.05). In sum, children tended to give higher rewards than adults overall, participants computed fewer abundance inferences than multiplicity inferences, participants computed more scalar implicatures than multiplicity inferences, and the difference between children and adults did not vary significantly across the count noun and mass noun conditions nor across the count noun and scalar implicature conditions.

Summarising, while the inferences were not all computed at the same rates within the two groups (a point to which we return below), the results overall are in line with the uniformity prediction we identified for the implicature approach: adults computed more multiplicity and abundance inferences in positive than in negative contexts, and computed more of both than children, in parallel with the merika ‘some’ targets. The pattern of analogous differences between children and adults in all three inferences, in combination with the effect of polarity, is in line with an implicature account of multiplicity and abundance inferences, and suggests a unification of the effects of plural morphology across the mass and count divide.

5.1.1 Sensitivity to polarity

One of the main findings of the present study is that both multiplicity and abundance inferences in Greek are sensitive to polarity. That is, adults gave significantly more inference-consistent responses in the positive condition than they did in the negative condition, rejecting sentences like those in (68) and (69) in contexts in which the tiger fed exactly one pig and in which the zebra dropped a small amount of sugar, respectively.

This observed sensitivity to monotonicity is in line with previous results reported for English in Tieu et al. (2014; 2018), and is unsurprising on both the ambiguity and the implicature approaches.

5.1.2 Response patterns for positive and negative targets

The results also clearly show that adults responded differently to the positive and negative cases: they tended to give the intermediate value in the positive case but the lowest value in the negative case, as can be seen in Figures 3 and 4. This pattern is in line with – and even expected on – the implicature approach, which can account for the pattern straightforwardly by mapping the lowest value to falsity of the literal meaning and the intermediate value to the falsity of the implicature. By contrast, it is less clear how the ambiguity approach might capture this difference between the positive and negative response patterns, since it does not predict any difference in the status of the source of rejection in the positive and negative cases.²⁴ In sum, the asymmetry across the polarities in adults is more in line with the implicature approach than the ambiguity approach.²⁵