Plural morphology in English is associated with a multiplicity inference. For example, “Emily fed giraffes” is typically interpreted to mean that Emily fed multiple giraffes. It has long been observed that this inference disappears in downward-entailing linguistic environments, such as in the scope of negation. For example, “Emily didn't feed giraffes” does not merely suggest that she didn't feed multiple giraffes, but rather that she didn't feed any. There are three main approaches to explaining this puzzle: the first proposes that the plural is ambiguous, and invokes a preference for stronger meanings; the second derives multiplicity inferences as implicatures; and the third provides a homogeneity-based account. These different approaches can all account for the interpretation of the plural across upward- and downward-entailing environments. They differ, however, in what they predict for three further aspects of the plural: the status of positive and negative plural sentences in singular contexts, children's acquisition of plural meanings, and the relationship between plural meanings and scalar implicatures. In this paper, we report on three experiments investigating adults' and preschool-aged children's interpretation of plural morphology in English. The experiments reveal that participants distinguish positive and negative plural sentences presented in singular contexts, and that adults assign a different status to these positive and negative sentences. It is also observed that children, unlike adults, tend to accept underinformative positive plural sentences in singular contexts — in parallel with their behavior on standard scalar implicatures — while they are relatively more adult-like when it comes to negative plural sentences in the same contexts, showing a tendency to reject the negative sentences. We discuss how the findings of the three experiments are expected on a scalar implicature approach to multiplicity inferences, and the open challenges they pose for the ambiguity and homogeneity approaches.

英语中的复数形态与多重推理有关。例如，“艾米丽馈送长颈鹿小号”通常解释为意味着艾米丽馈送多个长颈鹿。长期以来，人们一直观察到这种推论在向下的语言环境中消失了，例如在否定的范围内。例如，“艾米莉没有喂养长颈鹿”不仅表明她没有喂养多头长颈鹿，而且还表明她没有喂养任何长颈鹿。可以通过三种主要方法来解释此难题：第一种方法认为复数是模棱两可的，并调用偏好更强的含义；第二个推导多重性暗示。第三个提供基于同质性的帐户。这些不同的方法都可以解释在向上和向下的环境中对复数的解释。但是，它们在对复数的三个其他方面的预测方面有所不同：在单数上下文中正负复数句子的状态，儿童对复数含义的习得以及复数含义与标量含意之间的关系。在本文中，我们报告了三个实验，研究成年人和学龄前儿童对英语的复数形态的解释。实验表明，参与者可以区分以单数形式出现的正负复数句子，而成年人给这些肯定和否定句子赋予了不同的地位。还观察到，与成年人不同，儿童倾向于接受信息不足的信息在单数语境中的肯定复数句子-与它们在标准标量含义上的行为并行-在相同语境中涉及否定复数句子时，它们相对来说更像成年人，表现出拒绝否定句子的倾向。我们讨论了如何在标量隐式方法上对这三个实验的结果进行多重推理，以及它们对歧义和同质性方法提出的开放性挑战。