Upon hearing the phrase Some cats meow, a listener might pragmatically infer that ‘Some but not all cats meow’. This is known as a scalar implicature and it often arises when a speaker produces a weak linguistic expression instead of a stronger one. Several L2 studies claim that pragmatic inferences are generated by default and their comprehension presents no challenges to L2 learners. However, the evidence obtained from these studies largely stems from offline-based tasks that provide limited information about how scalar implicatures are processed. This study investigated scalar implicature processing among L2 speakers of English and the degree to which differences in L2 proficiency and Theory of Mind abilities would modulate pragmatic responding. The experiment used an online sentence verification paradigm that required participants to judge, among multiple control items, the veracity of under-informative sentences, such as Some cats are mammals, and to respond as quickly as possible. A true response to this item is indicative of a logical some and perhaps all reading and a false response to a pragmatic some but not all reading. Our results showed evidence that scalar inferences are not generated by default. The answer linked to the pragmatic reading some but not all took significantly longer to make relative to the answer that relies on the logical interpretation some and perhaps all. This processing slowdown was also significantly larger among participants with lower English proficiency. Further exploratory analyses of participants’ Theory of Mind, as measured by the Social Skill subscale in the Autism Spectrum Quotient, revealed that socially inclined participants are more likely than the socially disinclined to derive a scalar inference. These results together provide new empirical insights into how L2 learners process scalar implicatures and thus implications for processing theories in experimental pragmatics and second language acquisition.

Research in Experimental Pragmatics has shown that deriving scalar implicatures involves effort and processing costs. This finding was robust and replicated across a wide variety of testing techniques, logical terms, populations, and languages. However, a question that remains disputed in the literature is whether this observed processing cost is a product of the inferential process itself or other logical properties whose computation taxes cognitive resources independently of the inferential mechanism. This paper has two objectives: one is to review the previous experimental work on scalar implicatures and how it evolved in the literature, and the other is to discuss possible factors that render computing scalar implicatures cognitively effortful. Implications and directions for future research are provided.

When we say that Some people have lungs, we implicate that not all people have lungs. This scalar implicature arises when we produce a weaker expression instead of a stronger one. Studies on bilingual adults suggest that L2 learners, regardless of their proficiency level, are sensitive to under-informative sentences and they exhibit a superior pragmatic ability on a par with monolingual control groups. However, the evidence obtained from these studies is largely one-dimensional stemming from offline tasks that provide limited information about scalar implicature processing. The present study addressed this issue by investigating scalar implicature computation among L2 adults using an online sentence verification paradigm similar to that of Bott and Noveck whereby participants are required to judge the veracity of categorical under-informative sentences. The study also examined how individual differences in personality traits and L2 proficiency level would modulate participants’ pragmatic responses and processing times. Our results showed that those with weaker English proficiency tended to be significantly less sensitive to implicatures than those with proficiency advantage. The two proficiency groups also took significantly longer processing times to compute the pragmatic interpretation than the logical interpretation. The results further revealed that the pragmatic responses and their processing slowdowns were influenced by various personality and autistic traits. Our findings provide novel empirical insights into how L2 learners process scalar implicatures, and thus useful implications for the processing theories in experimental pragmatics and second language acquisition.

For more than 20 years, studies in experimental pragmatics have provided invaluable insights into the cognitive processes involved in deriving scalar implicatures and achieving inferential comprehension. However, the reports have always contained a notable degree of variability that remained inadequately discussed in the literature. For instance, upon closer inspection of the experimental record, one can always find a group of individuals who tend to be largely pragmatic, overwhelmingly logical, or sometimes mixed not showing a clear preference. There also exist newly-devised paradigms that prompt a radically different type of response than other paradigms, and thus new evidence casting doubt on long-established findings in the field. More recent research on scalar diversity further suggests that differences in the semantic structure of scalar words can lead to differing rates of scalar implicatures and can modulate the time invested in pragmatic processing. Indeed, one can contend that the current empirical landscape on scalar implicatures can be characterized as having three primary sources of variability: inter-individual, methodological, and linguistic. What factor or factors are behind these patterns of variability, and how can we interpret them in light of a pragmatic theory? This paper has a 2-fold objective: one is to review the previous experimental record on scalar implicatures from variability-based lenses, and the other to discuss the factor(s) that could account for this observed variability in the literature. Avenues for future research are provided.