Indicative conditionals are known to have the semantic property of nonveridicality, that is, they do not entail the truth of the antecedent. In this paper, I argue that the nonveridicality property of indicative conditionals is elastic in that it can be affected by the choice of conditional connectives and negative polarity items. Two experiments are reported, one on German and the other on English. They show that in both languages, the presence of negative polarity items conveys a weakened speaker commitment towards the antecedent, although there is cross-linguistic variation concerning the effect of conditional connectives.

Negation is a universal component of human language; polarity sensitivity (i.e., lexical distributional constraints in relation to negation) is arguably so while being pervasive across languages. Negation has long been a field of inquiry in psychological theories and experiments of reasoning, which inspired many follow-up studies of negation and negation-related phenomena in psycholinguistics. In generative theoretical linguistics, negation and polarity sensitivity have been extensively studied, as the related phenomena are situated at the interfaces of syntax, semantics and pragmatics, and are thus extremely revealing about the architecture of grammar. With the now long tradition of research on negation and polarity in psychology and psycholinguistics, and the emerging field of experimental semantics and pragmatics, a multitude of interests and experimental paradigms have emerged which call for re-evaluations and further development and integration. This special issue contains a collection of 16 research articles on the processing of negation and negation-related phenomena including polarity items, questions, conditionals, and irony, using a combination of behavioral (e.g., rating, reading, eye-tracking and sentence completion) and neuroimaging techniques (e.g., EEG). They showcase the processing of negation and polarity with or without context, in various languages and across different populations (adults, typically developing and ADHD children). The integration of multiple theoretical and empirical perspectives in this collection provides new insights, methodological advances and directions for future research.

Existing work on the acquisition of polarity-sensitive expressions (PSIs) suggests that children show an early sensitivity to the restricted distribution of negative polarity items (NPIs), but may be delayed in the acquisition of positive polarity items (PPIs). However, past studies primarily targeted PSIs that are highly frequent in children’s language input. In this paper, we report an experimental investigation on children’s comprehension of two NPIs and two PPIs in German. Based on corpus data indicating that the four tested PSIs are present in child-directed speech but rare in young children’s utterances, we conducted an auditory rating task with adults and 11- to 12-year-old children. The results demonstrate that, even at 11–12 years of age, children do not yet show a completely target-like comprehension of the investigated PSIs. While they are adult-like in their responses to one of the tested NPIs, their responses did not demonstrate a categorical distinction between licensed and unlicensed PSI uses for the other tested expressions. The effect was led by a higher acceptance of sentences containing unlicensed PSIs, indicating a lack of awareness for their distributional restrictions. The results of our study pose new questions for the developmental time scale of the acquisition of polarity items.

In this paper, the meaning and processing of the German conditional connectives (CCs) such as wenn ‘if’ and nur wenn ‘only if’ are investigated. In Experiment 1, participants read short scenarios containing a conditional sentence (i.e., If P, Q.) with wenn/nur wenn ‘if/only if’ and a confirmed or negated antecedent (i.e., P/not-P), and subsequently completed the final sentence about Q (with or without negation). In Experiment 2, participants rated the truth or falsity of the consequent Q after reading a conditional sentence with wenn or nur wenn and a confirmed or negated antecedent (i.e., If P, Q. P/not-P. // Therefore, Q?). Both experiments showed that neither wenn nor nur wenn were interpreted as biconditional CCs. Modus Ponens (If P, Q. P. // Therefore, Q) was validated for wenn, whereas it was not validated in the case of nur wenn. While Denial of the Antecedent (If P, Q. not-P. // Therefore, not-Q.) was validated in the case of nur wenn, it was not validated for wenn. The same method was used to test wenn vs. unter der Bedingung, dass ‘on condition that’ in Experiment 3, and wenn vs. vorausgesetzt, dass ‘provided that’ in Experiment 4. Experiment 5, using Affirmation of the Consequent (If P, Q. Q. // Therefore, P.) to test wenn vs. nur wenn replicated the results of Experiment 2. Taken together, the results show that in German, unter der Bedingung, dass is the most likely candidate of biconditional CCs whereas all others are not biconditional. The findings, in particular of nur wenn not being semantically biconditional, are discussed based on available formal analyses of conditionals.

It is impossible to talk about human cognition without talking about concepts—there simply is no human cognition without concepts. Concepts form an abstraction of reality that is central to the functioning of the human mind. Conceptual knowledge (of e.g., APPLE, LOVE and BEFORE) is crucial for us to categorize, understand, and reason about the world. Only equipped with concepts and words for them can we successfully communicate and carry out actions. But what exactly are concepts? How are concepts acquired? How does the human mind use concepts? In this introduction chapter, we elaborate on these questions (i.e., representation, learning, application), and provide summaries of the seven individual chapters in the volume, which from different scientific disciplines relate to one or the other of the questions.