Investigating the Comprehension of Negated Sentences Employing World Knowledge: An Event-Related Potential Study

Abstract

Previous event-related potential (ERP) studies comparing affirmative and negative sentences revealed an N400 for semantically mismatching final words, resulting in a larger N400 for false relative to true affirmative sentences and an opposite effect for negative sentences. Hence, the N400 was independent of the presence of a negation. However, the true negative as well as the false affirmative condition often contained entities or features from different semantic categories and thereby with weak feature overlap, such as e.g., A cat is (not) a saw or Fears are (not) round, which were then compared to true affirmative and false negative sentences containing entities with stronger feature overlap and partially even hyponomy relations, e.g., A cat is (not) an animal or Planets are (not) round. Employing world-knowledge variations, in the current study, we investigate whether increasing the feature overlap between the entities of all conditions leads to similar ERP-patterns as in the previous studies. For this purpose, we use sentences of the following type: George Clooney is (not) an actor vs. George Clooney is (not) a singer where both target words describe a similar profession and thereby function as alternatives to each other. However, in line with the previous studies, we find a truth by polarity interaction, namely, the N400 ERPs are significantly larger for false compared to true affirmative sentences, whereas the effect for negative sentences shows a reversed, though not significant, trend. Overall, the ERP-data suggest that the integration of a negation with the information in its scope is neither fully incremental nor fully delayed, which might be linked to the use of cohyponyms and to the increased feature overlap between alternatives (e.g., actor, singer). Additionally, questionnaire-based rating data show that affirmative sentences are perceived as more natural than negative sentences, and, moreover, that true sentences are perceived as more natural than false sentences, independent of their polarity.

Informative use of “not” is N400‐blind

“…The N400 also arises as an inverse measure of priming: an unprimed word results in an N400 compared to the same word in a primed context (Kutas, Van Petten, & Besson, 1988), raising the possibility that the N400 effect in affirmatives is instead a lexical priming effect. This confound was experimentally controlled by Haase et al (2019), who replicated previous negation-blind N400 results. 1 This suggests that the negation-blind N400 pattern is not simply a function of semantic priming.…”

“…This confound was experimentally controlled by Haase et al. (2019), who replicated previous negation‐blind N400 results. This suggests that the negation‐blind N400 pattern is not simply a function of semantic priming.…”

“…In the sentence “A hammer is not a bird,” negation is computed as a logical operator that takes the entire proposition as its argument: not(a hammer is a bird) , necessitating two steps of processing. ERP studies showing apparently “negation‐blind” results have been interpreted to support this two‐step model (Dudschig, Mackenzie, Leuthold, & Kaup, 2018; Fischler, Bloom, Childers, Roucos, & Perry, 1983; Haase, Spychalska, & Werning, 2019; Lüdtke, Friedrich, De Filippis, & Kaup, 2008; Wiswede, Koranyi, Müller, Langner, & Rothermund, 2013). We conducted a replication of Fischler et al’s study and found that simple class‐inclusion sentences still exhibit negation blindness even when presented in a more meaningful context.…”

“…This suggested that “bird” was interpreted by the brain as an unexpected continuation of both “A hammer is…” and “A hammer is not…,” even though one sentence is false and the other is true. This has become known as “negation blindness” and offers direct support for the two‐step processing model (Fischler et al., 1983; Haase et al., 2019). The negation‐blind N400 pattern is illustrated in Table 1.…”

The Role of Alternatives in Language

“…There have been numerous studies investigating the role of pragmatic felicity in relation to semantic and world knowledge, amongst them two studies that have appeared in the Research Topic The Role of Alternatives in Language (2019). Haase et al (2019) RT investigated pragmatic plausibility via the co-hyponym relation such that there is a large semantic feature overlap between alternatives (unlike for birds and trees), and both alternatives in principle would be pragmatically plausible in a sentence such as George Clooney is (not) an actor/singer. Haase et al employed the method of event-related brain potentials, which in earlier research yielded the result that for stimulus sets without pragmatic control the N400 component on the final word is larger for false than for true affirmative sentences, whereas for negative sentences it is the other way round (e.g., Fischler et al, 1983;Kounios and Holcomb, 1992;Lüedtke et al, 2008;Nieuwland and Kuperberg, 2008;Wiswede et al, 2013;Dudschig et al, 2016; for early research using behavioral methods reporting this truth-polarity interaction, see e.g., Wason and Jones, 1963;Gough, 1965;Clark and Chase, 1972;Carpenter and Just, 1975; for a recent review also on findings not showing the interaction, see Kaup and Dudschig, 2020).…”