A Corpus of Negations and their Underlying Positive Interpretations

Proceedings of the Eighth Joint Conference on Lexical and Computational Semantics (*SEM), pages 158–167 Minneapolis, June 6–7, 2019. c⃝2019 Association for Computational Linguistics 158 A Corpus of Negations and their Underlying Positive Interpretations Zahra Sarabi, Erin Killian, Eduardo Blanco and Alexis Palmer University of North Texas zahrasarabi@my.unt.edu, erinkillian@my.unt.edu, eduardo.blanco@unt.edu, alexis.palmer@unt.edu Abstract Negation often conveys implicit positive meaning. In this paper, we present a corpus of negations and their underlying positive in- terpretations. We work with negations from Simple Wikipedia, automatically generate po- tential positive interpretations, and then col- lect manual annotations that effectively rewrite the negation in positive terms. This proce- dure yields positive interpretations for approx- imately 77% of negations, and the final corpus includes over 5,700 negations and over 5,900 positive interpretations. We also present base- line results using seq2seq neural models. 1 Introduction Negation is present in every human language. It is in the first place a phenomenon of semantical opposition. As such, negation relates an expres- sion e to another expression with a meaning that is in some way opposed to the meaning of e (Horn and Wansing, 2015). Sentences containing nega- tion are generally (a) less informative than affir- mative ones (e.g., Milan is not the capital of Italy vs. Rome is the capital of Italy), (b) morphosyn- tactically more marked—all languages have neg- ative markers while only a few have affirmative markers, and (c) psychologically more complex and harder to process (Horn and Wansing, 2015). Negation often conveys implicit positive mean- ings (Rooth, 1992). This meaning ranges from im- plicatures to entailments, and we refer to it as pos- itive interpretations. Consider the following text from Simple Wikipedia:1 An abjad is an alpha- bet in which all its letters are consonants. Though vowels can be added in some abjads, they are not needed to write a word correctly. Some exam- ples of abjads are the Arabic alphabet and the 1https://simple.wikipedia.org/wiki/ Abjad 1 Mr. Smith apologized for :: not getting involved. Mr. Smith apologized for staying passive. 2 I :::: never heard of this guy before they started doing these commercials on television and radio. I heard of this guy after they started doing these com- mercials on on television and radio. 3 In Hinduism, beef is :: not allowed to be eaten. In Hinduism, chicken is allowed to be eaten. In other religions, beef is allowed to be eaten. Table 1: Three sentences containing a negation and their positive interpretations (italics). Hebrew alphabet. Humans intuitively understand that the negation (second sentence) implies the following positive interpretation: Though vowels can be added in some abjads, only consonants are needed to write a word correctly. Table 1 shows three sentences containing negation and their un- derlying positive interpretations. Positive interpre- tations do not have any negation cues (e.g., not, never) and Example 3 shows that some negations may have more than one underlying positive inter- pretation depending on the context. Revealing the underlying positive interpretation of negation is challenging. First, we need to iden- tify which …

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