Isabel Orenes

Negation: A theory of its meaning, representation, and use

This article presents a model-based theory of what negation means, how it is mentally represented, and how it is understood. The theory postulates that negation takes a single argument that refers to a set of possibilities and returns the complement of that set. Individuals therefore tend to assign a small scope to negation in order to minimize the number of models of possibilities that they have to consider. Individuals untrained in logic do not know the possibilities corresponding to the negation of compound assertions formed with if, or, and and, and have to infer the possibilities one by one. It follows that negations are easier to understand, and to formulate, when individuals already have in mind the possibilities to be negated. The paper shows that the evidence, including the results of recent studies, corroborates the theory.

Schizotypal people stick longer to their first choices.

Many studies have reported that schizophrenic patients show a Bias Against Disconfirmatory Evidence (BADE). This cognitive bias has been related to the formation and maintenance of delusion. The aim of this paper was to study whether BADE was present in healthy people displaying psychometric schizotypy, and to compare a closure task, which has been used for schizophrenia, with a new chronometric paradigm. Results with the new paradigm showed that the high-schizotypy group maintained their initial hypotheses longer than the low-schizotypy group. This finding corroborated the similarities between schizophrenic disorder and schizotypal traits, in this case with respect to the BADE. Research of this kind could facilitate the study of cognition in the schizophrenic spectrum without the difficulties of working with schizophrenic patients for some tasks and the assessment and early intervention in at-risk populations.

Negation in context: Evidence from the visual world paradigm.

Literature assumes that negation is more difficult to understand than affirmation, but this might depend on the pragmatic context. The goal of this paper is to show that pragmatic knowledge modulates the unfolding processing of negation due to the previous activation of the negated situation. To test this, we used the visual world paradigm. In this task, we presented affirmative (e.g., her dad was rich) and negative sentences (e.g., her dad was not poor) while viewing two images of the affirmed and denied entities. The critical sentence in each item was preceded by one of three types of contexts: an inconsistent context (e.g., She supposed that her dad had little savings) that activates the negated situation (a poor man), a consistent context (e.g., She supposed that her dad had enough savings) that activates the actual situation (a rich man), or a neutral context (e.g., her dad lived on the other side of town) that activates neither of the two models previously suggested. The results corroborated our hypothesis. Pragmatics is implicated in the unfolding processing of negation. We found an increase in fixations on the target compared to the baseline for negative sentences at 800 ms in the neutral context, 600 ms in the inconsistent context, and 1450 ms in the consistent context. Thus, when the negated situation has been previously introduced via an inconsistent context, negation is facilitated.

Context effects on the spontaneous production of negation

Abstract There has been a substantial amount of research that has examined how context affects peoples understanding of negation. Many authors argue that negation is more plausible or natural in some contexts than in others. For these authors, it is reasonable to negate a proposition only when it is presupposed. However, this assumption has been indirectly inferred from comprehension studies. None of them checked if the frequency of the spontaneous use of negation depends on the context. In this paper we present two experiments on this topic. The participants read stories where a sentence is false; and were asked to produce a sentence that could be true. In the first experiment they produced more negations from multiple than from bipolar contexts (e.g., when the false sentence was “the car was red” as compared to “the car was big”). In the second experiment the context was logically dichotomized by adding disjunctions. In this case, incongruent contexts enhanced the use of negation. The results seem to support the idea that when there is a clear alternative, negation is seldom spontaneously produced even if it denies a presupposition.

Visual content of words delays negation

Many studies have shown the advantage of processing visualizable words over non-visualizables due to the associated image code. The present paper reports the case of negation in which imagery could slow down processing. Negation reverses the truth value of a proposition from false to true or vice versa. Consequently, negation works only on propositions (reversing their truth value) and cannot apply directly to other forms of knowledge representation such as images (although they can be veridical or not). This leads to a paradoxical hypothesis: despite the advantage of visualizable words for general processing, the negation of clauses containing words related to the representation of an image would be more difficult than negation containing non-visualizable words. Two experiments support this hypothesis by showing that sentences with a previously negated visualizable word took longer to be read than sentences with previously negated non-visualizable words. The results suggest that a verbal code is used to process negation.