Under the assumption of the principle of cooperation (Grice, 1989), a statement such as "some eels are fish" is thought to be false since it contains less information than is considered sufficient. However, the statement is logically sound since the meaning of "some" is compatible with "all". Currently, the primary interpretation of such underinformative statements remains subject to debate. According to Levinson (2000), the pragmatic "some but not all" interpretation is the default interpretation, while others (e.g., Sperber & Wilson, 1995) argue that this pragmatic interpretation only comes to the fore when relevant within the context and is thus considered secondary to the logical "some and perhaps all" interpretation. In this study, three factors that may influence the answer pattern are studied: task load, working memory capacity, and repetition of the statements. In Experiment 1, we used a secondary task paradigm to manipulate the cognitive load under which a number of underinformative statements had to be judged. We observed that for participants with a rather limited working memory span it is harder to reach a pragmatic interpretation under cognitive load. In Experiment 2, we manipulated the repetition of the statements. We observed that with a higher number of filler statements, participants produced fewer consistent answer patterns. This study provides further evidence against the automaticity of the pragmatic interpretation: It shows that the pragmatic interpretation requires more cognitive effort than the logical interpretation and that increasing the number of filler statements inhibits the development of a response strategy.

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Research in the psychology of mathematics education has been confronted with the fact that people blatantly fail to solve tasks they are supposed to be able to solve correctly given their available domain-specific knowledge and skills. Also researchers in cognitive psychology have encountered such phenomena. In this paper, theories that have been developed in both fields to account for these findings are discussed. After giving a summary of the state of the art in both fields, we argue that bringing together these largely separately developed (sets of) theories creates opportunities for both domains and we suggest a way in which this can be done.

The present study interprets the overuse of proportional solution methods from a dual process framework. Dual process theories claim that analytic operations involve time-consuming executive processing, whereas heuristic operations are fast and automatic. In two experiments to test whether proportional reasoning is heuristic-based, the participants solved "proportional" problems, for which proportional solution methods provide correct answers, and "nonproportional" problems known to elicit incorrect answers based on the assumption of proportionality. In Experiment 1, the available solution time was restricted. In Experiment 2, the executive resources were burdened with a secondary task. Both manipulations induced an increase in proportional answers and a decrease in correct answers to nonproportional problems. These results support the hypothesis that the choice for proportional methods is heuristic-based.

Return of fear after successful exposure therapy calls for a better understanding of the mechanisms of relapse. Classical conditioning research provides a useful framework for conceptualising the acquisition, extinction and reappearance of fear. The present paper focuses on reinstatement, the return of extinguished conditioned responses due to the experience of one or more unconditioned stimuli (USs) after extinction. This phenomenon illustrates that unpredictable USs can lead to a return of fear after successful exposure.The data we present is one of the first demonstrations that conditioned suppression of instrumental behaviour can be used as an index of classical conditioning in laboratory mice. The procedure proves to be a promising instrument for assessing fear in mice, both in the context of research aimed at unravelling the functional characteristics of learning and memory in healthy mice and in the context of research aimed at unravelling the neurobiological substrate of psychiatric disorders, e.g., in studies with transgenic and knockout mice. Using this procedure, we report the first observation of reinstatement of conditioned suppression in this species.