ABSTRACT
In their prominent book entitled If, Evans and Over (2004) noted that this word is one of the most important and interesting words in language, because it conveys the hypothetical thinking by which humans go beyond the actual states of the world, imagining alternative possibilities, testing predictions in scientific experimental settings, and finally creating novelty. If is certainly one of the most important and interesting words in human language, but also one of the most complex. Indeed, developmental studies have revealed that its meaning is not mastered until late adolescence (see for example Barrouillet & Lecas, 1998; Daniel & Klaczynski, 2006), and even educated adults often experience surprising difficulties when reasoning from If sentences, as studies of the famous Wason’s selection task or conditional syllogisms have demonstrated. Such complexity in so short a word has motivated a variety of theoretical proposals to account for the way humans understand conditionals and reason from them (Braine & O’Brien, 1991; Evans & Over, 2004; Evans, Over, & Handley, 2005; Johnson-Laird & Byrne, 2002; Johnson-Laird, Byrne, & Schaeken, 1992).
