Participants were given counterfactual sentences-for example, "If Mary had won the lottery she would have bought a Mercedes car"-or factual sentences-for example, "Because Mary won the lottery, she bought a Mercedes car"-embedded in short narratives. Reading times showed that readers were immediately sensitive to the special status of counterfactual information (Experiment 1). In addition, probe-recognition latencies demonstrated that old information was more accessible in counterfactual than in factual stories, and new information was equally accessible in both kinds of stories (Experiment 2). However, after reading additional clauses, new information became less accessible in counterfactual than in factual stories (Experiment 3). These results suggest that counterfactual events are momentarily represented but are later suppressed and the readers' attention goes back to previous events in the story.
We use language to describe facts: namely, what happened, is happening, or could happen. But we are also very skillful at producing and understanding counterfactual sentences such as "If Mary had won the lottery, she would have bought a Mercedes car."1 Counterfactual meaning has an unreal status, because it refers to a past event that did not happen and to the equally unreal consequence of such event. Counterfactuals might seem a pointless activity: Why do we expend our time and mental resources using expressions that do not describe real events or even possible future events? However, counterfactuals are a pervasive aspect of human mental life. The reasoning and social psychology literature provides wide evidence of the psychological functions of counterfactual thinking (see Byrne, 2002, 2005; Roese, 1997, 2005). Counterfactuals allow us to learn from mistakes; for instance, "If I had prepared for the exam I would have gotten an A score" may persuade the speaker to prepare better for the exam next time (Roese, 1994). By contrasting the outcome of an event with its counterfactual alternatives, people can work out causal judgments (Harris, German, & Mills, 1996). Thus the counterfactual "If only John had been so kind as to bring me to the airport, I would have made it to my plane on time" allows the speaker to explain why she has missed her plane, attributing the responsibility to John's lack of kindness. In the same vein, counterfactual simulations of alternatives could be generated to predict the probability of an event (Kahneman & Tversky, 1982). Finally, counterfactuals are emotional amplifiers that may result in social emotions of regret, guilt, or blame, as well as in the more positive emotions of relief or satisfaction (Byrne, 2002; Guttentag & Ferrell, 2004; Johnson-Laird & Byrne, 2002; Kahneman & Miller, 1986).
In contrast to the amount of attention paid to counterfactual thinking, the study of counterfactual comprehension has been neglected by psycholinguists and discourse researchers. This neglect is not justifiable, because counterfactuals are produced not only to accomplish speakers' personal goals but also to be understood by addressees. The aim of this article is to explore the comprehension of counterfactuals embedded in texts using reading times and accessibility measures. In spite of the lack of specific research on the comprehension of counterfactuals, we will review literature relevant to the present subject. First, we will describe theoretical approaches to counterfactual meaning according to cognitive linguistics and the conditional reasoning literature; second, we will focus on the notion of updating, which is central to explaining the hypotheses of the present research; and finally we will describe studies on the comprehension of mentalist expressions that share characteristics with counterfactuals.
A popular hypothesis in cognitive linguistics is that understanding counterfactuals involves the representation of two possible states of the world (Fauconnier, 1994; Langacker, 1991). …