Based on an impressive amount of data from a sustained research program over many years, Byrne (Reference Byrne2005) presents an exciting theoretical framework for how we think about alternatives to reality. We focus on two points: (1) counterfactuals as dual possibilities, and (2) the cognitive processes involved in counterfactual thinking; and we comment on them from a developmental perspective.
Counterfactuals as dual possibilities
Based on her work with adults, Byrne claims that counterfactuals are represented as dual possibilities. Given that children first start to pass explicit tests of counterfactual thinking at around age 3 or 4 years, it seems reasonable to infer that children also represent counterfactuals as possibilities at this age. However, in one recent study 4-year-olds who could correctly answer a question that referred to a counterfactual event of the type, “What if X had happened, how would the world be?” were unable to acknowledge that at a previous point in time either the counterfactual or actual event could have occurred (Beck et al. Reference Beck, Robinson, Carroll and Apperly2006). Our interpretation of this finding is that when children first start to think counterfactually they think only about what did not happen, but do not relate it to, or represent, the actual world explicitly. Thus, early counterfactual thinking might not involve thinking about possibilities, even though it does involve thinking about what might have been.
Cognitive processes
Throughout the book Byrne suggests that differences in working memory may be responsible for both individual differences and developmental changes in counterfactual thinking. Byrne argues, quite reasonably, that pre-school children find counterfactual conditionals, “What if X had not happened, how would the world be?” more difficult than simple causal conditionals, “What if X happens, how will the world be?” (see Riggs et al. Reference Riggs, Peterson, Robinson and Mitchell1998) because counterfactuals make the greater working memory demands (we also know that working memory develops substantially in the pre-school years). While the case for adult variation in counterfactual thinking (and working memory) is supported by empirical evidence, there is little or no evidence to suggest that working memory underpins early developments in counterfactual thinking.
Recently, we tested Byrne's idea (Beck et al. submitted). We asked 3- and 4-year old children counterfactual conditional questions of the sort used by Riggs and colleagues (Reference Riggs, Peterson, Robinson and Mitchell1998) and also gave them a battery of executive function tasks. We found that once receptive vocabulary and age were taken into account, working memory did not predict counterfactual thinking ability. Rather, we found that inhibitory control predicted success on counterfactual conditional tasks, independently of age, language, and working memory (though, interestingly, inhibitory control did not predict success on counterfactual syllogistic reasoning tasks).
Current evidence suggests that developments in counterfactual thinking continue after the pre-school years and comes from the literature on regret (Guttentag & Ferrell Reference Guttentag and Ferrell2004). Children's evaluations of who will feel regretful are not influenced by counterfactual possibilities until they are at least 7 years old. Given that children do not make the comparison between how things are and how things could have been suggests to us that they are not holding both possible worlds in mind. We agree with Byrne that working memory should be implicated in counterfactual thinking when one holds in mind both the counterfactual and the actual possibility; and for this reason we predict that developments in working memory underpin the ability to understand counterfactual emotions.
In short, we are in agreement with Byrne that mature counterfactual thinking requires representing dual possibilities. But we do not think this ability develops at around 3 or 4 years of age. At this age there are developments in the ability to consider alternatives to reality, but this ability appears to be related to improvements in inhibitory control, not working memory. Recent evidence suggests that representing counterfactuals as possibilities (what we might think of as genuine or adult-like counterfactual thinking) develops later, in middle childhood, which may well be driven by developments in working memory (though inhibitory control may also play a role).
Byrne's framework will prove to be immensely helpful to developmental psychologists who question when and how children engage in imaginative reasoning, including object substitution pretence, counterfactual conditional reasoning, and syllogistic reasoning with false premises. Furthermore, the book raises a number of other topics for future developmental research programs. However, we also believe that a developmental perspective on many of these issues will provide a richer and ultimately more comprehensive account of what it means to be able to consider alternatives to reality.
