ABSTRACT
The difficulty for cognitive scientists is that what they need to hypothesise in order to explain how the mind works is not available to introspection. So, they have to focus on behavioural data. Scientists interested in human reasoning have paid attention to the time it takes for solving a problem (that is, the latencies) and to the answers that reasoners produce. With respect to the latter dependent variable, much attention has been devoted to the rate of correct responses: This rate gives an indication of the difficulty of the problem, which can lead to interesting hypotheses about the underlying reasoning processes. Scientists, however, not only look at the number of correct responses. For instance, numerous studies have examined the type of valid and invalid responses in syllogistic reasoning, discovering that the figure of a syllogism affects the form of the conclusions that reasoners draw, accuracy, and speed (e.g., Johnson-Laird & Bara, 1984)
Strangely, such an analysis of the nature of the valid and invalid responses is absent in the field of relational reasoning. In the present chapter, we want to address this topic. First, we give a brief account of two theories of relational reasoning. Next, we discuss the issue of cognitive economy in reasoning. This will lead to a first experiment about task instructions and an indeterminacy-shortcut strategy. Finally, we describe two experiments that investigate the type of invalid responses to problems for which the correct response is “nothing follows”.
