The effects of strength and activation level of belief on belief-biased reasoning.

The belief bias effect designates the tendency to judge the validity of a conclusion based on its believability. Most studies have compared highly believable with unbelievable conclusions when examining belief-biased reasoning. In two studies, we examine a hypothesis raised by Banks (2013, Cognitive Science, 37[3], 544-577), who postulated that level of activation of belief should affect the extent to which reasoning is biased. Here, a first study found that moderately believable conclusions produced a significant biasing effect, but one that was smaller than with highly believable conclusions. The second study found that activating the category referenced by a conclusion significantly increased the biasing effect of the same conclusion. These results suggest that strength of belief is a necessary parameter of any model of belief bias. They also show that context can affect the extent to which belief affects reasoning.

The paradoxical effects of time pressure on base rate neglect.

Base rate neglect refers to the well-documented tendency for people to primarily rely on diagnostic information to identify event probabilities while discounting information about relative probabilities (base rates). It is often postulated that using base rate information requires some form of working memory intensive processes. However, recent studies have put this interpretation into doubt, showing that rapid judgments can also lead to base rate use. Here we examine the idea that base rate neglect can be explained by the degree of attention paid to diagnostic information, which predicts that having more time should lead to greater rates of base rate neglect. Participants were presented with base rate problems either with a limited time to respond or with no time restrictions. Results show that having more time results in a decrease in base rate use.

Interpretation of ambiguous trials along with reasoning strategy is related to causal judgements in zero-contingency learning.

The dual strategy model suggests that people can use either a Statistical or a Counterexample reasoning strategy, which reflects two qualitatively different ways of processing information. This model has been shown to capture individual differences in a wide array of tasks, such as contingency learning. Here, we examined whether this extends to individual differences in the interpretation of contingency information where effects are ambiguous. Previous studies, using perceptually complex stimuli, have shown that the way in which participants interpret ambiguous effects predicts causal judgements. In two studies, we attempted to replicate this effect using a small number of clearly identifiable cues. Results show that the interpretation of ambiguous effects as effect present is related to final contingency judgements. In addition, results showed that Statistical reasoners had a stronger tendency to interpret ambiguous effects as effect present than Counterexample reasoners, which mediates the difference in contingency judgements.

Reasoning strategies and prior knowledge effects in contingency learning.

Prior knowledge has been shown to be an important factor in causal judgments. However, inconsistent patterns have been reported regarding the interaction between prior knowledge and the processing of contingency information. In three studies, we examined the effect of the plausibility of the putative cause on causal judgments, when prior expectations about the rate at which the cause is accompanied by the effect in question are explicitly controlled for. Results clearly show that plausibility has a clear effect that is independent of contingency information and type of task (passive or active). We also examined the role of strategy use as an individual difference in causal judgments. Specifically, the dual-strategy model suggests that people can either use a Statistical or a Counterexample strategy to process information. Across all three studies, results showed that Strategy use has a clear effect on causal judgments that is independent of both plausibility and contingency.