When fast logic meets slow belief: Evidence for a parallel-processing model of belief bias

Abstract

Two experiments pitted the default-interventionist account of belief bias against a parallel-processing model. According to the former, belief bias occurs because a fast, belief-based evaluation of the conclusion pre-empts a working-memory demanding logical analysis. In contrast, according to the latter both belief-based and logic-based responding occur in parallel. Participants were given deductive reasoning problems of variable complexity and instructed to decide whether the conclusion was valid on half the trials or to decide whether the conclusion was believable on the other half. When belief and logic conflict, the default-interventionist view predicts that it should take less time to respond on the basis of belief than logic, and that the believability of a conclusion should interfere with judgments of validity, but not the reverse. The parallel-processing view predicts that beliefs should interfere with logic judgments only if the processing required to evaluate the logical structure exceeds that required to evaluate the knowledge necessary to make a belief-based judgment, and vice versa otherwise. Consistent with this latter view, for the simplest reasoning problems (modus ponens), judgments of belief resulted in lower accuracy than judgments of validity, and believability interfered more with judgments of validity than the converse. For problems of moderate complexity (modus tollens and single-model syllogisms), the interference was symmetrical, in that validity interfered with belief judgments to the same degree that believability interfered with validity judgments. For the most complex (three-term multiple-model syllogisms), conclusion believability interfered more with judgments of validity than vice versa, in spite of the significant interference from conclusion validity on judgments of belief.Electronic supplementary materialThe online version of this article (doi:10.3758/s13421-016-0680-1) contains supplementary material, which is available to authorized users.

At the core of reasoning: Dissociating deductive and non‐deductive load

“…First, although our behavioral results replicate the classic differential performance across modus ponens and modus tollens type inferences, accuracy in the modus tollens type inferences was higher than typically reported in classic studies (i.e., 87% in our work vs. 63% in Taplin, 1971; 62% in Wildman & Fletcher, 1977). Nonetheless, our accuracy rates are in line with a number of behavioral and neuroimaging reports (e.g., 94% in Prado et al , 84% in Luo, Yang, Du, & Zhang, ; between 80% and 88% in Bloomfield & Rips ; 79% in Knauff et al, ; 78% in Trippas, Thompson, & Handley, ; 75% in Evans, 1977; and above 90% in the Wason Selection Task as implemented in Li, Zhang, Luo, Qiu, & Liu, , Qiu et al, , Liu et al, ) as well as developmental work showing that by age 16 accuracy rates for modus tollens range between 78% and 87% (Daniel et al, 2006). We do stress, however, that although our participants did not undergo any overt training (e.g., training to criterion; see for example Reverberi et al, ) and reported no formal training in logic, our procedure selected high‐performance individuals in the sense that they had to meet a 60% accuracy criterion across each of the four conditions (complex/simple, deductive/non‐deductive).…”

Conflict Detection and Logical Complexity

“…While there is empirical support for the additional cognitive challenge that negation provides (Schaeken & Schroyens, 2000; Schroyens et al, 2000, 2001), it might not be strong enough for us to observe differences in conflict detection. This possibility would be congruent with the results of Trippas et al (2017), who indicated in their supplementary material that they found no significant difference in conflict detection between the propositional versions of MP and MT, but still reported smaller conflict detection effects for syllogisms of greater complexity than MT. Combined with these results, our study suggests that MT might be simple enough for people to develop an intuitive grasp of its structure.…”

“…Note that, while conflict detection on propositional versions of MP and MT has been previously observed (Trippas et al, 2017), to our knowledge, our studies are the first to manipulate complexity with these categorical items and with these four inferences forms.…”

“…However, recent studies have explored the possibility of a reversed phenomenon, that is, the possibility that the logical validity of an argument may bias judgments of believability. These studies presented participants with inferences where logic and belief were in accordance or in conflict and instructed them to evaluate their conclusions’ believability (Handley & Trippas, 2015; Trippas, Thompson, & Handley, 2017) or likability and brightness (Trippas, Handley, Verde, & Morsanyi, 2016) in a short period of time. They found that people needed more time and were more prone to errors when the logical validity of the problems conflicted with the conclusion’s believability.…”

Characterizing Belief Bias in Syllogistic Reasoning: A Hierarchical-Bayesian Meta-Analysis of ROC Data

“…However, note that other options are available, including the use of a dynamic discrete-state model approach (e.g., Klauer, 2018). Although response times have not played a significant role in this literature, they nevertheless introduce important theoretical constraints (e.g., Trippas et al, 2017). This state of affairs is partly due to the difficulties associated with fitting such models when individual data are sparse.…”