The Role of Syllogistic Reasoning in Inferences Based Upon New and Old Information *

We report research investigating the role of mental models in deduction. The first study deals with conjunctive inferences (from one conjunction and two conditional premises) and disjunctive inferences (from one disjunction and the same two conditionals). The second study examines reasoning from multiple conditionals such as: If e then b; If a then b; If b then c; What follows between a and c? The third study addresses reasoning from different sorts of conditional assertions, including conditionals based on if then, only if, and unless. The paper also presents research on figural effects in syllogistic reasoning, on the effects of structure and believability in reasoning from double conditionals, and on reasoning from factual, counterfactual, and semifactual conditionals. The findings of these studies support the model theory, pose some difficulties for rule theories, and show the influence on reasoning of the linguistic structure and the semantic content of problems.

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Reasoning Under Time Pressure

Experimental Psychology (formerly Zeitschrift für Experimentelle Psychologie) ◽

10.1027/1618-3169.56.2.77 ◽

2009 ◽

Vol 56 (2) ◽

pp. 77-83 ◽

Cited By ~ 35

Author(s):

Jonathan St. B. T. Evans ◽

Simon J. Handley ◽

Alison M. Bacon

Keyword(s):

Time Pressure ◽

Syllogistic Reasoning ◽

Conditional Inference ◽

Belief Bias ◽

Volitional Control ◽

Logical Validity

In this study, we examine the role of beliefs in conditional inference in two experiments, demonstrating a robust tendency for people to make fewer inferences from statements they disbelieve, regardless of logical validity. The main purpose of this study was to test whether participants are able to inhibit this belief effect where it constitutes a bias. This is the case when participants are specifically instructed to assume the truth of the premises. However, Experiment 1 showed that the effect is no less marked than when this instruction is given, than when it is not, although higher ability participants did show slightly less influence of belief (Experiment 2). Contrary to the findings with syllogistic reasoning, use of speeded tasks had no effect on the extent of the belief bias (both experiments), although it did considerably reduce the numbers of inferences that were drawn overall. These findings suggest that the belief bias in conditional inference is less open to volitional control than that associated with syllogistic reasoning.

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Role of the hippocampus during logical reasoning and belief bias in aging

10.1101/854208 ◽

2019 ◽

Author(s):

Maryam Ziaei ◽

Mohammad Reza Bonyadi ◽

David C. Reutens

Keyword(s):

Older Adults ◽

Logical Reasoning ◽

Syllogistic Reasoning ◽

Anterior Cingulate ◽

Correct Rejection ◽

Reasoning Task ◽

Cingulum Bundle ◽

Hippocampal Network ◽

Reasoning Tasks

AbstractReasoning requires initial encoding of the semantic association between premises or assumptions, retrieval of these semantic associations from memory, and recombination of information to draw a logical conclusion. Currently-held beliefs can interfere with the content of the assumptions if not congruent and inhibited. This study aimed to investigate the role of the hippocampus and hippocampal networks during logical reasoning tasks in which the congruence between currently-held beliefs and assumptions varies. Participants of younger and older age completed a series of syllogistic reasoning tasks in which two premises and one conclusion were presented and they were required to decide if the conclusion logically followed the premises. The belief load of premises was manipulated to be either congruent or incongruent with currently-held beliefs. Our whole-brain results showed that older adults recruited the hippocampus during the premise integration stage more than their younger counterparts. Functional connectivity using a hippocampal seed revealed that older, but not younger, adults recruited a hippocampal network that included anterior cingulate and inferior frontal regions when premises were believable. Importantly, this network contributed to better performance in believable inferences, only in older adults group. Further analyses suggested that, in older adults group, the integrity of the left cingulum bundle was associated with the higher correct rejection of believable premises more than unbelievable ones. Using multimodal imaging, this study highlights the importance of the hippocampus during premise integration and supports the compensatory role of the hippocampal network during a logical reasoning task among older adults.

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