Levels of conflict in reasoning modulate right lateral prefrontal cortex

Dual-Process Theory of Thought and Inhibitory Control: An ALE Meta-Analysis

The dual-process theory of thought rests on the co-existence of two different thinking modalities: a quick, automatic, and associative process opposed to a slow, thoughtful, and deliberative process. The increasing interest in determining the neural foundation of the dual-process distinction has yielded mixed results, also given the difficulty of applying the fMRI standard approach to tasks usually employed in the cognitive literature. We report an activation likelihood estimation (ALE) meta-analysis to investigate the neural foundation of the dual-process theory of thought. Eligible studies allowed for the identification of cerebral areas associated with dual-process theory-based tasks without differentiating between fast and slow thinking. The ALE algorithm converged on the medial frontal cortex, superior frontal cortex, anterior cingulate cortex, insula, and left inferior frontal gyrus. These structures partially overlap with the cerebral areas recurrently reported in the literature about the neural basis of the dual-process distinction, where the PARCS theory-based interpretation emphasizes the role of the right inferior gyrus. The results confirm the potential (but still almost unexplored) common ground between the dual-process literature and the cognitive control literature.

A calculus of probability or belief? Neural underpinnings of social decision-making in a card game

For decades, the prefrontal cortex (PFC) has been the focus of social neuroscience research, specifically regarding its role in competitive social decision-making. However, the distinct contributions of PFC subregions when making strategic decisions involving multiple types of information (social, non-social, and mixed information) remain unclear. This study investigates decision-making strategies (pure probability calculation vs. mentalizing) and their neural representations using functional near-infrared spectroscopy (fNIRS) data collected during a two-person card game. We observed individual differences in information processing strategy, indicating that some participants relied more on probability than others. Overall, the use of pure probability decreased over time in favor of other types of information (e.g., mixed information), with this effect being more pronounced within-round trials than across rounds. In the brain, (1) the lateral PFC activates when decisions are driven by probability calculations; (2) the right lateral PFC responds to trial difficulty; and (3) the anterior medial PFC is engaged when decision-making involves mentalizing. Furthermore, neural synchrony, which reflects the real-time interplay between individuals' cognitive processes, did not consistently contribute to correct decisions and fluctuated throughout the experiment, suggesting a hierarchical mentalizing mechanism at work.

Geometric microstructural damage of white matter with functional compensation in post-stroke

BACKGROUND AND PURPOSE

Subcortical ischemic stroke usually leads to the geometric microstructural changes in the orientation of peri-infarct white matter fiber. We conducted the study to determine the microstructural changes in the white matter fiber orientation in post stroke patients with and without cognitive impairment (PSCI, NPSCI), and to investigate the impact of peri-infarct white matter damage on the morphology and functional connectivity of their projective cerebral regions.

METHODS

A novel mathematical framework called Director Field Analysis (DFA) was applied to study the microstructural changes in the orientation of white matter fiber in PSCI (n = 23), NPSCI (n = 17), and cognitively normal (CN, n = 29) individuals.

RESULTS

PSCI patients had extensive abnormalities in the orientation of white matter fiber in the corpus callosum, bilateral internal capsule, external capsule, forceps major, forceps minor, and corticospinal tract in comparison with NPSCI and CN. NPSCI patients also showed significant increases in bend and twist of white matter fiber orientation in the internal capsule in comparison with CN. Seed-based functional connectivity analysis showed that peri-infarct white matter deficits indicate a significant impact on functional connectivity with related cortical regions, suggesting the coexistence of impairment and compensation in post-stroke. In addition, these peri-infarct white matter damages and abnormal functional connectivity were significantly correlated with cognitive scores. Machine learning model also indicated that these changes in white matter fiber orientation and functional connectivity can predict the cognitive status in post-stroke.

CONCLUSIONS

Post-stroke patients experienced pathological damage in the orientation of peri-infarct white matter fiber. The peri-infarct white matter damage may further induce the abnormal functional connectivity in projective cerebral regions. These degenerations of peri-infarct white matter fiber and associated functional connectivity changes may mediate the cognitive impairment in post-stroke.

Can a fast thinker be a good thinker? The neural correlates of base-rate neglect measured using a two-response paradigm

Traditionally, it has been assumed that logical thinking requires deliberation. However, people can also make logical responses quickly, exhibiting logical intuitions. We examined the neural correlates of logical intuitions by administering base rate problems during fMRI scanning using a two-response paradigm where participants first responded quickly and then reflectively to problems that did or did not pit a normative response against an intuitively-cued stereotypical response (i.e., conflict vs. non-conflict problems). As predicted, participants were less likely to make judgments in accordance with base rates on conflict problems. Critically, in only 4% of cases did longer deliberation change an initially biased response to a normatively correct response. The fMRI data revealed that intuitively-made initial biased judgments nevertheless activate regions typically involved in cognitive control, executive functions and attention, including anterior, inferior, middle and superior frontal cortex, suggesting that even when errors are made, there might be very early awareness of conflict.

Age-related differences in structural and functional prefrontal networks during a logical reasoning task

In logical reasoning, difficulties in inhibition of currently-held beliefs may lead to unwarranted conclusions, known as belief bias. Aging is associated with difficulties in inhibitory control, which may lead to deficits in inhibition of currently-held beliefs. No study to date, however, has investigated the underlying neural substrates of age-related differences in logical reasoning and the impact of belief load. The aim of the present study was to delineate age differences in brain activity during a syllogistic logical reasoning task while the believability load of logical inferences was manipulated. Twenty-nine, healthy, younger and thirty, healthy, older adults (males and females) completed a functional magnetic resonance imaging experiment in which they were asked to determine the logical validity of conclusions. Unlike younger adults, older adults engaged a large-scale network including anterior cingulate cortex and inferior frontal gyrus during conclusion stage. Our functional connectivity results suggest that while older adults engaged the anterior cingulate network to overcome their intuitive responses for believable inferences, the inferior frontal gyrus network contributed to higher control over responses during both believable and unbelievable conditions. Our functional results were further supported by structure-function-behavior analyses indicating the importance of cingulum bundle and uncinate fasciculus integrity in rejection of believable statements. These novel findings lend evidence for age-related differences in belief bias, with potentially important implications for decision making where currently-held beliefs and given assumptions are in conflict.

Deductive-reasoning brain networks: A coordinate-based meta-analysis of the neural signatures in deductive reasoning

OBJECTIVE

Deductive reasoning is a complex and poorly understood concept in the field of psychology. Many cognitive neuroscience studies have been published on deductive reasoning but have yielded inconsistent findings.

METHODS

In this study, we analyzed collected data from 38 articles using a recently proposed activation likelihood estimation (ALE) approach and used conjunction analysis to better determine the intersection of the results of meta-analyses.

RESULTS

First, the left hemispheres in the inferior parietal lobule (Brodmann area 40 [BA40]), middle frontal gyrus (BA6), medial frontal gyrus (BA8), inferior frontal gyrus (BA45/46), caudate, and insula (BA47) were revealed to be significant brain regions via simple-effect analysis (deductive reasoning versus baseline). Furthermore, IFG, insula, and cingulate (the key neural hubs of the cingulo-opercular network) were highlighted in overlapped functional connectivity maps.

CONCLUSION

The findings of the current study are consistent with the view that deductive reasoning requires a succession of stages, which included decoding of linguistic information, conversion and correction of rules, and transformation of inferential results into conclusive outputs, all of which are putatively processed via a distributed network of brain regions encompassing frontal/parietal cortices, as well as the caudate and other subcortical structures, which suggested that in the process of deductive reasoning, the coding and integration of premise information is indispensable, and it is also crucial to the execution and monitoring of the cognitive processing of reasoning.

The neural bases of argumentative reasoning

Most reasoning tasks used in behavioral and neuroimaging studies are abstract, triggering slow, effortful processes. By contrast, most of everyday life reasoning is fast and effortless, as when we exchange arguments in conversation. Recent behavioral studies have shown that reasoning tasks with the same underlying logic can be solved much more easily if they are embedded in an argumentative context. In the present article, we study the neural bases of this type of everyday, argumentative reasoning. Such reasoning is both a social and a metarepresentational process, suggesting it should share some mechanisms, and thus some neural bases, with other social, metarepresentational process such as pragmatics, metacognition, or theory of mind. To isolate the neural bases of argumentative reasoning, we measured fMRI activity of participants who read the same statement presented either as the conclusion of an argument, or as an assertion. We found that conclusions of arguments, compared to assertions, were associated with greater activity in a region of the medial prefrontal cortex that was identified in quantitative meta-analyses of studies on theory of mind. This study shows that it is possible to use more ecologically valid tasks to study the neural bases of reasoning, and that using such tasks might point to different neural bases than those observed with the more abstract and artificial tasks typically used in the neuroscience of reasoning. Specifically, we speculate that reasoning in an argumentative context might rely on mechanisms supporting metarepresentational processes in the medial prefrontal cortex.

Neurocognitive processes underlying heuristic and normative probability judgments

Judging two events in combination (A&B) as more probable than one of the events (A) is known as a conjunction fallacy. According to dual-process explanations of human judgment and decision making, the fallacy is due to the application of a heuristic, associative cognitive process. Avoiding the fallacy has been suggested to require the recruitment of a separate process that can apply normative rules. We investigated these assumptions using functional magnetic resonance imaging (fMRI) during conjunction tasks. Judgments, whether correct or not, engaged a network of brain regions identical to that engaged during similarity judgments. Avoidance of the conjunction fallacy additionally, and uniquely, involved a fronto-parietal network previously linked to supervisory, analytic control processes. The results lend credibility to the idea that incorrect probability judgments are the result of a representativeness heuristic that requires additional neurocognitive resources to avoid.

Patients with Lesions to Left Prefrontal Cortex (BA 9 and BA 10) Have Less Entrenched Beliefs and Are More Skeptical Reasoners

The effect of prior beliefs on reasoning and decision-making is a robust, poorly understood phenomenon, exhibiting considerable individual variation. Neuroimaging studies widely show the involvement of the left pFC in reasoning involving beliefs. However, little patient data exist to speak to the necessity and role of the left pFC in belief-based inference. To address this shortcoming, we tested 102 patients with unilateral focal penetrating traumatic brain injuries and 49 matched controls. Participants provided plausibility ratings (plausible/implausible) to simple inductive arguments and (separately) strength of believability ratings of the conclusion to those same arguments. A voxel-based lesion symptom mapping analysis identified 10 patients, all with lesions to the left pFC (BA 9 and BA 10) as rating significantly fewer arguments with highly believable conclusions as "plausible," compared with all other patients. Subsequent analyses, incorporating the right hemisphere homologue of these patients (n = 12) and normal controls (n = 24), revealed patients with lesions to left pFC found fewer arguments plausible in the high believable than either of these groups, and there was no difference in the behavioral scores of the right pFC patients and normal controls. Further analysis, utilizing the belief ratings as the dependent measure, revealed a Group × Belief Rating interaction, with left pFC patients having less intense beliefs about the conclusions of moderately believable and highly believable arguments. We interpreted these results to indicate that lesions to left pFC (BA 9, BA 10) increase incredulity and make these patients more skeptical reasoners. The former can partially, but not fully, explain the latter. The other relevant factor may be that unilateral left pFC lesions disrupt hemispheric equilibrium and allow for an increased inhibitory role of the right pFC. We speculate that individual differences in belief bias in reasoning in the normal population may be a function of individual differences in the left and right pFC interactional dynamics.

Dual-process theory, conflict processing, and delusional belief

Many reasoning biases that may contribute to delusion formation and/or maintenance are common in healthy individuals. Research indicating that reasoning in the general population proceeds via analytic processes (which depend upon working memory and support hypothetical thought) and intuitive processes (which are autonomous and independent of working memory) may therefore help uncover the source of these biases. Consistent with this possibility, recent studies imply that impaired conflict processing might reduce engagement in analytic reasoning, thereby producing reasoning biases and promoting delusions in individuals with schizophrenia. Progress toward understanding this potential pathway to delusions is currently impeded by ambiguity about whether any of these deficits or biases is necessary or sufficient for the formation and maintenance of delusions. Resolving this ambiguity requires consideration of whether particular cognitive deficits or biases in this putative pathway have causal primacy over other processes that may also participate in the causation of delusions. Accordingly, the present manuscript critically evaluates whether impaired conflict processing is the primary initiating deficit in the generation of reasoning biases that may promote the development and/or maintenance of delusions. Suggestions for future research that may elucidate mechanistic pathways by which reasoning deficits might engender and maintain delusions are subsequently offered.

Developmental frontal brain activation differences in overcoming heuristic bias

Since reasoning is often biased by intuitive heuristics, the development of sound reasoning has long been postulated to depend on successful bias monitoring and inhibition. The present fMRI study aimed to identify neural correlates of developmental changes in these processes. A group of adults and young adolescents were presented with ratio-bias problems in which an intuitively cued heuristic response could be incongruent (conflict item) or congruent (no-conflict item) with the correct response. Results showed that successfully avoiding biased responding on conflict items across both age groups was associated with increased activation in Anterior Cingulate Cortex (ACC) and the right Lateral Prefrontal Cortex (LPFC) regions of interest. Critically, the right LPFC activation decreased with age. Biased responding did not result in right LPFC or ACC modulation and failed to show any developmental activation changes. We discuss implications for ongoing debates on the nature of heuristic bias and its development.

Hemispheric asymmetry in the prefrontal cortex for complex cognition

With the exception of language, hemispheric asymmetry has not historically been an important issue in the frontal lobe literature. Data generated over the past 20 years is forcing a reconsideration of this position. There is now considerable evidence to suggest that the left prefrontal cortex is an inference engine that automatically makes simple conceptual, logical, and causal connections to fill in missing information and eliminate uncertainty or indeterminacy. This is a fine-tuning of the "left hemisphere interpreter" account from the callosotomy patient literature. What is new is an understanding of the important contributions of the right prefrontal cortex to formal logical inference, conflict detection, and indeterminacy tolerance and maintenance. This chapter articulates these claims and reviews the data on which they are based. The chapter concludes by speculating that the inference capabilities of the left prefrontal cortex are built into the very fabric of language and can be accounted for by the left hemisphere dominance for language. The roles of the right PFC require multiple mechanisms for explanation. Its role in formal inference may be a function of its visual-spatial processing capabilities. Its role in conflict detection may be explained as a system for checking for consistency between existing beliefs and new information coming into the system and inferences drawn from beliefs and/or new information. There are at least three possible mechanisms to account for its role in indeterminacy tolerance. First, it could contain a representational system with properties very different from those of language, and an accompanying inference engine. Second, it could just contain this different representational system, and the information is at some point passed back to the left prefrontal cortex for inference. Third, the role of the right prefrontal cortex may be largely preventative. That is, it doesn't provide alternative representational and inference capabilities but simply prevents the left prefrontal cortex from settling on initial, local inferences. The current data do not allow differentiating between these possibilities. Successful real-world functioning requires the participation of both hemispheres.

Developmental grey matter changes in superior parietal cortex accompany improved transitive reasoning

The neural basis of developmental changes in transitive reasoning in parietal regions was examined, using voxel-based morphometry. Young adolescents and adults performed a transitive reasoning task, subsequent to undergoing anatomical magnetic resonance imaging (MRI) brain scans. Behaviorally, adults reasoned more accurately than did the young adolescents. Neural results showed (i) less grey matter density in superior parietal cortex in the adults than in the young adolescents, possibly due to a developmental period of synaptic pruning; (ii) improved performance in the reasoning task was negatively correlated with grey matter density in superior parietal cortex in the adolescents, but not in the adult group; and (iii) the latter results were driven by the more difficult trials, requiring greater spatial manipulation. Taken together, the results support the idea that during development, regions in superior parietal cortex are fine-tuned, to support more robust spatial manipulation, resulting in greater accuracy and efficiency in transitive reasoning.

Hemispheric lateralization in reasoning

A growing body of evidence suggests that reasoning in humans relies on a number of related processes whose neural loci are largely lateralized to one hemisphere or the other. A recent review of this evidence concluded that the patterns of lateralization observed are organized according to two complementary tendencies. The left hemisphere attempts to reduce uncertainty by drawing inferences or creating explanations, even at the cost of ignoring conflicting evidence or generating implausible explanations. Conversely, the right hemisphere aims to reduce conflict by rejecting or refining explanations that are no longer tenable in the face of new evidence. In healthy adults, the hemispheres work together to achieve a balance between certainty and consistency, and a wealth of neuropsychological research supports the notion that upsetting this balance results in various failures in reasoning, including delusions. However, support for this model from the neuroimaging literature is mixed. Here, we examine the evidence for this framework from multiple research domains, including an activation likelihood estimation analysis of functional magnetic resonance imaging studies of reasoning. Our results suggest a need to either revise this model as it applies to healthy adults or to develop better tools for assessing lateralization in these individuals.

"Shall I compare thee": The neural basis of literary awareness, and its benefits to cognition

Functional magnetic resonance imaging (fMRI) was used to explore the neural and cognitive basis of literary awareness in 24 participants. The 2×2 design explored the capacity to process and derive meanings in complex poetic and prosaic texts that either did or did not require significant reappraisal during reading. Following this, participants rated each piece on its 'poeticness' and the extent to which it prompted a reappraisal of meaning during reading, providing subjective measures of poetic recognition and the need to reappraise meaning. The substantial shared variance between these 2 subjective measures provided a proxy measure of literary awareness, which was found to modulate activity in regions comprising the central executive and saliency networks. We suggest that enhanced literary awareness is related to increased flexibility of internal models of meaning, enhanced interoceptive awareness of change, and an enhanced capacity to reason about events. In addition, we found that the residual variance in the measure of poetic recognition modulated right dorsal caudate activity, which may be related to tolerance of uncertainty. These findings are consistent with evidence that relates reading to improved mental wellbeing.

What makes us think? A three-stage dual-process model of analytic engagement

The distinction between intuitive and analytic thinking is common in psychology. However, while often being quite clear on the characteristics of the two processes ('Type 1' processes are fast, autonomous, intuitive, etc. and 'Type 2' processes are slow, deliberative, analytic, etc.), dual-process theorists have been heavily criticized for being unclear on the factors that determine when an individual will think analytically or rely on their intuition. We address this issue by introducing a three-stage model that elucidates the bottom-up factors that cause individuals to engage Type 2 processing. According to the model, multiple Type 1 processes may be cued by a stimulus (Stage 1), leading to the potential for conflict detection (Stage 2). If successful, conflict detection leads to Type 2 processing (Stage 3), which may take the form of rationalization (i.e., the Type 1 output is verified post hoc) or decoupling (i.e., the Type 1 output is falsified). We tested key aspects of the model using a novel base-rate task where stereotypes and base-rate probabilities cued the same (non-conflict problems) or different (conflict problems) responses about group membership. Our results support two key predictions derived from the model: (1) conflict detection and decoupling are dissociable sources of Type 2 processing and (2) conflict detection sometimes fails. We argue that considering the potential stages of reasoning allows us to distinguish early (conflict detection) and late (decoupling) sources of analytic thought. Errors may occur at both stages and, as a consequence, bias arises from both conflict monitoring and decoupling failures.

Divergent hemispheric reasoning strategies: reducing uncertainty versus resolving inconsistency

Converging lines of evidence from diverse research domains suggest that the left and right hemispheres play distinct, yet complementary, roles in inferential reasoning. Here, we review research on split-brain patients, brain-damaged patients, delusional patients, and healthy individuals that suggests that the left hemisphere tends to create explanations, make inferences, and bridge gaps in information, while the right hemisphere tends to detect conflict, update beliefs, support mental set-shifts, and monitor and inhibit behavior. Based on this evidence, we propose that the left hemisphere specializes in creating hypotheses and representing causality, while the right hemisphere specializes in evaluating hypotheses, and rejecting those that are implausible or inconsistent with other evidence. In sum, we suggest that, in the domain of inferential reasoning, the left hemisphere strives to reduce uncertainty while the right hemisphere strives to resolve inconsistency. The hemispheres’ divergent inferential reasoning strategies may contribute to flexible, complex reasoning in the healthy brain, and disruption in these systems may explain reasoning deficits in the unhealthy brain.

Different neural systems contribute to semantic bias and conflict detection in the inclusion fallacy task

The inclusion fallacy is a phenomenon in which generalization from a specific premise category to a more general conclusion category is considered stronger than a generalization to a specific conclusion category nested within the more general set. Such inferences violate rational norms and are part of the reasoning fallacy literature that provides interesting tasks to explore cognitive and neural basis of reasoning. To explore the functional neuroanatomy of the inclusion fallacy, we used a 2 × 2 factorial design, with factors for quantification (explicit and implicit) and response (fallacious and non-fallacious). It was found that a left fronto-temporal system, along with a superior medial frontal system, was specifically activated in response to fallacious responses consistent with a semantic biasing of judgment explanation. A right fronto-parietal system was specifically recruited in response to detecting conflict associated with the heightened fallacy condition. These results are largely consistent with previous studies of reasoning fallacy and support a multiple systems model of reasoning.

Neural interaction between logical reasoning and pragmatic processing in narrative discourse

Logical connectives (e.g., or, if, and not) are central to everyday conversation, and the inferences they generate are made with little effort in pragmatically sound situations. In contrast, the neural substrates of logical inference-making have been studied exclusively in abstract tasks where pragmatic concerns are minimal. Here, we used fMRI in an innovative design that employed narratives to investigate the interaction between logical reasoning and pragmatic processing in natural discourse. Each narrative contained three premises followed by a statement. In Fully-deductive stories, the statement confirmed a conclusion that followed from two steps of disjunction-elimination (e.g., Xavier considers Thursday, Friday, or Saturday for inviting his girlfriend out; he removes Thursday before he rejects Saturday and declares "I will invite her out for Friday"). In Implicated-premise stories, an otherwise identical narrative included three premises that twice removed a single option from consideration (i.e., Xavier rejects Thursday for two different reasons). The conclusion therefore necessarily prompts an implication (i.e., Xavier must have removed Saturday from consideration as well). We report two main findings. First, conclusions of Implicated-premise stories are associated with more activity than conclusions of Fully-deductive stories in a bilateral frontoparietal system, suggesting that these regions play a role in inferring an implicated premise. Second, brain connectivity between these regions increases with pragmatic abilities when reading conclusions in Implicated-premise stories. These findings suggest that pragmatic processing interacts with logical inference-making when understanding arguments in narrative discourse.

The development of delusion revisited: a transdiagnostic framework

This study proposes a transdiagnostic framework for delusion development, analysing psychiatric (schizophrenia, bipolar disorder, major depressive disorder) and neurological disorders (stroke, and neurodegenerative diseases) in which delusions are predominant. Our aim is to identify a transdiagnostic core of neural and cognitive alterations associated with delusions across distinct clinical disorders. Reviewed empirical evidence suggests delusions are associated: on the neural level with changes in the ventromedial prefrontal cortex (vmPFC) networks, and on the neuropsychological level with dysfunction in the processes (generation of affective value, the construction of internal models of the world, and the reflection about Self and/or Other's mental states) that these network mediate. The concurrent aberration of all these processes could be critical for the clinical transition to a psychotic delusional state. In particular, delusions could become clinically manifest when (1) stimuli are attributed an aberrant affective salience, that (2) is explained by the patient within distorted explanatory internal models that (3) are poorly inhibited by cognitive control systems. This framework extends the two-factor account of delusion model and suggests that common neural mechanisms for the delusions in psychiatric and in neurological disorders.

Rationality and emotionality: serotonin transporter genotype influences reasoning bias

Reasoning often occurs under emotionally charged, opinion-laden circumstances. The belief-bias effect indexes the extent to which reasoning is based upon beliefs rather than logical structure. We examined whether emotional content increases this effect, particularly for adults genetically predisposed to be more emotionally reactive. SS/SL(G) carriers of the serotonin transporter genotype (5-HTTLPR) were less accurate selectively for evaluating emotional relational reasoning problems with belief-logic conflict relative to L(A)L(A) carriers. Trait anxiety was positively associated with emotional belief-bias, and the 5-HTTLPR genotype significantly accounted for the variance in this association. Thus, deductive reasoning, a higher cognitive ability, is sensitive to differences in emotionality rooted in serotonin neurotransmitter function.