It is more difficult for reasoners to detect that the letter-number pair H7 verifies the conditional rule If there is not a T then there is not a 4 than to detect that it verifies the rule If there is an H then there is a 7. In prior work [Prado, J., & Noveck, I. A. (2007). Overcoming perceptual features in logical reasoning: a parametric functional magnetic resonance imaging study. Journal of Cognitive Neuroscience 19(4), 642-657], we argued that this difficulty was due to mismatching effects, i.e. perceptual mismatches that arise when the items mentioned in the rule (e.g. T and 4) mismatch those presented in the test-pair (H and 7). The present study aimed to test this claim directly by recording ERPs while participants evaluated conditional rules in the presence or absence of mismatches. We found that mismatches, not only trigger a frontocentral N2 (an ERP known to be related to perceptual mismatch) but that they, parametrically modulate its amplitude (e.g. two mismatches prompt a greater N2 than one). Our results indicate that the main role of negations in conditional rules is to focus attention on the negated constituent but also suggest that there is some inter-individual differences in the way participants apprehend such negations, as indicated by a correlation between N2 amplitude and participants' reaction times. Overall, these findings emphasize how overcoming perceptual features plays a role in the mismatching effect and extend the mismatch-related effects of the N2 into a reasoning task.

Little is known about how peers' mere presence may, in itself, affect academic learning and achievement. The present study addresses this issue by exploring whether and how the presence of a familiar peer affects performance in a task assessing basic numeracy and literacy skills: numerosity and phonological comparisons. We tested 99 fourth-graders either alone or with a classmate. Ninety-seven college-aged young adults were also tested on the same task, either alone or with a familiar peer. Peer presence yielded a reaction time (RT) speedup in children, and this social facilitation was at least as important as that seen in adults. RT distribution analyses indicated that the presence of a familiar peer promotes the emergence of adult-like features in children. This included shorter and less variable reaction times (confirmed by an ex-Gaussian analysis), increased use of an optimal response strategy, and, based on Ratcliff's diffusion model, speeded up nondecision (memory and/or motor) processes. Peer presence thus allowed children to at least narrow (for demanding phonological comparisons), and at best, virtually fill in (for unchallenging numerosity comparisons) the developmental gap separating them from adult levels of performance. These findings confirm the influence of peer presence on skills relevant to education and lay the groundwork for exploring how the brain mechanisms mediating this fundamental social influence evolve during development.

Deductive reasoning is traditionally viewed as a unitary process involving either rule-based or visuo-spatial mechanisms. However, there is a disagreement in the neuroimaging literature on whether the data support one alternative over the other. Here we test the hypothesis that discrepancies in the literature result from the reasoning materials themselves. Using functional magnetic resonance imaging, we measure brain activity of participants while they integrate the premises of conditional arguments (primarily Modus Tollens: If P then Q; not-Q) and Relational Syllogisms (i.e., linear arguments of the sort P is to the left of Q; Q is to the left of R). We find that reasoning with Modus Tollens activates the left inferior frontal gyrus to a greater extent than the Relational Syllogisms. In contrast, the Relational Syllogisms engage the right temporo-parieto-occipital junction more than conditional arguments. This suggests that conditional reasoning relies more on so-called syntactic processes than relational reasoning, while relational reasoning may rely on visuo-spatial processes and mental imagery more than conditional reasoning. This investigative approach, together with its results, clarifies some apparently inconsistent findings in this literature by showing that the nature of the logical argument, whether it is relational or conditional, determines which neural system is engaged.

Although variations of response time (RT) within a particular experimental condition are typically ignored, they may sometimes reflect meaningful changes in the efficiency of cognitive and neural processes. In the present study, we investigated whether trial-by-trial variations of response time (RT) in a cross-modal selective attention task were associated with variations of functional connectivity between brain regions that are thought to underlie attention. Sixteen healthy young adults performed an audiovisual selective attention task, which involved attending to a relevant visual letter while ignoring an irrelevant auditory letter, as we recorded their brain activity using functional magnetic resonance imaging (fMRI). In line with predictions, variations of RT were associated with variations of functional connectivity between the anterior cingulate cortex and various other brain regions that are posited to underlie attentional control, such as the right dorsolateral prefrontal cortex and bilateral regions of the posterior parietal cortex. They were also linked to variations of functional connectivity between anatomically early and anatomically late regions of the relevant-modality visual cortex whose communication is thought to be modulated by attentional control processes. By revealing that variations of RT in a selective attention task are linked to variations of functional connectivity in the attentional network, the present findings suggest that variations of attention may contribute to trial-by-trial fluctuations of behavioral performance.

According to the default-mode interference hypothesis, suboptimal performance in tasks requiring selective attention occurs when off-task processing (e.g., mind wandering) supported by default-mode regions interferes with on-task processing (e.g., attention) enabled by task-positive regions. In the present functional MRI study, we therefore investigated whether suboptimal performance in a selective attention task was linked to heightened interactions between a key default-mode region (the posterior cingulate cortex; PCC) and a key task-positive region (the left dorsolateral prefrontal cortex; DLPFC). We also investigated whether heightened interactions between the PCC and the left DLPFC were linked to enhanced future performance, consistent with prior data suggesting that such interactions index adaptive changes to the cognitive system. In line with both of these predictions, increases of current-trial functional connectivity between the PCC and the left DLPFC were linked to increases of response time in the current trial (i.e., suboptimal performance), but to decreases of response time in the next trial (i.e., enhanced performance). This double dissociation provides novel support for the default-mode interference hypothesis. Moreover, it suggests the possibility that, in at least some cases, default-mode interference indexes processes that optimize future performance.

It is now well established that communicators interpret others' mental states through what has been called "Theory of Mind" (ToM). From a linguistic-pragmatics perspective, this mentalizing ability is considered critical because it is assumed that the linguistic code in all utterances underdetermines the speaker's meaning, leaving a vital role for ToM to fill the gap. From a neuroscience perspective, understanding others' intentions has been shown to activate a neural ToM network that includes the right and left temporal parietal junction (rTPJ, lTPJ), the medial prefrontal cortex (MPFC) and the precuneus (PC). Surprisingly, however, there are no studies - to our knowledge - that aim to uncover a direct, on-line link between language processing and ToM through neuroimaging. This is why we focus on verbal irony, an obviously pragmatic phenomenon that compels a listener to detect the speaker's (dissociated, mocking) attitude (Wilson, 2009). In the present fMRI investigation, we compare participants' comprehension of 18 target sentences as contexts make them either ironic or literal. Consider an opera singer who tells her interlocutor: "Tonight we gave a superb performance!" when the performance in question was clearly awful (making the statement ironic) or very good (making the statement literal). We demonstrate that the ToM network becomes active while a participant is understanding verbal irony. Moreover, we demonstrate - through Psychophysiological Interactions (PPI) analyses - that ToM activity is directly linked with language comprehension processes. The paradigm, its predictions, and the reported results contrast dramatically with those from seven prior fMRI studies on irony.

Variations of response time (RT) in selective attention tasks are often associated with variations of activity and functional connectivity in sensory cortices that process relevant stimuli. Here, we investigated whether such relationships are influenced by spatial attention. To investigate this hypothesis, we asked fourteen healthy adults to perform a covert spatial attention task, which made use of bilateral stimulus displays, while we recorded their brain activity using functional magnetic resonance imaging (fMRI). As expected, activity in the middle occipital gyrus increased when spatial attention was directed to the contralateral (versus the ipsilateral) visual field. Surprisingly, variations of RT were not associated with variations in the magnitude of this attentional enhancement. As predicted, however, they were linked to opposing variations of functional connectivity between middle occipital regions contralateral (but not ispilateral) to the attended visual field and the left fusiform gyrus, which is thought to figure prominently in the perceptual processing of visually presented letters. These findings suggest that trial-by-trial variations of RT reflect, at least partially, trial-by-trial variations in the extent to which spatial attention enhances functional connectivity between sensory regions that process relevant stimuli.

To enable unexpected shifts of covert visual spatial attention, a ventral attention network is thought to dampen activity in a dorsal attention network that maintains the current focus of attention. However, direct evidence to support this view is scarce. In the present study, we investigated this hypothesis by asking healthy young adults to perform a covert visual spatial attention task while their brain activity was recorded with functional magnetic resonance imaging (fMRI). In each trial, participants discriminated the orientation of a target-colored letter in the cued visual field (valid trials) or, occasionally, in the uncued visual field (invalid trials). Consistent with prior work, the ventral attention network was more active in invalid trials than in valid trials. Most importantly, functional connectivity analyses revealed that an increase of activity in the right inferior frontal gyrus (a key region of the ventral attention network) was linked to smaller increases of activity in (a) the right inferior parietal lobe (a key region of the dorsal attention network) and (b) the left dorsolateral prefrontal cortex and dorsal anterior cingulate cortex (other regions enabling the control of attention) in invalid trials, relative to valid trials. These findings provide novel support for the view that key regions of the ventral attention network help to enable unexpected shifts of covert visual spatial attention by dampening activity in brain regions that participate in maintaining the current focus of attention.

Scientific and mathematical thinking relies on the ability to evaluate whether conclusions drawn from conditional (if-then) arguments are logically valid. Yet, the neural development of this ability -- termed deductive reasoning -- is largely unknown. Here we aimed to identify the neural mechanisms that underlie the emergence of deductive reasoning with conditional rules in children. We further tested whether these mechanisms have their roots in the neural mechanisms involved in judging the likelihood of conclusions. In a functional Magnetic Resonance Imaging (fMRI) scanner, 8- to 13-year-olds were presented with causal conditional problems such as "If a baby is hungry then he will start crying; The baby is crying; Is the baby hungry?". In Validity trials, children were asked to indicate whether the conclusion followed out of necessity from the premises. In Likelihood trials, they indicated the degree of likelihood of the conclusion. We found that children who made accurate judgments of logical validity (as compared to those who did not) exhibited enhanced activity in left and medial frontal regions. In contrast, differences in likelihood ratings between children were related to differences of activity in right frontal and bilateral parietal regions. There was no overlap between the brain regions underlying validity and likelihood judgments. Therefore, our results suggest that the ability to evaluate the logical validity of conditional arguments emerges from brain mechanisms that qualitatively differ from those involved in evaluating the likelihood of these arguments in children.

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.