Children's Ability to Recognize Emotions From Partial and Complete Facial Expressions

The authors investigated children's ability to recognize emotions from the information available in the lower, middle, or upper face. School-age children were shown partial or complete facial expressions and asked to say whether they corresponded to a given emotion (anger, fear, surprise, or disgust). The results indicate that 5-year-olds were able to recognize fear, anger, and surprise from partial facial expressions. Fear was better recognized from the information located in the upper face than those located in the lower face. A similar pattern of results was found for anger, but only in girls. Recognition improved between 5 and 10 years old for surprise and anger, but not for fear and disgust.     

Symmetry brings an impression of familiarity but does not improve recognition memory

Studies have shown that symmetric stimuli are recognized better than asymmetric stimuli but evidence suggests that this advantage may result from a familiarity bias induced by symmetry. We used a classic episodic memory paradigm to test this bias and see if it truly accounts for the symmetry advantage. Subjects first encoded symmetric and asymmetric figures. During a subsequent recognition phase, they discriminated the encoded (old) figures from new intermixed figures. The recognition rate of old figures was higher with symmetric figures than asymmetric figures. However, the tendency to falsely recognize new figures was also higher when they were symmetric, meaning that the higher recognition rate for symmetric figures was artificially inflated by a response bias. Three other experiments further tested this finding and examined the influence of some variables (rotation in virtual 3D space, stimulus meaningfulness, and redundancy of information) on the bias. A fifth experiment with photo stimuli confirmed that the response bias also applies to objects that we regularly encounter in everyday life. In conclusion, our results show that symmetry does not enhance mnemonic processes but instead induces a response bias leading individuals to judge such stimuli as having been seen.     

Functional magnetic resonance imaging study of Piaget's conservation-of-number task in preschool and school-age children: a neo-Piagetian approach

Jean Piaget’s theory is a central reference point in the study of logico-mathematical development in children. One of the most famous Piagetian tasks is number conservation. Failures and successes in this task reveal two fundamental stages in children’s thinking and judgment, shifting at approximately 7 years of age from visuospatial intuition to number conservation. In the current study, preschool children (nonconservers, 5-6 years of age) and school-age children (conservers, 9-10 years of age) were presented with Piaget’s conservation-of-number task and monitored by functional magnetic resonance imaging (fMRI). The cognitive change allowing children to access conservation was shown to be related to the neural contribution of a bilateral parietofrontal network involved in numerical and executive functions. These fMRI results highlight how the behavioral and cognitive stages Piaget formulated during the 20th century manifest in the brain with age.     

Visual memory and visual perception: when memory improves visual search

This study examined the relationship between memory and perception in order to identify the influence of a memory dimension in perceptual processing. Our aim was to determine whether the variation of typical size between items (i.e., the size in real life) affects visual search. In two experiments, the congruency between typical size difference and perceptual size difference was manipulated in a visual search task. We observed that congruency between the typical and perceptual size differences decreased reaction times in the visual search (Exp. 1), and noncongruency between these two differences increased reaction times in the visual search (Exp. 2). We argue that these results highlight that memory and perception share some resources and reveal the intervention of typical size difference on the computation of the perceptual size difference.     

The influence of contour fragmentation on recognition memory: an event-related potential study

The present study was carried out to examine how the event-related potentials to fragmentation predict recognition success. Stimuli were abstract meaningless figures that were either complete or fragmented to various extents but still recoverable. Stimuli were first encoded as part of a symmetry discrimination task. In a subsequent recognition phase, encoded stimuli were presented complete along with never presented stimuli and participants performed an old/new discrimination task. Fragmentation stimuli elicited more negative ERPs than complete figures over the frontal, central and parietal areas between 180 and 260 ms, and over the occipito-temporal areas between 220 and 340 ms. Only this latter effect was modulated as a function of whether stimuli were recognized or not during the recognition phase of the memory test. More specifically, the effect occurred for stimuli that were later forgotten and was absent for stimuli that were later recognized. This ERP to fragmentation, the occipito-temporal N(frag), possibly reflects the brain response to encoding difficulty, and is thus predictive of recognition performance.     

An fMRI investigation of a novel analogue to the Trail-Making Test

The Trail-Making Test (TMT) is a widely used neuropsychological measure that assesses visuomotor abilities and cognitive flexibility. For the TMT-A condition participants are required to locate and connect numbers (i.e. 1-2-3…) while in the TMT-B condition participants perform the set-shifting task of locating and connecting numbers and letters (i.e. 1-A-2-B…). The TMT-B condition has shown impairments in many clinical populations, particularly schizophrenia patients, but the neurobiological underpinning of the task can be difficult to discern given pragmatic obstacles in adapting the task for neuroimaging. In a behavioural testing experiment we demonstrated a close correspondence between performance on the standard TMT and a novel, computer programmed adaptation of the TMT (pcTMT). The pcTMT was designed for functional magnetic resonance imaging (fMRI) administration and neuroimaging data for this task were obtained in. A whole brain analysis revealed significantly greater activation during the pcTMT-B relative to the pcTMT-A in right inferior/middle frontal cortices, right precentral gyrus, left angular gyrus/left middle temporal gyrus. These results identify the regions that most likely underlie cognitive flexibility during the TMT and are candidate regions underlying the impairment of groups with poor set-shifting abilities.     

Perceived psychosocial benefits associated with perceived restorative potential of wilderness river-rafting trips

Analysis of the restorative experiences and psychosocial benefits of wilderness river rafting trips of varying difficulty with 186 Canadian participants of different ages supported the restorative potential of natural settings for all age groups as measured by the Perceived Restorativeness Scale. The two-factor structure (General Restorativeness and Coherence) was confirmed. Significant associations were found between scores on the General Restorative subscale and perceived psychosocial benefits (relaxation, nature appreciation or kinship, and physical fitness or achievement) and positive affect. However, the findings associated with the Coherence subscale were not conclusive.     

Anterior but not intralaminar thalamic nuclei support allocentric spatial memory

Medial thalamic damage is a common cause of severe memory disruption in humans. Both the anterior thalamic nuclei (ATN) and the intralaminar thalamic nuclei (ILN) have been suggested as primary sites of diencephalic injury underlying learning and memory deficits, but their respective roles have yet to be resolved. The present study explicitly compared two spatial memory tasks in male PVGc hooded rats with selective neurotoxic lesions to either (1) the ATN or (2) the rostral ILN (and adjacent lateral mediodorsal thalamic nuclei; ILN/LT lesions). As predicted, the ATN group, but not the ILN/LT group, exhibited clear deficits in the Morris water maze task for the initial acquisition of a fixed hidden platform and its reversal to a new position. The second task examined acquisition of egocentric spatial reference memory for a left or right body turn, using any three arms in an 8-arm water maze on any given trial; contrary to predictions, both lesion groups performed as well as the Sham group. The lack of deficits in ILN/LT rats on this second task contrasted with previous findings reporting a detrimental effect of ILN/LT lesions on egocentric working memory. The clear dissociation between the influence of ATN and ILN/LT lesions with respect to allocentric spatial reference memory in the Morris maze emphasizes that caution is required when interpreting the effects of non-ATN thalamic lesions on spatial memory when the lesions encroach substantial areas of the adjacent ATN region.     

Wittgenstein and Brouwer

In this paper, I present a summary of the philosophical relationship betweenWittgenstein and Brouwer, taking as my point of departure Brouwer's lecture onMarch 10, 1928 in Vienna. I argue that Wittgenstein having at that stage not doneserious philosophical work for years, if one is to understand the impact of thatlecture on him, it is better to compare its content with the remarks on logics andmathematics in the Tractactus. I thus show that Wittgenstein's position, in theTractactus, was already quite close to Brouwer's and that the points of divergence are the basis to Wittgenstein's later criticisms of intuitionism. Among the topics of comparison are the role of intuition in mathematics, rule following, choice sequences, the Law of Excluded Middle, and the primacy of arithmetic over logic.     

Short-term memory and time estimation: beyond the 2-second "critical" value.

We showed previously that when time intervals around two seconds (s) are reproduced concurrently with a memory task, intervals are positively related to duration of memory processing. However, some data in research on timing as well as in memory research suggest that 2 s might be a critical duration beyond which different mechanisms or structures would support performance. This implies that the interference observed between memory processing and 2-s productions could be specific to these durations, and would not be obtained with longer durations. In this experiment, intervals ranging from 1.85 to 6.45 s were reproduced by participants, who were searching simultaneously for a memory probe. At all durations, reproductions were positively related to memory set size. These findings have implications with regards to previous research indicating a discontinuity around 2-3 s in time perception. They suggest in particular that the role of memory is similar in reproduction of durations around 2 s and of longer durations.