Ensemble representations are often described as efficient tools when summarizing features of multiple similar objects as a group. However, it can sometimes be more useful not to compute a single summary description for all of the objects if they are substantially different, for example when they belong to entirely different categories. It was proposed that the visual system can efficiently use the distributional information of ensembles to decide whether simultaneously displayed items belong to single or several different categories. Here we directly tested how the feature distribution of items in a visual array affects an ability to discriminate individual items (Experiment 1) and sets (Experiments 2–3) when participants were instructed explicitly to categorize individual objects based on the median of size distribution. We varied the width (narrow or fat) as well as the shape (smooth or two-peaked) of distributions in order to manipulate the ease of ensemble extraction from the items. We found that observers unintentionally relied on the grand mean as a natural categorical boundary and that their categorization accuracy increased as a function of the size differences among individual items and a function of their separation from the grand mean. For ensembles drawn from two-peaked size distributions, participants showed better categorization performance. They were more accurate at judging within-category ensemble properties in other dimensions (centroid and orientation) and less biased by superset statistics. This finding corroborates the idea that the two-peaked feature distributions support the “segmentability” of spatially intermixed sets of objects. Our results emphasize important roles of ensemble statistics (mean, range, distribution shape) in explicit visual categorization.
Description: Visual working memory (VWM) is prone to interference from stored items competing for its limited capacity. These competitive interactions can arise from different sources. For example, one such source is poor item distinctiveness causing a failure to discriminate between items sharing common features. Another source of interference is imperfect binding, a problem of determining which of the remembered features belonged to which object or which item was in which location. In two experiments, we studied how the conceptual distinctiveness of real-world objects (i.e., whether the objects belong to the same or different basic categories) affects VWM for objects and object-location binding. In Experiment 1, we found that distinctiveness did not affect memory for object identities or for locations, but low-distinctive objects were more frequently reported at “swapped” locations that originally went with different objects. In Experiment 2 we found evidence that the effect of distinctiveness on the object-location swaps was due to the use of categorical information for binding. In particular, we found that observers swapped the location of a tested object with another object from the same category more frequently than with any of the objects from another category. This suggests that observers can use some coarse category-location information when objects are conceptually distinct. Taken together, our findings suggest that object distinction and object-location binding act upon different components of VWM.
When storing multiple objects in visual working memory, observers sometimes misattribute perceived features to incorrect locations or objects. These misattributions are called binding errors (or swaps) and have been previously demonstrated mostly in simple objects whose features are easy to encode independently and arbitrarily chosen, like colors and orientations. Here, we tested whether similar swaps can occur with real-world objects, where the connection between features is meaningful rather than arbitrary. In Experiments 1 and 2, observers were simultaneously shown four items from two object categories. Within a category, the two exemplars could be presented in either the same or different states (e.g., open/closed; full/empty). After a delay, both exemplars from one of the categories were probed, and participants had to recognize which exemplar went with which state. We found good memory for state information and exemplar information on their own, but a significant memory decrement for exemplar–state combinations, suggesting that binding was difficult for observers and swap errors occurred even for meaningful real-world objects. In Experiment 3, we used the same task, but in one-half of the trials, the locations of the exemplars were swapped at test. We found that there are more errors in general when the locations of exemplars were swapped. We concluded that the internal features of real-world objects are not perfectly bound in working memory, and location updates impair object and feature representations. Overall, we provide evidence that even real-world objects are not stored in an entirely unitized format in working memory.
Ensemble statistics are often thought of as a reliable impression of numerous items despite limited capacities to consciously represent each individual. However, whether all items equally contribute to ensemble summaries (e.g., mean) and whether they might be affected by known limited-capacity processes, such as focused attention, is still debated. We addressed these questions via a recently described “amplification effect,” a systematic bias of perceived mean (e.g., average size) towards the more salient “tail” of a feature distribution (e.g., larger items). In our experiments, observers adjusted the mean orientation of sets of items varying in set size. We made some of the items more salient or less salient by changing their size. While the whole orientation distribution was fixed, the more salient subset could be shifted relative to the set mean or differ in range. We measured the bias away from the set mean and the standard deviation (SD) of errors, as it is known to reflect the physical range from which ensemble information is sampled. We found that bias and SD changes followed the shifts and range changes in salient subsets, providing evidence for amplification. However, these changes were weaker than those expected from sampling only salient items, suggesting that less salient items were also sampled. Importantly, the SD decreased as a function of set size, which is only possible if the number of sampled elements increased with set size. Overall, we conclude that orientation summary statistics are sampled from an entire ensemble and modulated by the amplification effect of attention.
According to numerous studies observers can rapidly and precisely evaluate mean or range of the set. Recent studies have shown that the mean size estimated based on sizes of objects rescaled to their distances (Tiurina & Utochkin, 2019). In the current study, we directly tested this rescaling mechanism on the perception of range using binocular and monocular cues.
In Experiment 1, a sample set of circles with different angular sizes and in different apparent distances were stereoscopically presented. Participants had to adjust the range of the test set to match the range of the sample set. The main manipulation was the size-distance correlation for sample and test sets: in negative size-distance correlation, the apparent range had to decrease, while in positive correlation - increase. We found the highest underestimation in the condition with the negative sample correlation and positive test correlation, which could be explained only if ensemble summary statistics were estimated after the item's rescaling.
In Experiment 2, we used Ponzo-like illusion and spatial positions as a depth cue. Sets were presented with positive, negative or without size-distance correlation on a grey background or the background with Ponzo-like illusion. We found that the range was underestimated in negative correlation and overestimated in positive correlation.
Thus, items of ensemble could be automatically rescaled according to their distance, based on both binocular and monocular cues, and ensemble summary statistics estimation is based on perceived sizes.
Digital transformation of human mind is on the agenda in both cognitive and personality psychology. There is a number of approaches in cognitive science addressing the question how humans create culture, but less approaches address the issue of how culture transforms our ‘natural’ cognitive functions. One of such approaches, the cultural-historical psychology, was proposed almost a century ago by Vygotsky. This paper aims at demonstrating how Vygotskian framework, and his concepts of cultural mediation and the zone of proximal development in particular, could be used to understand cognitive development in the digital world. I argue that digital technologies transform the course of cognitive development as outlined in Vygotsky’s cultural-historical psychology. First, socialization is not internalization any more, as our cognitive functions become externalized again due to the use of new digital ‘tools of the mind’, in agreement with the Extended Cognition framework. Second, an adult doesn’t set the ‘zone of proximal development’ for a child any more, with this function being entrusted to digital devices, similarly to how the Material Engagement Theory treats evolution of the first prehistoric tools. I demonstrate that, whereas digital technologies challenge cultural-historical psychology, it might provide new insights into cognitive development in the digital context.
Spatial attention of people involved in a co-operative activity is often directed to the same objects in the environment. At the same time, one of the partners’ gaze redirection can be involved in controlling attention of others. It could be assumed that the degree of the gaze cueing effect, which has become a focus of growing research interest in recent decades, might be influenced by such social psychological factors as one’s attitude towards the partner and social distance between the partners. To test these assumptions, a virtual 3D environment was created, in which a modified version of the cueing paradigm by Posner et al. (1978) was implemented. An intergroup experimental design was used. For one group of participants, the anthropomorphic avatar was introduced in the instruction as a “virtual assistant”, for the other group, it was presented as a “virtual assessment specialist”. The avatar could provide valid and invalid gaze cues regarding the future target location. Both groups participated in two experimental sessions, in one session the distance between the participant and the avatar was 1.5 m (comfortable distance corresponding to the zone of formal social contacts) and in the other session the distance was 1 m (uncomfortable distance corresponding to the zone of personal contacts). The gaze cueing effect was observed through all experimental conditions in a virtual environment. However, it was more pronounced for the “assisting” set than for the “assessing” one. Interestingly, for the assisting set, the effect was asymmetric: the gain due to a valid cue turned out to be less pronounced than the delay in the response to a target after an invalid cue. For both conditions, the gaze cueing effect was more pronounced at a distance of 1 m between the participant and the avatar than at a distance of 1.5 m. The latter result could be associated either with the large angular dimensions of a gaze cue or with blurring of boundaries of the personal zone in the virtual environment. The results can be applied in the development of educational virtual environments.
The temporal dynamic characteristics of mood play an important role in various aspects of our lives, including our psychological health and well-being. It is assumed that individuals with high emotional intelligence (EI) are characterized by more positive and stable moods. However, most studies analyze how EI is related to emotional traits or momentary assessments of mood, hence not much is known about the relationship of EI to mood dynamics. The present study aimed at answering the following questions: How are dynamic characteristics of mood related to each other? To what extent are they independent? Which aspects of EI are related to particular characteristics of mood dynamics? Participants filled out an EI questionnaire and then reported their mood three times daily for two weeks. Mean mood scores calculated across all measurement points were regarded as static characteristics showing a mood background typical for the participant. Also, three dynamic characteristics of mood were calculated, namely variability, instability, and inertia. Mood variability and instability have been found to be very closely related to each other but not to inertia. Higher EI is related to more enduring mood states, i.e., higher mood inertia and a higher stability of the tension dimension of mood. Unlike previous studies that measured only static mood characteristics, no relationship between higher EI and positive mood have been found. Some aspects of EI were related to the inertia of negative and positive moods. The results show that experience sampling provides new insights on the role of EI in mood.
Knowledge of target features can guide attention in many conjunction searches in a top-down manner. For example, in search of a red vertical line among blue vertical and red horizontal lines, observers can guide attention toward all red items and all vertical items. In typical conjunction searches, distractors often form perceptually vivid, categorical groups of identical objects. This could favor the efficient search via guidance of attention to these “segmentable” groups. Can attention be guided if the distractors are not neatly segmentable (e.g., if colors vary continuously from red through purple to blue)? We tested search for conjunctions of color × orientation (Experiments 1, 3, 4, 5) or length × orientation (Experiment 2). In segmentable conditions, distractors could form two clear groups (e.g., blue steep and red flat). In non-segmentable conditions, distractors varied smoothly from red to blue and/or steep to flat; thus, discouraging grouping and increasing overall heterogeneity. We found that the efficiency of conjunction search was reasonably high and unaffected by segmentability. The same lack of segmentability had a detrimental effect on feature search (Experiment 4) and on conjunction search, if target information was limited to one feature (e.g., find the odd item in the red set, “subset search,” Experiment 3). Guidance in conjunction search may not require grouping and segmentation cues that are very important in other tasks like texture discrimination. Our results support an idea of simultaneous, parallel top-down guidance by multiple features and argue against models suggesting sequential guidance by each feature in turn.
Goldberg, the author of the “novelty-routinization” framework, suggested a new pair of cognitive styles for agent-centered decision-making (DM), context-dependency/independency (CD/CI), quantified by the Cognitive Bias Task (CBT) and supposedly reflecting functional brain hemispheric specialization. To date, there are only three lesion and activation neuroimaging studies on the CBT with the largest sample of 12 participants. The present study is the first to analyze whole-brain functional connectivity (FC) of the dorsolateral prefrontal cortex (DLPFC), involved in contextual agent-centered DM.
We compared whole-brain resting-state FC of the DLPFC between CD (n = 24) and CI (n = 22) healthy participants. Additionally, we investigated associations between CD/CI and different aspects of executive functions.
CD participants had stronger positive FC of the DLPFC with motor and visual regions; FC of the left DLPFC was more extensive. CI participants had stronger positive FC of the left DLPFC with right prefrontal and parietal-occipital areas and of the left and right DLPFC with ipsilateral cerebellar hemispheres. No sex differences were found. CD/CI had nonlinear associations with working memory.
The findings suggest that CD and CI are associated with different patterns of DLPFC FC. While CD is associated with FC between DLPFC and areas presumably involved in storing representations of current situation, CI is more likely to be associated with FC between DLPFC and right-lateralized associative regions, probably involved in the inhibition of the CD response and switching from processing of incoming perceptual information to creation of original response strategies.
Objective The dorsolateral prefrontal cortex (DLPFC) orchestrates other brain regions and plays a vital role for “the most uniquely human” executive functions (EFs), which are divided into distinct components. Components of EFs have been localized to different brain regions and at the same time the DLPFC was found to be involved in a majority of EF components. The possible mechanism of the DLPFC's contribution to EF components might be found in DLPFC functional connectivity (FC): this FC of the DLPFC with other brain regions contributes to different EF components. Method To explore the DLPFC FC contribution to different EFs, we used an integrative approach involving analysis of fMRI and neuropsychological assessment of EFs. Fifty healthy adults (27 females and 23 males, mean age 34.5 ± 16.6 years) underwent neuropsychological assessment of EFs as well as task-based and resting-state fMRI. Task-based fMRI was applied as a functional localizer for individually defined DLPFC ROIs that were further used for the FC seed-based correlation analysis of the resting-state data. Then we looked for associations between individual scores of different EF components and the whole-brain resting-state FC of the DLPFC. Results Resting-state correlates of DLPFC FC were revealed for three out of the seven EF components derived from an extensive neuropsychological assessment: inhibition, switching, and the verbal EF component. Conclusions Our study is the first to reveal the contribution of the DLPFC FC to several distinct EF components. The obtained results give insight into the brain mechanisms of EFs.
People can store thousands of real-world objects in visual long-term memory with high precision. But are these objects stored as unitary, bound entities, as often assumed, or as bundles of separable features? We tested this in several experiments. In the first series of studies, participants were instructed to remember specific exemplars of real-world objects presented in a particular state (e.g., open/closed, full/empty, etc.), and then were asked to recognize either which exemplars they had seen (e.g., I saw this coffee mug), or which exemplar-state conjunctions they had seen (e.g., I saw this coffee mug and it was full). Participants had a large number of within-category confusions, for example misremembering which states went with which exemplars, while simultaneously showing strong memory for the features themselves (e.g., which states they had seen, which exemplars they had seen). In a second series of studies, we found further evidence of independence: participants were very good at remembering which exemplars they had seen independently of whether these items were presented in a new or old state, but the same did not occur for features known to be truly holistically represented. Thus, we find through 2 lines of evidence that the features of real-world objects that support exemplar discrimination and state discrimination are not bound, suggesting visual objects are not inherently unitary entities in memory.
Prevailing theories of visual working memory assume that each encoded item is stored or forgotten as a separate unit independent from other items. Here, we show that items are not independent, and that the recalled orientation of an individual item is strongly influenced by the summary statistical representation of all items (ensemble representation). We find that not only is memory for an individual orientation substantially biased towards the mean orientation, but the precision of memory for an individual item also closely tracks the precision with which people store the mean orientation (which is, in turn, correlated with the physical range of orientations). Thus, individual items are reported more precisely when items on a trial are more similar. Moreover, the narrower the range of orientations present on a trial, the more participants appear to rely on the mean orientation as representative of all individuals. This can be observed not only when the range is carefully controlled, but also shown even in randomly generated, unstructured displays, and after accounting for the possibility of location-based ‘swap’ errors. Our results suggest that the information about a set of items is represented hierarchically, and that ensemble information can be an important source of information to constrain uncertain information about individuals.
Long-duration spaceflight causes widespread physiological changes, although its effect on brain structure remains poorly understood. In this work, we acquired diffusion magnetic resonance imaging to investigate alterations of white matter (WM), gray matter (GM), and cerebrospinal fluid (CSF) compositions in each voxel, before, shortly after, and 7 months after long-duration spaceflight. We found increased WM in the cerebellum after spaceflight, providing the first clear evidence of sensorimotor neuroplasticity. At the region of interest level, this increase persisted 7 months after return to Earth. We also observe a widespread redistribution of CSF, with concomitant changes in the voxel fractions of adjacent GM. We show that these GM changes are the result of morphological changes rather than net tissue loss, which remained unclear from previous studies. Our study provides evidence of spaceflight-induced neuroplasticity to adapt motor strategies in space and evidence of fluid shift– induced mechanical changes in the brain.
Despite the increasing popularity of neurofeedback, its mechanisms of action are still poorly understood. This study aims to describe the processes underlying implicit electroencephalographic neurofeedback. Fifty-two healthy volunteers were randomly assigned to a single session of infra-low frequency neurofeedback or sham neurofeedback, with electrodes over the right middle temporal gyrus and the right inferior parietal lobule. They observed a moving rocket, the speed of which was modulated by the waveform derived from a band-limited infra-low frequency filter. Immediately before and after the session, the participants underwent a resting-state fMRI. Network-based statistical analysis was applied, comparing post- vs. pre-session and real vs. sham neurofeedback conditions. As a result, two phenomena were observed. First, we described a brain circuit related to the implicit neurofeedback process itself, consisting of the lateral occipital cortex, right dorsolateral prefrontal cortex, left orbitofrontal cortex, right ventral striatum, and bilateral dorsal striatum. Second, we found increased connectivity between key regions of the salience, language, and visual networks, which is indicative of integration in sensory processing. Thus, it appears that a single session of implicit infra-low frequency electroencephalographic neurofeedback leads to significant changes in intrinsic brain connectivity.
Group problem solving is a prototypical complex collective intellectual activity. Psychological research provides compelling evidence that problem solving in groups is both qualitatively and quantitatively different from doing so alone. However, the question of whether individual and collective problem solving involve the same neural substrate has not yet been addressed, mainly due to methodological limitations. In the current study, functional magnetic resonance imaging was performed to compare brain activation when participants solved Raven-like matrix problems in a small group and individually. In the group condition, the participant in the scanner was able to discuss the problem with other team members using a special communication device. In the individual condition, the participant was required to think aloud while solving the problem in the silent presence of the other team members. Greater activation was found in several brain regions during group problem solving, including the medial prefrontal cortex; lateral parietal, cingulate, precuneus and retrosplenial cortices; frontal and temporal poles. These areas have been identified as potential components of the so-called “social brain” on the basis of research using offline judgments of material related to socializing. Therefore, this study demonstrated the actual involvement of these regions in real-time social interactions, such as group problem solving. However, further connectivity analysis revealed that the social brain components are co-activated, but do not increase their coupling during cooperation as would be suggested for a holistic network. We suggest that the social mode of the brain may be described instead as a re-configuration of connectivity between basic networks, and we found decreased connectivity between the language and salience networks in the group compared to the individual condition. A control experiment showed that the findings from the main experiment cannot be entirely accounted for by discourse comprehension. Thus, the study demonstrates affordances provided by the presented new technique for neuroimaging the “group mind,” implementing the single-brain version of the secondperson neuroscience approach.
The article presents pilot data from a study conducted as part of a large project investigating the impact of socialization on child development supported by a Grant from the Government of the Russian Federation (№14.Z50.31.0027, PI: Grigorenko). The purpose of the study was to investigate indicators of psychological, social and emotional well-being in adults with experience of institutionalization in comparison with peers who grew up in biological families. We used scales from the Achenbach System of Empirically Based Assessment (ASEBA) and the World Health Organization Quality of Life Questionnaire (WHOQOL-BREF). Results showed no significant differences between the group of orphanage graduates and the comparison group. However, using classification procedures we established that living conditions (separate apartment vs. a "public" space - a communal apartment or a dormitory) is an important variable predicting group belonging based on well-being indices. Thus, it appears that in adulthood, it is not the history of institutionalization but the actual living environment that is associated with indicators of the psychological, social and emotional well-being of orphanage graduates.