Social context influences planning ahead in three-year-olds

Children’s joint action and advance planning skills are both undergoing development during the preschool years, but little is known about how joint action contexts influence children’s advance planning. In the first experiment, three-year-olds (N = 32) were better at planning ahead for a task in an individual compared to a joint condition when playing with a social partner. A second experiment indicated that three-year-olds (N = 32) were as able to plan in advance with a non-social machine as when playing alone, suggesting that the effects found in the first experiment were not a function of different timing or cognitive demands between individual and joint conditions, but were unique to the social context

Dynamic Modeling of the Geological CO2 Storage in Fractured Aquifers – Application to the Ordos Basin CCS Project

Unique reservoir performance was observed in the Shenhua (100,000 metric tons/year) Carbon Capture and Storage (SHCCS) Demonstration Project. Hydraulic fracturing and a multi-layer injection procedure were employed to improve the reservoir injectivity and to reduce the overpressure risk. However, in-situ data showed that the total injection rate increased over the years, while the corresponding injection pressure decreased. Only four of the 21 injection aquifers did absorb CO2 during all of the injection tests from 2011 to 2014, while others stopped absorbing CO2 in the injection tests after 2011. Additionally, the uppermost injection layer, which was unfractured, had a considerable increase in injectivity over the years and absorbed the majority of the injected CO2 from 2012. Investigation into reservoir performance dynamics for this project was conducted through numerical simulations using TOUGH2-MP-ECO2N. The main features of the reservoir performance were reproduced through a heterogeneous model by using a time-dependent pressure boundary condition at the injection well. The results indicated that the heterogeneous distributions of permeability in the injection layers could be the cause for the observed dynamic reservoir performance. CO2-absorbing predominance of the uppermost injection layer could be attributed to its much higher overall permeability than that of other injection layers. A substantial increase in injectivity of this layer over the years could be explained by the permeability becoming considerably higher away from the injection well in a north-westerly direction. The induced fractures in the reservoir can greatly improve the injectivity at early injection, but this improvement dramatically declined afterwards. The intermittent injection procedure was helpful in keeping the pressure build-up low in the reservoir and the injection rate at the target level, and the accompanying hysteresis effects could improve the injectivity and storage safety

Preview of partial stimulus information in search prioritizes features and conjunctions, not locations

Contains fulltext : 216040.pdf (publisher's version ) (Open Access)Visual search often requires combining information on distinct visual features such as color and orientation, but how the visual system does this is not fully understood. To better understand this, we showed observers a brief preview of part of a search stimulus - either its color or orientation - before they performed a conjunction search task. Our experimental questions were (1) whether observers would use such previews to prioritize either potential target locations or features, and (2) which neural mechanisms might underlie the observed effects. In two experiments, participants searched for a prespecified target in a display consisting of bar elements, each combining one of two possible colors and one of two possible orientations. Participants responded by making an eye movement to the selected bar. In our first experiment, we found that a preview consisting of colored bars with identical orientation improved saccadic target selection performance, while a preview of oriented gray bars substantially decreased performance. In a follow-up experiment, we found that previews consisting of discs of the same color as the bars (and thus without orientation information) hardly affected performance. Thus, performance improved only when the preview combined color and (noninformative) orientation information. Previews apparently result in a prioritization of features and conjunctions rather than of spatial locations (in the latter case, all previews should have had similar effects). Our results thus also indicate that search for, and prioritization of, combinations involve conjunctively tuned neural mechanisms. These probably reside at the level of the primary visual cortex.13 p

Joint Action Coordination in 2½- and 3-Year-Old Children

When acting jointly with others, adults can be as proficient as when acting individually. However, how young children coordinate their actions with another person and how their action coordination develops during early childhood is not well understood. By means of a sequential button-pressing game, which could be played jointly or individually, the action coordination of 2½- and 3-year-old children was examined. Performance accuracy and variability of response timing were taken as indicators of coordination ability. Results showed substantial improvement in joint action coordination between the age of 2½ and 3, but both age groups performed equally well when acting individually. Interestingly, 3-year-olds performed equally well in the joint and the individual condition, whereas 2½-year-olds did not yet show this adult-like pattern as indicated by less accurate performance in the joint action. The findings suggest that in contrast to 3-year-olds, 2½-year-olds still have difficulties in establishing well-coordinated joint action with an adult partner. Possible underlying cognitive abilities such as action planning and action control are discussed

The Role of Conflicting Representations and Uncertainty in Internal Error Detection During L2 Learning

Internal error monitoring as reflected by the error-related negativity (ERN) component can give insight in the L2 learning process. Yet, beginning stages of learning are characterized by high levels of uncertainty, which obscures the process of error detection. We examine how uncertainty about L2 syntactic representations, induced by different levels of language conflict, is reflected in the ERN effect during learning. German learners of Dutch performed a feedback-guided gender decision task in their L2 and were asked to give subjective certainty ratings for their responses. Results indicate that initially, high conflict items yielded more uncertainty and showed an inverse ERN effect, i.e., larger negativities for correct compared to erroneous responses. Two rounds of feedback resulted in an increase of behavioural accuracy, lower levels of uncertainty, and an expected ERN effect, signalling effective error monitoring. These outcomes demonstrate how subjective intuitions about response accuracy affect performance monitoring during L2 learning

Virtual Lesions of the IFG Abolish Response Facilitation for Biological and Non-Biological Cues

Humans are faster to perform a given action following observation of that same action. Converging evidence suggests that the human mirror neuron system (MNS) plays an important role in this phenomenon. However, the specificity of the neural mechanisms governing this effect remain controversial. Specialist theories of imitation suggest that biological cues are maximally capable of eliciting imitative facilitation. Generalist models, on the other hand, posit a broader role for the MNS in linking visual stimuli with appropriate responses. In the present study, we investigated the validity of these two theoretical approaches by disrupting the left and right inferior frontal gyrus (IFG) during the preparation of congruent (imitative) and incongruent (complementary) actions cued by either biological (hand) or non-biological (static dot) stimuli. Delivery of TMS over IFG abolished imitative response facilitation. Critically, this effect was identical whether actions were cued by biological or non-biological stimuli. This finding argues against theories of imitation in which biological stimuli are treated preferentially and stresses the notion of the IFG as a vital center of general perception–action coupling in the human brain

Embodied Language Comprehension Requires an Enactivist Paradigm of Cognition

Two recurrent concerns in discussions on an embodied view of cognition are the “necessity question” (i.e., is activation in modality-specific brain areas necessary for language comprehension?) and the “simulation constraint” (i.e., how do we understand language for which we lack the relevant experiences?). In the present paper we argue that the criticisms encountered by the embodied approach hinge on a cognitivist interpretation of embodiment. We argue that the data relating sensorimotor activation to language comprehension can best be interpreted as supporting a non-representationalist, enactivist model of language comprehension, according to which language comprehension can be described as procedural knowledge – knowledge how, not knowledge that – that enables us to interact with others in a shared physical world. The enactivist view implies that the activation of modality-specific brain areas during language processing reflects the employment of sensorimotor skills and that language comprehension is a context-bound phenomenon. Importantly, an enactivist view provides an embodied approach of language, while avoiding the problems encountered by a cognitivist interpretation of embodiment

Movement-Specific Repetition Suppression in Ventral and Dorsal Premotor Cortex during Action Observation

There are several models of premotor cortex contributions to sensorimotor behavior. For instance, the ventral premotor cortex (PMv) appears to be involved in processing visuospatial object properties for grasping, whereas the dorsal premotor cortex (PMd) is involved in using arbitrary rules to guide advance motor planning. These models have focused on individual movements. Here, we examine the premotor responses evoked during the processing of individual movements functionally embedded in an action. We tested whether processing hand–object interactions and action end states would differentially engage PMv and PMd. We used a repetition suppression (RS)–functional magnetic resonance imaging paradigm in which we independently manipulated the observed grip, the end position of the object (independent of its spatial location), and the hand trajectory. By comparing novel and repeated trials for each of these action components, we could isolate RS effects specific to each of them. Repeating the grasp component attenuated activity in right PMv, whereas repeating the end state of the action reduced blood oxygen level–dependent activity in the left PMd. These results suggest that PMv is involved in controlling the kinematic means of an appropriate hand–object interaction, whereas PMd is focused on specifying the desired end state of an action

Context Effects in Embodied Lexical-Semantic Processing

The embodied view of language comprehension proposes that the meaning of words is grounded in perception and action rather than represented in abstract amodal symbols. Support for embodied theories of language processing comes from behavioral studies showing that understanding a sentence about an action can modulate congruent and incongruent physical responses, suggesting motor involvement during comprehension of sentences referring to bodily movement. Additionally, several neuroimaging studies have provided evidence that comprehending single words denoting manipulable objects elicits specific responses in the neural motor system. An interesting question that remains is whether action semantic knowledge is directly activated as motor simulations in the brain, or rather modulated by the semantic context in which action words are encountered. In the current paper we investigated the nature of conceptual representations using a go/no-go lexical decision task. Specifically, target words were either presented in a semantic context that emphasized dominant action features (features related to the functional use of an object) or non-dominant action features. The response latencies in a lexical decision task reveal that participants were faster to respond to words denoting objects for which the functional use was congruent with the prepared movement. This facilitation effect, however, was only apparent when the semantic context emphasized corresponding motor properties. These findings suggest that conceptual processing is a context-dependent process that incorporates motor-related knowledge in a flexible manner

Semantics in the Motor System: Motor-Cortical Beta Oscillations Reflect Semantic Knowledge of End-Postures for Object Use

In the present EEG study we investigated whether semantic knowledge for object use is represented in motor-related brain areas. Subjects were required to perform actions with everyday objects and to maintain either a meaningful or a meaningless end posture with the object. Analysis of the EEG data focused on the beta-frequency band, as previous studies have indicated that the maintenance of a posture is reflected in stronger beta-oscillations. Time frequency analysis indicated that the execution of actions resulting in a meaningless compared to a meaningful end posture was accompanied by a stronger beta-desynchronization towards the end of the movement and a stronger subsequent beta-rebound after posture-onset. The effect in the beta-frequency band was localized to premotor, parietal and medial frontal areas and could not be attributed to differences in timing or movement complexity between meaningful and meaningless actions. Together these findings directly show that the motor system is differentially activated during the execution and maintenance of semantically correct or incorrect end postures. This suggests that semantic object knowledge is indeed represented in motor-related brain areas, organized around specific end postures associated with the use of objects