Toddlers' action prediction: statistical learning of continuous action sequences

The current eye-tracking study investigated whether toddlers use statistical information to make anticipatory eye movements while observing continuous action sequences. In two conditions, 19-month-old participants watched either a person performing an action sequence (Agent condition) or a self-propelled visual event sequence (Ghost condition). Both sequences featured a statistical structure in which certain action pairs occurred with deterministic transitional probabilities. Toddlers learned the transitional probabilities between the action steps of the deterministic action pairs and made predictive fixations to the location of the next action in the Agent condition but not in the Ghost condition. These findings suggest that young toddlers gain unique information from the statistical structure contained within action sequences and are able to successfully predict upcoming action steps based on this acquired knowledge. Furthermore, predictive gaze behavior was correlated with reproduction of sequential actions following exposure to statistical regularities. This study extends previous developmental work by showing that statistical learning can guide the emergence of anticipatory eye movements during observation of continuous action sequences

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

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

Translating visual information into action predictions: Statistical learning in action and non-action contexts

Humans are sensitive to the statistical regularities in action sequences carried out by others. In the present eyetracking study, we investigated whether this sensitivity can support the prediction of upcoming actions when observing unfamiliar action sequences. In two between-subjects conditions, we examined whether observers would be more sensitive to statistical regularities in sequences performed by a human agent versus self-propelled ‘ghost’ events. Secondly, we investigated whether regularities are learned better when they are associated with contingent effects. Both implicit and explicit measures of learning were compared between agent and ghost conditions. Implicit learning was measured via predictive eye movements to upcoming actions or events, and explicit learning was measured via both uninstructed reproduction of the action sequences and verbal reports of the regularities. The findings revealed that participants, regardless of condition, readily learned the regularities and made correct predictive eye movements to upcoming events during online observation. However, different patterns of explicit-learning outcomes emerged following observation: Participants were most likely to re-create the sequence regularities and to verbally report them when they had observed an actor create a contingent effect. These results suggest that the shift from implicit predictions to explicit knowledge of what has been learned is facilitated when observers perceive another agent’s actions and when these actions cause effects. These findings are discussed with respect to the potential role of the motor system in modulating how statistical regularities are learned and used to modify behavior

What’s going on in babies’ brains when they learn to do something?

Actions are important. We need to know how to do all sorts of actions in our everyday life, like using a fork to eat and using a pen to write. We understand actions we see other people do better if we’ve done the same action before ourselves. It helps us understand why other people choose to use the same action. Adults know lots of different actions, but babies are still learning how to do many things. They are just learning how to move around and how to play with new toys. Babies also understand more about actions they have done before than actions they haven’t done. Is there something happening in their brains that might help them understand the actions they have done? Do babies’ brains respond differently when they perceive an action they know how to do compared to one they have never done? Let’s find out

The infant motor system predicts actions based on visual statistical learning

Motor theories of action prediction propose that our motor system combines prior knowledge with incoming sensory input to predict other people's actions. This prior knowledge can be acquired through observational experience, with statistical learning being one candidate mechanism. But can knowledge learned through observation alone transfer into predictions generated in the motor system? To examine this question, we first trained infants at home with videos of an unfamiliar action sequence featuring statistical regularities. At test, motor activity was measured using EEG and compared during perceptually identical time windows within the sequence that preceded actions which were either predictable (deterministic) or not predictable (random). Findings revealed increased motor activity preceding the deterministic but not the random actions, providing the first evidence that the infant motor system can use knowledge from statistical learning to predict upcoming actions. As such, these results support theories in which the motor system underlies action predictio

Neural tracking in infancy predicts language development in children with and without family history of autism

During speech processing, neural activity in non-autistic adults and infants tracks the speech envelope. Recent research in adults indicates that this neural tracking relates to linguistic knowledge and may be reduced in autism. Such reduced tracking, if present already in infancy, could impede language development. In the current study, we focused on children with a family history of autism, who often show a delay in first language acquisition. We investigated whether differences in tracking of sung nursery rhymes during infancy relate to language development and autism symptoms in childhood. We assessed speech-brain coherence at either 10 or 14 months of age in a total of 22 infants with high likelihood of autism due to family history and 19 infants without family history of autism. We analyzed the relationship between speech-brain coherence in these infants and their vocabulary at 24 months as well as autism symptoms at 36 months. Our results showed significant speech-brain coherence in the 10- and 14-month-old infants. We found no evidence for a relationship between speech-brain coherence and later autism symptoms. Importantly, speech-brain coherence in the stressed syllable rate (1–3 Hz) predicted later vocabulary. Follow-up analyses showed evidence for a relationship between tracking and vocabulary only in 10-month-olds but not 14-month-olds and indicated possible differences between the likelihood groups. Thus, early tracking of sung nursery rhymes is related to language development in childhood

Sensitivity to structure in action sequences:an infant event-related potential study

Infants are sensitive to structure and patterns within continuous streams of sensory input. This sensitivity relies on statistical learning, the ability to detect predictable regularities in spatial and temporal sequences. Recent evidence has shown that infants can detect statistical regularities in action sequences they observe, but little is known about the neural process that give rise to this ability. In the current experiment, we combined electroencephalography (EEG) with eye-tracking to identify electrophysiological markers that indicate whether 8–11-month-old infants detect violations to learned regularities in action sequences, and to relate these markers to behavioral measures of anticipation during learning. In a learning phase, infants observed an actor performing a sequence featuring two deterministic pairs embedded within an otherwise random sequence. Thus, the first action of each pair was predictive of what would occur next. One of the pairs caused an action-effect, whereas the second did not. In a subsequent test phase, infants observed another sequence that included deviant pairs, violating the previously observed action pairs. Event-related potential (ERP) responses were analyzed and compared between the deviant and the original action pairs. Findings reveal that infants demonstrated a greater Negative central (Nc) ERP response to the deviant actions for the pair that caused the action-effect, which was consistent with their visual anticipations during the learning phase. Findings are discussed in terms of the neural and behavioral processes underlying perception and learning of structured action sequences

Robustness of the rule-learning effect in 7-month-old infants: A close, multicenter replication of Marcus et al. (1999)

We conducted a close replication of the seminal work by Marcus and colleagues from 1999, which showed that after a brief auditory exposure phase, 7-month-old infants were able to learn and generalize a rule to novel syllables not previously present in the exposure phase. This work became the foundation for the theoretical framework by which we assume that infants are able to learn abstract representations and generalize linguistic rules. While some extensions on the original work have shown evidence of rule learning, the outcomes are mixed, and an exact replication of Marcus et al.'s study has thus far not been reported. A recent meta-analysis by Rabagliati and colleagues brings to light that the rule-learning effect depends on stimulus type (e.g., meaningfulness, speech vs. nonspeech) and is not as robust as often assumed. In light of the theoretical importance of the issue at stake, it is appropriate and necessary to assess the replicability and robustness of Marcus et al.'s findings. Here we have undertaken a replication across four labs with a large sample of 7-month-old infants (N = 96), using the same exposure patterns (ABA and ABB), methodology (Headturn Preference Paradigm), and original stimuli. As in the original study, we tested the hypothesis that infants are able to learn abstract “algebraic” rules and apply them to novel input. Our results did not replicate the original findings: infants showed no difference in looking time between test patterns consistent or inconsistent with the familiarization pattern they were exposed to