Unravelling the contributions of motor experience and conceptual knowledge in action perception: A training study

Prior knowledge affects how we perceive the world and the sensorimotor system actively guides our perception. An ongoing dispute regards the extent to which prior motor knowledge versus conceptual knowledge modulates the observation of others’ actions. Research indicates that motor experience increases motor activation during action perception. Other research, however, has shown that conceptual familiarity with actions also modulates motor activation, i.e., increased motor activation during observation of unfamiliar, compared to conceptually familiar, actions. To begin to disentangle motor from conceptual contributions to action perception, we uniquely combined motoric and conceptual interventions into one design. We experimentally manipulated participants’ experience with both motoric skills and conceptual knowledge, via motor training of kinematically challenging actions and contextual information about the action, respectively, in a week-long training session. Measurements of the effects on motor activity measured via electroencephalography (EEG) during pre- and post-training action observation were compared. We found distinct, non-interacting effects of both manipulations: Motor training increased motor activation, whereas additional conceptual knowledge decreased motor activation. The findings indicate that both factors influence action perception in a distinct and parallel manner. This research speaks to previously irreconcilable findings and provides novel insights about the distinct roles of motor and conceptual contributions to action perception

Why do infants imitate selectively? Neural correlates of infants’ action understanding in the head-touch paradigm

Imitation is an important social learning mechanism for young infants exploring the world. Interestingly, infants do not imitate every action they observe – they rather do so selectively. Fourteen-month-olds predominantly imitated an unusual and inefficient action (turning on a lamp with one’s forehead) when the model’s hands were free compared to when the model’s hands were occupied (Gergely et al., 2002). Behavioral scientists have proposed contrasting explanatory accounts, differing with regard to the assumed level of infants’ cognitive abilities. Rational-imitation accounts suggest that infants selectively imitate unusual actions because they are surprised by the inefficiency of the action (Gergely & Csibra, 2003). In contrast, non-rational imitation accounts propose that selective imitation depends on more basic factors such as motor abilities (Paulus et al., 2011a,b). The integrative model by Zmyj and Buttelmann (2014) represents the first attempt to put together these opposing theories. Both accounts may operate on different processing levels. Bottom-up processes are related to non-rational imitation accounts, whereas top-down processing is based on the assumptions of the rational-imitation accounts. Despite the large body of behavioral research on selective imitation, the question of what are the neural mechanisms underlying these processes remains unanswered. In my dissertation, I aimed to uncover the underlying cognitive processes during the observation of head-touch actions by recording infants’ neurophysiological responses in three empirical studies. To test the assumptions of the top-down processes linked to the rational-imitation accounts, I examined neural markers associated with violation of expectation (VOE) in an adaptation of the head-touch paradigm. Overall, results suggest that 12- to 14-month-old infants, but not 9-month-old infants, display VOE when observing a person performing an inefficient head touch. This VOE response is context-dependent and is elicited when the model’s hands are free but not when the hands are restrained. In Study 1, VOE has been linked to a reduction in mu power in response to the unexpected head touch. In Study 2, this finding was extended such that when 12- to 14-month-old infants observed an unexpected head touch, their brains responded with increased attentional engagement (enhanced Nc amplitude) and a detection of a semantic violation (N400 component). Finally, in Study 3, in the absence of contextual information, 1-year-olds discriminated between hand- and head-touch outcomes on the Nc component only. Thus, infants require information of the action context to detect semantic violations within the head-touch paradigm. To conclude, the studies presented in my dissertation have paved the way to further our understanding of infants’ action perception and observational learning. Understanding the neural mechanisms of infants’ action perception in more depth, will help us to adequately foster the ideal observational learning conditions of novel actions. The results of this dissertation suggest that presenting infants with surprising action means puts them in an optimal receptive state for knowledge acquisition

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

Links between action perception and action production in 10-week-old infants

Abstract In order to understand how experience of an action alters functional brain responses to visual information, we examined the effects of reflex walking on how 10-week-old infants processed biological motion. We gave experience of the reflex walk to half the participants, and did not give this experience to the other half of the sample. The participant's electrical brain activity in response to viewing upright and inverted walking and crawling movements indicated the detection of biological motion only for that group which experience the reflex walk, as evidenced by parietal electrode greater positivity for the upright than the inverted condition. This effect was observed only for the walking stimuli. This study suggests that parietal regions are associated with the perception of biological motion even at 9–11 weeks. Further, this result strongly suggests that experience refines the perception of biological motion and that at 10 weeks of age, the link between action perception and action production is tightly woven

Drivers of social cognitive development in human and non-human primate infants

From prosocial behavior to cultural learning and belief understanding, social cognitive skills are important for engagement in social interactions and learning from others. In this chapter, we review some probable foundational skills of social cognitive development in human and non-human primate (NHP) infants. We selectively discuss capacities that are early-emerging and shared across species, with the goal of illustrating the value of a comparative developmental approach in advancing our understanding of early social cognitive development. In particular, this chapter focuses on exploring the role that a comparative developmental approach may play in identifying foundational social cognitive abilities and the drivers of these early-emerging skills in human infants

Our own action kinematics predict the perceived affective states of others.

Our movement kinematics provideuseful cues aboutour affective states. Given that our experiences furnish models that help us to interpret our environment, and that a rich source of action experience comes from our own movements,the present study examined whetherwe use models of our own action kinematics to make judgments about the affective states of others. For example,relative to one’s typical kinematics, anger isassociated with fast movements. Therefore, the extent to which we perceive angerin others maybe determined by the degreeto which their movementsare faster than our own typicalmovements. We related participants’walking kinematicsin a neutral contextto their judgments of the affective statesconveyed byobserved point-light walkers(PLWs). Aspredicted,we found a linear relationship between one’s own walking kinematics and affective state judgments, such that faster participants rated sloweremotionsmore intensely relative to their ratings for faster emotions. This relationship was absent when observing PLWs where differences in velocity between affective states were removed. These findings suggest that perception of affective states in others is predicted by one’s own movement kinematics, withimportant implications for perception of, and interaction with,those who move differentl

Effects of docosahexaenoic acid intake during pregnancy and lactation on infant growth and neurocognitive development and the associated effects of genetic variants of the FADS1 FADS2 gene cluster, The

2014 Summer.Maternal docosahexaenoic acid (DHA) intake during pregnancy and/or lactation has been positively associated with infant growth and neurocognitive development. However, randomized controlled clinical trials (RCT) report mixed results. Several RCT that failed to demonstrate an effect of DHA supplementation have found correlations between DHA status and cognitive benefits, possibly due to a failure to account for total maternal DHA intake. The majority of studies to date investigating neurocognitive development have not examined the effect of supplementing women with DHA during both pregnancy and lactation and fail to determine the effects of maternal genetic variation on infant neurocognitive development. Single nucleotide polymorphisms (SNPs) within the fatty acid desaturase (FADS)1 FADS2 gene cluster encoding for Δ5- and Δ6-desaturase enzymes were previously reported to be associated with altered omega-3 (n-3) and omega-6 (n-6) fatty acid proportions of erythrocyte, plasma phospholipids and breastmilk, possibly effecting DHA transfer to the infant. This study was conducted to determine the relationship between DHA intake in women obtaining varying amounts of DHA daily during pregnancy and lactation and infant neurocognitive development in the first year of life and the association of maternal SNPs in the FADS1 FADS2 gene cluster. One hundred and fifteen pregnant women were randomized to receive purified tuna oil supplement containing 300 mg of DHA and 67 mg EPA per day or an identical placebo (Sunola oil) for the last trimester of pregnancy through the first 3 months of lactation in a double-blinded placebo controlled clinical trial. Two SNPs in the FADS1 FADS2 gene cluster, rs174575 and rs174561, were genotyped from maternal DNA and erythrocyte, plasma phospholipid and breastmilk fatty acids and daily DHA intake from food frequency questionnaires (FFQ) were analyzed. Neurocognitive development of the infants was measured using the Mental Development Index (MDI) of the Bayley Scales of Infant Development III (BSID-III) at 4 and 12 months of age. Gestational length in days was calculated based upon last menstrual period and birth date. Infant birth weights and lengths were obtained from pediatric medical records at delivery and at 2 months of age. Total daily DHA intake was estimated to range from 18 mg to 1.374 g per day calculated from all sources of DHA, including food and supplementation. Data was analyzed based on treatment group, placebo versus DHA, and by total daily DHA intake broken into three groups: low = 0-299 mg per day DHA, medium = 300-599 mg per day DHA, high = ≥600 mg per day DHA. DHA portion of 2 month breastmilk fatty acids directly correlated with daily DHA intake (r=0.37, p=0.0002). Erythrocyte and breastmilk DHA proportions significantly increased in women homozygous for the major allele (SNP rs174575, p=0.0002 and p=0.030, respectively; SNP rs174561, p=0.003 and p=0.040, respectively) in the high daily DHA intake compared to the low intake group. However, daily DHA intake had no effect significantly increasing DHA proportions in women homozygous for the minor alleles of both SNPs studied. Infants born to mothers in the high DHA intake group showed significantly higher scores on the 12 month cognitive scale of the MDI of the BSID-III (p=0.018), compared to the low intake group. No significant differences were seen between treatment groups or DHA intake groups on any of the 4 month infant cognitive testing. Genotype had no direct effect on BSID-III scores, however, ANCOVA for 12 month cognitive MDI subtest showed a statistically significant interaction between SNP rs174575 genotype and daily DHA intake group (p=0.023). Additionally, infants born to mothers in the DHA treatment group had an increase of 4.5 days in gestational age (p=0.048) and significantly lower incidence of preterm birth (5%; n=3) compared to infants born to mothers in the control group (18%; n=10; χ2=4.97, p=0.026). No significant differences were seen between treatment groups or DHA intake groups in infant growth measurements at birth or at 2 months of age, although 2 month breastmilk DHA proportion of fatty acids was negatively correlated with 2 month weight (r= -0.22, p=0.048). An intake of 600 mg of DHA per day or greater during the third trimester of gestation throughout the first three months of breastfeeding was associated with improved infant neurocognitive development. Genetic variants of the FADS1 FADS2 gene cluster influence erythrocyte and breastmilk fatty acids, and increased DHA intake does not effectively increase DHA proportions in minor allele carriers. Additionally, DHA supplementation increased gestational length and decreased preterm birth risk, however, did not affect infant birth weights. DHA supplementation during pregnancy and lactation could be beneficial for improving the neurocognitive development of infants, however, genetic variation may affect DHA transfer to the infant

Interaction takes two: typical adults exhibit mind-blindness towards those with Autism Spectrum Disorder

Recent work suggests that we are better at interpreting the movements of others who move like us, and that individuals with Autism Spectrum Disorder (ASD) move in a quantifiably different way from typical individuals. Therefore, ‘social impairments’ exhibited by individuals with ASD may, at least in part, represent a failure by typical individuals to infer the correct mental states from the movements of those with ASD. To examine this possibility, individuals with ASD and typical adults manually directed two triangles to generate animations depicting mental state interactions. Kinematic analysis of the generated animations demonstrated that the participants with ASD moved atypically, specifically with increased jerk compared to the typical participants. In confirmation of our primary hypothesis, typical individuals were better able to identify the mental state portrayed in the animations produced by typical, relative to autistic individuals. The participants with ASD did not show this ‘same group’ advantage, demonstrating comparable performance for the two sets of animations. These findings have significant implications for clinical assessment and intervention in ASD, and potentially other populations with atypical movement

Precursors to language development in typically and atypically developing infants and toddlers: the importance of embracing complexity

In order to understand how language abilities emerge in typically and atypically developing infants and toddlers, it is important to embrace complexity in development. In this paper, we describe evidence that early language development is an experience-dependent process, shaped by diverse, interconnected, interdependent developmental mechanisms, processes, and abilities (e.g. statistical learning, sampling, functional specialization, visual attention, social interaction, motor ability). We also present evidence from our studies on neurodevelopmental disorders (e.g. Down syndrome, fragile X syndrome, Williams syndrome) that variations in these factors significantly contribute to language delay. Finally, we discuss how embracing complexity, which involves integrating data from different domains and levels of description across developmental time, may lead to a better understanding of language development and, critically, lead to more effective interventions for cases when language develops atypically