Showing papers in "Developmental Science in 2011"
TL;DR: For instance, the authors found that the presence of peers may promote adolescent risk taking by sensitizing brain regions associated with the anticipation of potential rewards, including the ventral striatum and orbitofrontal cortex.
Abstract: The presence of peers increases risk taking among adolescents but not adults. We posited that the presence of peers may promote adolescent risk taking by sensitizing brain regions associated with the anticipation of potential rewards. Using fMRI, we measured brain activity in adolescents, young adults, and adults as they made decisions in a simulated driving task. Participants completed one task block while alone, and one block while their performance was observed by peers in an adjacent room. During peer observation blocks, adolescents selectively demonstrated greater activation in reward-related brain regions, including the ventral striatum and orbitofrontal cortex, and activity in these regions predicted subsequent risk taking. Brain areas associated with cognitive control were less strongly recruited by adolescents than adults, but activity in the cognitive control system did not vary with social context. Results suggest that the presence of peers increases adolescent risk taking by heightening sensitivity to the potential reward value of risky decisions.
937 citations
TL;DR: It is found that children's ANS acuity correlated with their math ability, even when age and verbal skills were controlled for, providing evidence for a relationship between the primitive sense of number and math ability starting early in life.
Abstract: Previous research shows a correlation between individual differences in people’s school math abilities and the accuracy with which they rapidly and nonverbally approximate how many items are in a scene. This finding is surprising because the Approximate Number System (ANS) underlying numerical estimation is shared with infants and with non-human animals who never acquire formal mathematics. However, it remains unclear whether the link between individual differences in math ability and the ANS depends on formal mathematics instruction. Earlier studies demonstrating this link tested participants only after they had received many years of mathematics education, or assessed participants’ ANS acuity using tasks that required additional symbolic or arithmetic processing similar to that required in standardized math tests. To ask whether the ANS and math ability are linked early in life, we measured the ANS acuity of 200 3- to 5-year-old children using a task that did not also require symbol use or arithmetic calculation. We also measured children’s math ability and vocabulary size prior to the onset of formal math instruction. We found that children’s ANS acuity correlated with their math ability, even when age and verbal skills were controlled for. These findings provide evidence for a relationship between the primitive sense of number and math ability starting early in life.
441 citations
TL;DR: Results indicated that OT in plasma (pOT) and saliva (sOT) were inter-related and were unrelated to OT in urine (uOT), whereas uOT correlated with relationship anxiety and parenting stress among mothers only.
Abstract: Studies in mammals have implicated the neuropeptide oxytocin (OT) in processes of bond formation and stress modulation, yet the involvement of OT in human bonding throughout life remains poorly understood. We assessed OT in the plasma, saliva, and urine of 112 mothers and fathers interacting with their 4-6-month-old infants. Parent-infant interactions were micro-coded for parent and child's social behaviors and for the temporal coordination of their socio-affective cues. Parents were interviewed regarding their attachment to the infant and reported on bonding to own parents, romantic attachment, and parenting stress. Results indicated that OT in plasma (pOT) and saliva (sOT) were inter-related and were unrelated to OT in urine (uOT). pOT and sOT in mothers and fathers were associated with parent and child's social engagement, affect synchrony, and positive communicative sequences between parent and child. uOT was related to moments of interactive stress among mothers only, indexed by the co-occurrence of infant negative engagement and mother re-engagement attempts. pOT and sOT were associated with mothers' and fathers' attachment relationships throughout life: to own parents, partner, and infant, whereas uOT correlated with relationship anxiety and parenting stress among mothers only. Similar to other mammals, OT is involved in human attachment and contingent parenting. The dual role of OT in stress and affiliation underscores its complex involvement in processes of social bonding throughout life.
420 citations
TL;DR: Data support the hypothesis that early adversity alters human brain development in a way that can persist into childhood, and they offer insight into the socio-emotional disturbances in human behavior following early adversity.
Abstract: A functional neuroimaging study examined the long-term neural correlates of early adverse rearing conditions in humans as they relate to socio-emotional development. Previously institutionalized (PI) children and a same-aged comparison group were scanned using functional magnetic resonance imaging (fMRI) while performing an Emotional Face Go/Nogo task. PI children showed heightened activity of the amygdala, a region that supports emotional learning and reactivity to emotional stimuli, and corresponding decreases in cortical regions that support perceptual and cognitive functions. Amygdala activity was associated with decreased eye-contact as measured by eye-tracking methods and during a live dyadic interaction. The association between early rearing environment and subsequent eye-contact was mediated by amygdala activity. These data support the hypothesis that early adversity alters human brain development in a way that can persist into childhood, and they offer insight into the socio-emotional disturbances in human behavior following early adversity.
420 citations
TL;DR: In two experiments, infants' looking times and manual choices provide converging evidence suggesting that infants aged 12 to 18 months (mean age 16 months) attend to the outcomes of distributive actions to evaluate agents' actions and to reason about agents' dispositions.
Abstract: The problem of how to distribute available resources among members of a group is a central aspect of social life. Adults react negatively to inequitable distributions and several studies have reported negative reactions to inequity also in non-human primates and dogs. We report two experiments on infants' reactions to equal and unequal distributions. In two experiments, infants' looking times and manual choices provide, for the first time, converging evidence suggesting that infants aged 12 to 18 months (mean age 16 months) attend to the outcomes of distributive actions to evaluate agents' actions and to reason about agents' dispositions. The results provide support for recent theoretical proposals on the developmental roots of social evaluation skills and a sense of fairness.
369 citations
TL;DR: This work demonstrates that proportion-judgment models provide a unified account of estimation patterns that have previously been explained in terms of a developmental shift from logarithmic to linear representations of number.
Abstract: How do our mental representations of number change over development? The dominant view holds that children (and adults) possess multiple representations of number, and that age and experience lead to a shift from greater reliance upon logarithmically organized number representations to greater reliance upon more accurate, linear representations. Here we present a new theoretically motivated and empirically supported account of the development of numerical estimation, based on the idea that number-line estimation tasks entail judgments of proportion. We extend existing models of perceptual proportion judgment to the case of abstract numerical magnitude. Two experiments provide support for these models; three likely sources of developmental change in children’s estimation performance are identified and discussed. This work demonstrates that proportion-judgment models provide a unified account of estimation patterns that have previously been explained in terms of a developmental shift from logarithmic to linear representations of number.
343 citations
TL;DR: It is proposed that children orient towards members of their native community to guide their early cultural learning and demonstrate selective trust in native-accented speakers even when neither informant's speech relays meaningful semantic content, and the information that both informants provide is non-linguistic.
Abstract: Across two experiments, preschool-aged children demonstrated selective learning of non-linguistic information from native-accented rather than foreign-accented speakers. In Experiment 1, children saw videos of a native- and a foreign-accented speaker of English who each spoke for 10 seconds, and then silently demonstrated different functions with novel objects. Children selectively endorsed the silent object function provided by the native-accented speaker. In Experiment 2, children again endorsed the native-accented over the foreign-accented speaker, even though both informants previously spoke only in nonsense speech. Thus, young children demonstrate selective trust in native-accented speakers even when neither informant’s speech relays meaningful semantic content, and the information that both informants provide is non-linguistic. We propose that children orient towards members of their native community to guide their early cultural learning.
337 citations
TL;DR: Results indicate that increases in cardiorespiratory fitness are associated with improvements in the cognitive control of working memory in preadolescent children.
Abstract: The present study examined the effects of a 9-month randomized control physical activity intervention aimed at improving cardiorespiratory fitness on changes in working memory performance in preadolescent children relative to a waitlist control group. Participants performed a modified Sternberg task, which manipulated working memory demands based on encoding set sizes, while task performance and the contingent negative variation (CNV) event-related brain potential were measured. Analyses revealed that the physical activity intervention led to increases in cardiorespiratory fitness and improved Sternberg task performance. Further, the beneficial effects of the physical activity intervention were greater for a task condition requiring greater working memory demands. In addition, the intervention group exhibited larger initial CNV at the frontal electrode site, relative to the waitlist group at post-test; an effect not observed during the pre-test. These results indicate that increases in cardiorespiratory fitness are associated with improvements in the cognitive control of working memory in preadolescent children.
324 citations
TL;DR: It is found that parents vary widely in the amount of spatial language they use with their children during everyday interactions, and that children who produce more spatial language are more likely to perform better on spatial problem solving tasks at a later age.
Abstract: In this paper we examine the relations between parent spatial language input, children’s own production of spatial language, and children’s later spatial abilities. Using a longitudinal study design, we coded the use of spatial language (i.e. words describing the spatial features and properties of objects; e.g. big, tall, circle, curvy, edge) from child age 14 to 46 months in a diverse sample of 52 parent–child dyads interacting in their home settings. These same children were given three non-verbal spatial tasks, items from a Spatial Transformation task (Levine et al., 1999), the Block Design subtest from the WPPSI-III (Wechsler, 2002), and items on the Spatial Analogies subtest from Primary Test of Cognitive Skills (Huttenlocher & Levine, 1990) at 54 months of age. We find that parents vary widely in the amount of spatial language they use with their children during everyday interactions. This variability in spatial language input, in turn, predicts the amount of spatial language children produce, controlling for overall parent language input. Furthermore, children who produce more spatial language are more likely to perform better on spatial problem solving tasks at a later age.
319 citations
TL;DR: It is found that parents' number talk involving counting or labeling sets of present, visible objects is related to children's later cardinal-number knowledge, whereas other types of parent number talk are not.
Abstract: Before they enter preschool, children vary greatly in their numerical and mathematical knowledge, and this knowledge predicts their achievement throughout elementary school (e.g. Duncan et al., 2007; Ginsburg & Russell, 1981). Therefore, it is critical that we look to the home environment for parental inputs that may lead to these early variations. Recent work has shown that the amount of number talk that parents engage in with their children is robustly related to a critical aspect of mathematical development – cardinal-number knowledge (e.g. knowing that the word ‘three’ refers to sets of three entities; Levine, Suriyakham, Rowe, Huttenlocher & Gunderson, 2010). The present study characterizes the different types of number talk that parents produce and investigates which types are most predictive of children’s later cardinal-number knowledge. We find that parents’ number talk involving counting or labeling sets of present, visible objects is related to children’s later cardinal-number knowledge, whereas other types of parent number talk are not. In addition, number talk that refers to large sets of present objects (i.e. sets of size 4 to 10 that fall outside children’s ability to track individual objects) is more robustly predictive of children’s later cardinal-number knowledge than talk about smaller sets. The relation between parents’ number talk about large sets of present objects and children’s cardinal-number knowledge remains significant even when controlling for factors such as parents’ socioeconomic status and other measures of parents’ number and non-number talk.
272 citations
TL;DR: This paper showed that it is possible to improve fluid intelligence (Gf) with training, which could have implications for early interventions in children, and showed that the non-verbal reasoning training group improved significantly on Gf when analysed as a latent variable of several reasoning tasks.
Abstract: Fluid intelligence (Gf) predicts performance on a wide range of cognitive activities, and children with impaired Gf often experience academic difficulties. Previous attempts to improve Gf have been hampered by poor control conditions and single outcome measures. It is thus still an open question whether Gf can be improved by training. This study included 4-year-old children (N = 101) who performed computerized training (15 min/day for 25 days) of either non-verbal reasoning, working memory, a combination of both, or a placebo version of the combined training. Compared to the placebo group, the non-verbal reasoning training group improved significantly on Gf when analysed as a latent variable of several reasoning tasks. Smaller gains on problem solving tests were seen in the combination training group. The group training working memory improved on measures of working memory, but not on problem solving tests. This study shows that it is possible to improve Gf with training, which could have implications for early interventions in children.
TL;DR: In a detailed and wide-ranging review of research on imitation and imitation-relevant behaviour in infancy and beyond, there is substantially more evidence in favour of the wealth argument than of the poverty argument.
Abstract: Imitation requires the imitator to solve the correspondence problem--to translate visual information from modelled action into matching motor output. It has been widely accepted for some 30 years that the correspondence problem is solved by a specialized, innate cognitive mechanism. This is the conclusion of a poverty of the stimulus argument, realized in the active intermodal matching model of imitation, which assumes that human neonates can imitate a range of body movements. An alternative, wealth of the stimulus argument, embodied in the associative sequence learning model of imitation, proposes that the correspondence problem is solved by sensorimotor learning, and that the experience necessary for this kind of learning is provided by the sociocultural environment during human development. In a detailed and wide-ranging review of research on imitation and imitation-relevant behaviour in infancy and beyond, we find substantially more evidence in favour of the wealth argument than of the poverty argument.
TL;DR: This study identified deficits in executive functioning in pre-adolescent preterms and modeled their role, along with processing speed, in explaining preterm/full-term differences in reading and mathematics, and identified the best-fitting structural equation model.
Abstract: This study identified deficits in executive functioning in pre-adolescent preterms and modeled their role, along with processing speed, in explaining preterm/full-term differences in reading and mathematics. Preterms (< 1750 g) showed deficits at 11 years on a battery of tasks tapping the three basic executive functions identified by Miyake - updating/working memory, inhibition, and shifting. Confirmatory factor analysis showed that these executive functions, though correlated, were distinct from one another and from processing speed, which later proved to account for much of the intercorrelation among executive functions. In the best-fitting structural equation model, the negative effects of prematurity on achievement were completely mediated by the three executive functions and speed in a cascade of effects: prematurity → slower processing speed → poorer executive functioning (working memory) → lower achievement in math and reading.
TL;DR: Findings underscore the need to examine the dimensions, mechanisms, and individual pathways that influence the development of early competence in basic cognitive processes that underpin early academic achievement.
Abstract: Latent variable modeling methods have demonstrated utility for understanding the structure of executive control (EC) across development. These methods are utilized to better characterize the relation between EC and mathematics achievement in the preschool period, and to understand contributing sources of individual variation. Using the sample and battery of laboratory tasks described in Wiebe, Espy and Charak (2008), latent EC was related strongly to emergent mathematics achievement in preschool, and was robust after controlling for crystallized intellectual skills. The relation between crystallized skills and emergent mathematics differed between girls and boys, although the predictive association between EC and mathematics did not. Two dimensions of the child 's social environment contributed to mathematics achievement: social network support through its relation to EC and environmental stressors through its relation with crystallized skills. These findings underscore the need to examine the dimensions, mechanisms, and individual pathways that influence the development of early competence in basic cognitive processes that underpin early academic achievement.
TL;DR: Counter to widespread belief, these results indicate that both fluid reasoning and processing speed are modifiable by training.
Abstract: The goal of this study was to determine whether intensive training can ameliorate cognitive skills in children. Children aged 7 to 9 from low socioeconomic backgrounds participated in one of two cognitive training programs for 60 minutes ⁄ day and 2 days ⁄ week, for a total of 8 weeks. Both training programs consisted of commercially available computerized and noncomputerized games. Reasoning training emphasized planning and relational integration; speed training emphasized rapid visual detection and rapid motor responses. Standard assessments of reasoning ability – the Test of Non-Verbal Intelligence (TONI-3) and cognitive speed (Coding B from WISC IV) – were administered to all children before and after training. Neither group was exposed to these standardized tests during training. Children in the reasoning group improved substantially on TONI (Cohen’s d = 1.51), exhibiting an average increase of 10 points in Performance IQ, but did not improve on Coding. By contrast, children in the speed group improved substantially on Coding (d = 1.15), but did not improve on TONI. Counter to widespread belief, these results indicate that both fluid reasoning and processing speed are modifiable by training.
TL;DR: In an effort to understand how toddlers' bodily actions structure the visual learning environment, mini-video cameras were placed low on the foreheads of toddlers, and for comparison also on theForeheads of their parents, as they jointly played with toys.
Abstract: Human toddlers learn about objects through second-by-second, minute-by-minute sensory-motor interactions. In an effort to understand how toddlers’ bodily actions structure the visual learning environment, mini-video cameras were placed low on the foreheads of toddlers, and for comparison also on the foreheads of their parents, as they jointly played with toys. Analyses of the head camera views indicate visual experiences with profoundly different dynamic structures. The toddler view often consists of a single dominating object that is close to the sensors and thus that blocks the view of other objects such that individual objects go in and out of view. The adult view, in contrast, is broad and stable, with all potential targets continually in view. These differences may arise for several developmentally relevant reasons, including the small visuo-motor workspace of the toddler (short arms) and the engagement of the whole body when actively handling objects.
TL;DR: Verbal reports substantiated the conclusion that by age 4 some children can remember a novel problem sufficiently enough to recognize a solution and select that solution in anticipation of applying it to the problem in the future.
Abstract: Much of humans' success rests on foresight, the ability to predict what will happen or what is needed in the future. Surprisingly little is known about how this faculty develops. In three experiments (N = 170), 3- and 4-year-old children were presented with simple puzzles. Fifteen minutes later in a different room they were given the opportunity to secure a solution to take back to the puzzle. Only the older children performed above chance, whereas both age groups could solve the task in an instant condition. The same pattern of results emerged for another task involving selection of something to 'feed ' a puppet whose favorite food was initially unavailable. Control conditions suggest that temporal rather than spatial displacement influenced performance. Verbal reports substantiated the conclusion that by age 4 some children can remember a novel problem sufficiently enough to recognize a solution and select that solution in anticipation of applying it to the problem in the future.
TL;DR: It is found that children whose families were in the top wealth quintile or whose mothers had secondary education performed significantly better across almost all measures of cognitive and language development and had better linear growth compared with children of women in the lowest wealth quintiles or women with no education.
Abstract: Our objectives were to document and examine socioeconomic gradients across a comprehensive set of child development measures in a population living in extreme poverty, and to interpret these gradients in light of findings from the neuroscience literature We assessed a nationally representative sample of 3-6-year-old children (n = 1332) from 150 communities of Madagascar using standard tests of development We found that children whose families were in the top wealth quintile or whose mothers had secondary education performed significantly better across almost all measures of cognitive and language development and had better linear growth compared with children of women in the lowest wealth quintile or women with no education These differences between children of low and high socioeconomic position were greatest for receptive language, working memory, and memory of phrases The mean difference in the scores between children in the highest and lowest socioeconomic status categories doubled between age 3 and age 6, and the biggest gaps across socioeconomic position by age 6 were in receptive language and sustained attention Our results suggest that even within the context of extreme poverty, there are strong associations between family socioeconomic status and child development outcomes among preschool children, and that the language and executive function domains exhibit the largest gradients
TL;DR: The results show a higher desynchronization of the mu rhythm when infants observed a goal-directed action than when they observed a spatially similar non-goal-directed movement, which indicates that the MNS is functioning at this age.
Abstract: The Mirror Neuron System hypothesis stating that observed actions are projected onto the observer’s own action system assigns an important role to development, because only actions mastered by the observer can be mirrored. The purpose of the present study was to investigate whether there is evidence of a functioning mirror neuron system (MNS) in 8-month-old infants. High-density EEG was used to assess the mu rhythm desynchronization in an action observation task where the infants observed a live model. To reduce noise, ICA decompositions were used. The results show a higher desynchronization of the mu rhythm when infants observed a goal-directed action than when they observed a spatially similar non-goal-directed movement. The localizations of the sources are in agreement with those proposed by the MNS hypothesis. This indicates that the MNS is functioning at this age.
TL;DR: The findings suggest that a period of auditory deprivation has secondary effects related to general sequencing deficits, and that disturbances in sequence learning may at least partially explain why some deaf children still struggle with language following cochlear implantation.
Abstract: Deaf children with cochlear implants (CIs) represent an intriguing opportunity to study neurocognitive plasticity and reorganization when sound is introduced following a period of auditory deprivation early in development. Although it is common to consider deafness as affecting hearing alone, it may be the case that auditory deprivation leads to more global changes in neurocognitive function. In this paper, we investigate implicit sequence learning abilities in deaf children with CIs using a novel task that measured learning through improvement to immediate serial recall for statistically consistent visual sequences. The results demonstrated two key findings. First, the deaf children with CIs showed disturbances in their visual sequence learning abilities relative to the typically developing normal-hearing children. Second, sequence learning was significantly correlated with a standardized measure of language outcome in the CI children. These findings suggest that a period of auditory deprivation has secondary effects related to general sequencing deficits, and that disturbances in sequence learning may at least partially explain why some deaf children still struggle with language following cochlear implantation.
TL;DR: Results confirm and extend previous comparative and developmental data, supporting an inborn predisposition to attend to biological motion in humans.
Abstract: The present study addresses the hypothesis that detection of biological motion is an intrinsic capacity of the visual system guided by a non-species-specific predisposition for the pattern of vertebrate movement and investigates the role of global vs. local information in biological motion detection. Two-day-old babies exposed to a biological motion point-light display (depicting a walking hen) and a non-biological motion display (a rotating rigid object) preferentially looked at the biological display (Experiment 1). A new group of newborns showed themselves to be capable of discriminating, following habituation, a biological motion display from a spatially scrambled version of it (Experiment 2). However, a third group of newborns, at their first exposure to such displays, did not show any preference between them (Experiment 3). Results confirm and extend previous comparative and developmental data, supporting an inborn predisposition to attend to biological motion in humans. This ability is presumably part of an evolutionarily ancient and non-species-specific system predisposing animals to preferentially attend to other animals.
TL;DR: The results indicate that the rise in sensation seeking that occurs during adolescence is not accompanied by a deficit in executive function and therefore requires different intervention strategies from those for youth whose impulsivity is characterized by early signs of acting without thinking.
Abstract: Studies of brain development suggest that the increase in risk taking observed during adolescence may be due to insufficient prefrontal executive function compared to a more rapidly developing subcortical motivation system. We examined executive function as assessed by working memory ability in a community sample of youth (n = 387, ages 10 to 12 at baseline) in three annual assessments to determine its relation to two forms of impulsivity (sensation seeking and acting without thinking) and a wide range of risk and externalizing behavior. Using structural equation modeling, we tested a model in which differential activation of the dorsal and ventral striatum produces imbalance in the function of these brain regions. For youth high in sensation seeking, both regions were predicted to develop with age. However, for youth high in the tendency to act without thinking, the ventral striatum was expected to dominate. The model predicted that working memory ability would exhibit (1) early weakness in youth high in acting without thinking but (2) growing strength in those high in sensation seeking. In addition, it predicted that (3) acting without thinking would be more strongly related to risk and externalizing behavior than sensation seeking. Finally, it predicted that (4) controlling for acting without thinking, sensation seeking would predict later increases in risky and externalizing behavior. All four of these predictions were confirmed. The results indicate that the rise in sensation seeking that occurs during adolescence is not accompanied by a deficit in executive function and therefore requires different intervention strategies from those for youth whose impulsivity is characterized by early signs of acting without thinking.
TL;DR: It is reported that active, self-produced reaching experiences also increase infants' spontaneous orienting towards faces, while passive experiences do not affect orienting behavior.
Abstract: The developing infant learns about the physical and the social world by engaging with objects and with people. In the study reported here, we investigated the relationship between infants’ interactions with the physical and the social world. Three-month-old infants were trained for 2 weeks and experienced either actively manipulating objects themselves or passively having objects touched to their hands. Following active or passive experiences, spontaneous orienting towards faces and objects was compared between the trained groups and untrained 3- and 5-month-olds. It is known that the onset of reaching behavior increases infants’ interest in objects. However, we report that active, self-produced reaching experiences also increase infants’ spontaneous orienting towards faces, while passive experiences do not affect orienting behavior. Regression analyses provide evidence for a link between manual engagement and the development of orienting towards faces. Implications of orienting towards faces for the development of triadic interactions, joint attention, and social cognition in general are discussed.
TL;DR: It is found that young 3-year-old children inferred normativity without any normative language and without any pedagogical cues, suggesting that - in the absence of explicit normative language - young children interpret adult actions as normatively governed based mainly on the intentionality with which they are performed.
Abstract: Young children interpret some acts performed by adults as normatively governed, that is, as capable of being performed either rightly or wrongly. In previous experiments, children have made this interpretation when adults introduced them to novel acts with normative language (e.g. ‘this is the way it goes’), along with pedagogical cues signaling culturally important information, and with social-pragmatic marking that this action is a token of a familiar type. In the current experiment, we exposed children to novel actions with no normative language, and we systematically varied pedagogical and social-pragmatic cues in an attempt to identify which of them, if either, would lead children to normative interpretations. We found that young 3-year-old children inferred normativity without any normative language and without any pedagogical cues. The only cue they used was adult socialpragmatic marking of the action as familiar, as if it were a token of a well-known type (as opposed to performing it, as if inventing it on the spot). These results suggest that – in the absence of explicit normative language – young children interpret adult actions as normatively governed based mainly on the intentionality (perhaps signaling conventionality) with which they are performed.
TL;DR: These results provide evidence for two early developing systems of non-verbal numerical cognition: one that responds to small quantities as individual objects and a second that responses to large quantities as approximate numerical values.
Abstract: Behavioral research suggests two cognitive systems are at the foundations of numerical thinking: one for representing 1-3 objects in parallel and one for representing and comparing large, approximate numerical magnitudes. We tested for dissociable neural signatures of these systems in preverbal infants, by recording event-related potentials (ERPs) as 6-7.5 month-old infants (n = 32) viewed dot arrays containing either small (1-3) or large (8-32) sets of objects in a number alternation paradigm. If small and large numbers are represented by the same neural system, then the brain response to the arrays should scale with ratio for both number ranges, a behavioral and brain signature of the approximate numerical magnitude system obtained in animals and in human adults. Contrary to this prediction, a mid-latency positivity (P500) over parietal scalp sites was modulated by the ratio between successive large, but not small, numbers. Conversely, an earlier peaking positivity (P400) over occipital-temporal sites was modulated by the absolute cardinal value of small, but not large, numbers. These results provide evidence for two early developing systems of non-verbal numerical cognition: one that responds to small quantities as individual objects and a second that responds to large quantities as approximate numerical values. These brain signatures are functionally similar to those observed in previous studies of non-symbolic number with adults, suggesting that this dissociation may persist over vast differences in experience and formal training in mathematics.
TL;DR: It is shown that children with dyslexia have excellent phonetic discrimination based on formant transition duration, but poor phoneticdiscrimination based on envelope cues, which explains why phonetic Discrimination may be allophonic in developmental Dyslexia and suggest new avenues for the remediation of developmental dyslexi.
Abstract: Across languages, children with developmental dyslexia have a specific difficulty with the neural representation of the sound structure (phonological structure) of speech. One likely cause of their difficulties with phonology is a perceptual difficulty in auditory temporal processing (Tallal, 1980). Tallal (1980) proposed that basic auditory processing of brief, rapidly successive acoustic changes is compromised in dyslexia, thereby affecting phonetic discrimination (e.g. discriminating /b/ from /d/) via impaired discrimination of formant transitions (rapid acoustic changes in frequency and intensity). However, an alternative auditory temporal hypothesis is that the basic auditory processing of the slower amplitude modulation cues in speech is compromised (Goswami et al., 2002). Here, we contrast children's perception of a synthetic speech contrast (ba/wa) when it is based on the speed of the rate of change of frequency information (formant transition duration) versus the speed of the rate of change of amplitude modulation (rise time). We show that children with dyslexia have excellent phonetic discrimination based on formant transition duration, but poor phonetic discrimination based on envelope cues. The results explain why phonetic discrimination may be allophonic in developmental dyslexia (Serniclaes et al., 2004), and suggest new avenues for the remediation of developmental dyslexia.
TL;DR: Thresholds for all three tasks improved monotonically between 6 and 14 years of age, at which point they were adult-like, suggesting that the extrastriate mechanisms that integrate local motion cues over time and space take many years to mature.
Abstract: We used a staircase procedure to test sensitivity to (1) global motion in random-dot kinematograms moving at 4! and 18! s )1 and (2) biological motion Thresholds were defined as (1) the minimum percentage of signal dots (ie the maximum percentage of noise dots) necessary for accurate discrimination of upward versus downward motion or (2) the maximum percentage of noise dots tolerated for accurate discrimination of biological from non-biological motion Subjects were adults and children aged 6‐8, 9‐11, and 12‐14 years (n = 20 per group) Contrary to earlier research, results revealed a similar, long developmental trajectory for sensitivity to global motion at both slower and faster speeds and for biological motion Thresholds for all three tasks improved monotonically between 6 and 14 years of age, at which point they were adult-like The results suggest that the extrastriate mechanisms that integrate local motion cues over time and space take many years to mature
TL;DR: One hypothesis about the difference between noun and verb acquisition is examined, suggesting the advantage nouns have is not a function of grammatical form class but rather related to a word's imageability.
Abstract: Nouns are generally easier to learn than verbs (e.g., Bornstein, 2005; Bornstein et al., 2004; Gentner, 1982; Maguire, Hirsh-Pasek, & Golinkoff, 2006). Yet, verbs appear in children's earliest vocabularies, creating a seeming paradox. This paper examines one hypothesis about the difference between noun and verb acquisition. Perhaps the advantage nouns have is not a function of grammatical form class but rather related to a word's imageability. Here, word imageability ratings and form class (nouns and verbs) were correlated with age of acquisition according to the MacArthur-Bates Communicative Development Inventory (CDI) (Fenson et al., 1994). CDI age of acquisition was negatively correlated with words' imageability ratings. Further, a word's imageability contributes to the variance of the word's age of acquisition above and beyond form class, suggesting that at the beginning of word learning, imageability might be a driving factor.
TL;DR: In this article, the authors explored the extent and regional specificity of EEG desynchronization in the infant alpha frequency range (6-9 Hz) during action observation and execution in 14-month-old infants.
Abstract: There is increasing interest in neurobiological methods for investigating the shared representation of action perception and production in early development. We explored the extent and regional specificity of EEG desynchronization in the infant alpha frequency range (6–9 Hz) during action observation and execution in 14-month-old infants. Desynchronization during execution was restricted to central electrode sites, while action observation was associated with a broader desynchronization across frontal, central, and parietal regions. The finding of regional specificity in the overlap between EEG responses to action execution and observation suggests that the rhythm seen in the 6–9 Hz range over central sites in infancy shares certain properties with the adult mu rhythm. The magnitude of EEG desynchronization to action perception and production appears to be smaller for infants than for adults and older children, suggesting developmental change in this measure.
TL;DR: Across both experiments a number of factors could be identified that affect enumeration in the subitizing and the counting range differentially and support the assumption of two qualitatively different enumeration processes.
Abstract: Enumeration performance in standard dot counting paradigms was investigated for different age groups with typical and atypically poor development of arithmetic skills. Experiment 1 showed a high correspondence between response times and saccadic frequencies for four age groups with typical development. Age differences were more marked for the counting than the subitizing range. In Experiment 2 we found a discontinuity between subitizing and counting for dyscalculic children; however, their subitizing slopes were steeper than those of typically developing control groups, indicating a dysfunctional subitizing mechanism. Across both experiments a number of factors could be identified that affect enumeration in the subitizing and the counting range differentially. These differential patterns further support the assumption of two qualitatively different enumeration processes.