Reasoning about knowledge: Children’s evaluations of generality and verifiability

In a series of experiments, we examined 3- to 8-year-old children’s (N = 223) and adults’ (N = 32) use of two properties of testimony to estimate a speaker’s knowledge: generality and verifiability. Participants were presented with a “Generic speaker” who made a series of 4 general claims about “pangolins” (a novel animal kind), and a “Specific speaker” who made a series of 4 specific claims about “this pangolin” as an individual. To investigate the role of verifiability, we systematically varied whether the claim referred to a perceptually-obvious feature visible in a picture (e.g., “has a pointy nose”) or a non-evident feature that was not visible (e.g., “sleeps in a hollow tree”). Three main findings emerged: (1) young children showed a pronounced reliance on verifiability that decreased with age. Three-year-old children were especially prone to credit knowledge to speakers who made verifiable claims, whereas 7- to 8-year-olds and adults credited knowledge to generic speakers regardless of whether the claims were verifiable; (2) children’s attributions of knowledge to generic speakers was not detectable until age 5, and only when those claims were also verifiable; (3) children often generalized speakers’ knowledge outside of the pangolin domain, indicating a belief that a person’s knowledge about pangolins likely extends to new facts. Findings indicate that young children may be inclined to doubt speakers who make claims they cannot verify themselves, as well as a developmentally increasing appreciation for speakers who make general claims.     

The Changing Role of Gesture in Linguistic Development: A Developmental Trajectory and a Cross-Cultural Comparison Between British and Finnish Children

We studied how gesture use changes with culture, age and increased spoken language competence. A picture-naming task was presented to British (N = 80) and Finnish (N = 41) typically developing children aged 2–5 years. British children were found to gesture more than Finnish children and, in both cultures, gesture production decreased after the age of two. Two-year-olds used more deictic than iconic gestures than older children, and gestured more before the onset of speech, rather than simultaneously or after speech. The British 3- and 5-year-olds gestured significantly more when naming praxic (manipulable) items than non-praxic items. Our results support the view that gesture serves a communicative and intrapersonal function, and the relative function may change with age. Speech and language therapists and psychologists observe the development of children’s gestures and make predictions on the basis of their frequency and type. To prevent drawing erroneous conclusions about children’s linguistic development, it is important to understand developmental and cultural variations in gesture use.     

An own-age bias in age estimation of faces

IntroductionAge estimation performances may be influenced by group biases.ObjectiveThis study investigated whether we are more accurate at estimating the age of people from one's own-age than the age of younger or older people.MethodChildren, young and older adults’ performances at estimating both in-group and out-group faces were compared.ResultsA significant “Age of participants” × “Age of face stimuli” interaction was revealed. Moreover, the age of children's faces was more accurately estimated than the age of young and older adults’ faces by the three groups of participants.ConclusionThe present results revealed the occurrence of an own-age bias for children, young and older adults in age estimation. Several explanations to this own-age effect are discussed.     

Beside the point: Mothers’ head nodding and shaking gestures during parent–child play

Understanding the context for children's social learning and language acquisition requires consideration of caregivers’ multi-modal (speech, gesture) messages. Though young children can interpret both manual and head gestures, little research has examined the communicative input that children receive via parents’ head gestures. We longitudinally examined the frequency and communicative functions of mothers’ head nodding and head shaking gestures during laboratory play sessions for 32 mother–child dyads, when the children were 14, 20, and 30 months of age. The majority of mothers produced head nods more frequently than head shakes. Both gestures contributed to mothers’ verbal attempts at behavior regulation and dialog. Mothers’ head nods primarily conveyed agreement with, and attentiveness to, children's utterances, and accompanied affirmative statements and yes/no questions. Mothers’ head shakes primarily conveyed prohibitions and statements with negations. Changes over time appeared to reflect corresponding developmental changes in social and communicative dimensions of caregiver–child interaction. Directions for future research are discussed regarding the role of head gesture input in socialization and in supporting language development.     

Remembering kinds: new evidence that categories are privileged in children's thinking

What are the representations and learning mechanisms that underlie conceptual development? The present research provides evidence in favor of the claim that this process is guided by an early-emerging predisposition to think and learn about abstract kinds. Specifically, three studies (N = 192) demonstrated that 4- to 7-year-old children have better recall for novel information about kinds (e.g., that dogs catch a bug called “fep”) than for similar information about individuals (e.g., that a particular dog catches a bug called “fep”). By showing that children are particularly likely to retain information about kinds, this work not only provides a first empirical demonstration of a phenomenon that may be key to conceptual development but also makes it apparent that young children’s thinking is suffused with abstractions rather than being perceptually-based and concrete.     

The impact of object type on the spatial analogies in Korean preschoolers

We tested young children’s spatial reasoning in a match-to-sample task, manipulating the objects in the task (abstract geometric shapes, line drawings of realistic objects, or both). Korean 4- and 5-year-old children (N = 161) generalized the target spatial configuration (i.e., on, in, above) more easily when the sample used geometric shapes and the choices used realistic objects than the reverse (i.e., realistic-object sample to geometric-shape choices). With within-type stimuli (i.e., sample and choices were both geometric shapes or both realistic objects), 5-year-old, but not 4-year-old, children generalized the spatial relations more easily with geometric shapes than realistic objects. In addition, children who knew more locative terms (e.g., “in”, “on”) performed better on the task, suggesting a link to children’s spatial vocabulary. The results demonstrate an advantage of geometric shapes over realistic objects in facilitating young children’s performance on a match-to-sample spatial reasoning task.     

Early Gesture Provides a Helping Hand to Spoken Vocabulary Development for Children with Autism,Down Syndrome,and Typical Development

Typically developing (TD) children refer to objects uniquely in gesture (e.g., point at a cat) before they produce verbal labels for these objects (“cat”). The onset of such gestures predicts the onset of similar spoken words, showing a strong positive relation between early gestures and early words. We asked whether gesture plays the same door-opening role in word learning for children with autism spectrum disorder (ASD) and Down syndrome (DS), who show delayed vocabulary development and who differ in the strength of gesture production. To answer this question, we observed 23 18-month-old TD children, 23 30-month-old children with ASD, and 23 30-month-old children with DS 5 times over a year during parent–child interactions. Children in all 3 groups initially expressed a greater proportion of referents uniquely in gesture than in speech. Many of these unique gestures subsequently entered children’s spoken vocabularies within a year—a pattern that was slightly less robust for children with DS, whose word production was the most markedly delayed. These results indicate that gesture is as fundamental to vocabulary development for children with developmental disorders as it is for TD children.     

Three-year-olds’ memory for a person met only once at the age of 12 months: Very long-term memory revealed by a late-manifesting novelty preference

This study examined three-year-olds’ verbal and non-verbal memory for a person met only once after a 28 month interval. Children in the Test group (N = 50) had participated in an earlier experiment at our lab at the age of 12 months where they met one of two possible experimenters. At this past event half of the children were tested by one, the other half by the other experimenter. At the follow-up, run by a naïve experimenter, the children were shown two videos from the original experiment in a visual paired comparison task: One with the specific experimenter testing them at the original visit (the Target) and one of the other experimenter (the Foil), with whom they had no experience. When explicitly asked, the children’s responses did not differ from chance. However, eye-tracking data revealed a late-manifesting novelty preference for the “Foil” person indicating memory for the “Target” person met once before.     

Barriers and facilitators of bicycle helmet use among children and their parents

Despite the fact that bicycle helmet use protects against head injuries, helmet use rate is still low even in countries with high concern for traffic safety. Earlier research shows that helmet use declines with age and that helmet use is low especially among teenagers. The aim of the present study was to investigate barriers and facilitators of helmet use among primary and secondary school pupils and their parents. Identical surveys were conducted among school children (n = 235) and their parents (n = 106). Children’s and adults’ responses concerning cycling, helmet use, helmet ownership, risk assessment and barriers and facilitators were compared and separate regression analyses conducted. Helmet use rate was lower among pupils than adults and they scored higher in most of the barrier items. The results of regression analyses showed that among children, age, gender, barriers and facilitators predicted helmet use while among adults only frequency of cycling and barriers were related to helmet use. Among children, the strongest correlates of not using a helmet were the belief of not needing a helmet and wish to use a cap or a hat instead. Having a helmet wearing as a habit and feeling safer were the strongest correlates of using helmet. Among adults, the strongest correlates of not using a helmet were “helmet looks ridiculous”, “just going to short trip” and riding close to home while the strongest correlate of using a helmet was the habit of helmet use. It was concluded that targeting the barriers in helmet wearing campaigns might work better both among children and adults than emphasising the benefits at least among Norwegian child and adult cyclists.     

Infant twins’ social interactions with caregivers and same-age siblings

The study of twin behavior offers the opportunity to study differential patterns of social and communicative interactions in a context where the adult partner and same-age peer are equally familiar. We investigated the development of social engagement, communicative gestures, and imitation in 7- to 25-month-old twins. Twin dyads (N = 20 pairs) participated in 10-min, semi-structured play sessions, with the mother seated in a chair completing paperwork for half the session, and on the floor with her children for the other half. Overall, twins engaged more with their mothers than with their siblings: they showed objects and imitated speech and object use more frequently when interacting with their mothers than with their siblings. When the mother was otherwise engaged, the twins played with toys separately, observed each other's toy play, or were unengaged. These results demonstrate that adult scaffolding of social interactions supports increased communicative bids even in a context where both familiar peers and adults are available as communicative partners.     

Do Children Understand Iconic Gestures About Events as Early as Iconic Gestures About Entities?

Children can understand iconic co-speech gestures that characterize entities by age 3 (Stanfield et al. in J Child Lang 40(2):1–10, 2014; e.g., “I’m drinking” \(+\) tilting hand in C-shape to mouth as if holding a glass). In this study, we ask whether children understand co-speech gestures that characterize events as early as they do so for entities, and if so, whether their understanding is influenced by the patterns of gesture production in their native language. We examined this question by studying native English speaking 3- to 4 year-old children and adults as they completed an iconic co-speech gesture comprehension task involving motion events across two studies. Our results showed that children understood iconic co-speech gestures about events at age 4, marking comprehension of gestures about events one year later than gestures about entities. Our findings also showed that native gesture production patterns influenced children’s comprehension of gestures characterizing such events, with better comprehension for gestures that follow language-specific patterns compared to the ones that do not follow such patterns—particularly for manner of motion. Overall, these results highlight early emerging abilities in gesture comprehension about motion events.     

Gestures convey substantive information about a child’s thoughts to ordinary listeners

The gestures that spontaneously occur in communicative contexts have been shown to offer insight into a child’s thoughts. The information gesture conveys about what is on a child’s mind will, of course, only be accessible to a communication partner if that partner can interpret gesture. Adults were asked to observe a series of children who participated ‘live’ in a set of conservation tasks and gestured spontaneously while performing the tasks. Adults were able to glean substantive information from the children’s gestures, information that was not found anywhere in their speech. ‘Gesture-reading’ did, however, have a cost – if gesture conveyed different information from speech, it hindered the listener’s ability to identify the message in speech. Thus, ordinary listeners can and do extract information from a child’s gestures, even gestures that are unedited and fleeting.     

The Moro reaction: More than a reflex,a ritualized behavior of nonverbal communication

ObjectiveTo propose a phylogenetic significance to the Moro reflex which remains unexplained since its publication in 1918 because both hands are free at the end of the gesture.MethodAmong the 75 videos of healthy term newborns we have filmed in a research project on antenatal education to parenthood, we describe a sequence that clearly showed the successive movements of the Moro reflex and we report the occurrence of this reflex in the videos that were recorded from Time 0 of birth defined as the moment that lies between the birth of the thorax and the pelvis of the infant.ResultsThe selected sequence showed the following succession of the newborn’s actions: quick extension-adduction of both arms, the orientation of the body, head and eyes towards a human person, and full extension-abduction of both arms with spreading of the fingers, crying and a distressed face. There were 13 Moro reflexes between 2 and 14 s from Time 0 of birth. We found a significant association between the occurrence of the Moro reflex and the placement of the newborn at birth in supine position on the mother’s abdomen (p = 0.002).DiscussionThe quick extension-adduction of both arms which started the sequence may be considered as a startle reflex controlled by the neural fear system and the arm extension-adduction which followed as a Moro reflex. The characteristics of all Moro reflexes were those of ritualization: amplitude, duration, stereotype of the gestures. This evolutionary process turns a physiological behavior, grasping in this case, to a non-verbal communicative behavior whose meaning is a request to be picked up in the arms. The gestures associated with the Moro reflex: crying and orientation of the body, head, and eyes towards a human person, are gestures of intention to communicate which support our hypothesis. The neural mechanism of the Moro reaction probably involves both the fear and the separation-distress systems.ConclusionThis paper proposes for the first time a phylogenetic significance to the Moro reflex: a ritualized behavior of nonverbal communication. Professionals should avoid stimulating the newborns’ fear system by unnecessarily triggering Moro reflexes. Antenatal education should teach parents to respond to the Moro reflexes of their newborn infant by picking her up in their arms with mother talk.     

Rhythmic ostensive gestures: How adults facilitate infants’ entrance into early triadic interactions

For decades, the literature on the emergence of triadic interactions considers the end of the first year of life as the time when children become able to communicate with others intentionally about a referent. Prior to that, children only relate in dyads, either with someone else or with an object. However, several researchers claim that referents are not naturally given in human communication and that they need to be established in interaction with others.In this study, we focus on earlier triadic interactions initiated by adults, when young babies still require an adult to bring the material world within their reach. In these early triadic interactions, ostensive gestures (with the object in the hand) are one of the first means of enabling the establishment of shared reference. Such gestures are easier to understand since sign (gesture) and referent (object) coincide. We conducted a longitudinal study with 6 babies filmed at 2, 3 and 4 months old in interaction with their mothers and a sounding object (a maraca). We analyzed different communicative initiatives by the adult and the child’s responses.The results show that children come to understand the adult’s communicative intention gradually through interaction. Adults include children in organized communicative “niches” based on ostensive actions, both through ostensive gestures and demonstrations of the use of the object. Consequently, the first shared understandings between adult and child take place around the object and its uses. Rhythm is a powerful tool used to structure the interaction. Eventually, adults provide space to children to actively interact with the sounding object themselves. These results highlight the importance of considering ostensive actions as a communicative tool that favors joint attention and action. They also bring some light to the interdependence between a child who actively perceives and acts, and the structured situation that the adult organizes for them.     

The relationship between computer-game preference,gender, and mental-rotation ability

This study examined how computer-game preference relates to mental-rotation test (MRT) performance and to gender differences. Subjects were 861 German secondary-school children (mean age = 14.67; range 10–20 years). Latent class analysis with the data of a computer-game preference scale revealed three types of players: “non-players”, “action-and-simulation game players” and “logic-and-skill-training game players”. Large gender differences were found with respect to class assignment. More females than males were found in the “logic-and-skill-training game player” class (82.9%) and in the class of “non-players” (81.9%). Males in contrast were overrepresented (81.7%) in the class of “action-and-simulation game players”. As expected, males on average outperformed females in mental-rotation test performance (d = 0.63). Furthermore, ANOVA results indicated mean differences in mental-rotation ability between action-and-simulation players and non-players (partial η² = .01) as well as age differences (partial η² = .04). With boys, non-players on average had lower MRT scores than action-and-simulation game players. For females, computer-game preference was unrelated to MRT performance. Results are discussed within a nature–nurture-interactionist framework of gender differences in spatial abilities.     

Measurement and comparative analysis of driver’s perception–reaction time to green phase at the intersections with and without a countdown timer

This paper proposes a method based on digital image processing for measuring drivers’ perception–reaction time (PRT) to the green phase. The detection of the onset of a green signal was based on the RGB color model. The detection of the start of the vehicle was based on the frame difference. The driver’s perception–reaction time was equal to the difference between the frame of the onset of the green signal and the frame of the start of the vehicle divided by the video frame rate. Drivers’ PRT with and without a countdown timer were comparatively analyzed. First, the means and variances of drivers’ PRT with a timer and without a timer were compared. Second, Normal, Lognormal, Gamma and Weibull distributions were used to fit the PRT data. Third, the fuzzy c-means clustering was utilized for PRT classification and comparison. The results show that the method for measuring drivers’ PRT based on digital image processing was effective. The drivers’ PRT was decreased from 2.12 s to 1.48 s with countdown signals. Weibull distribution appeared to best fit the PRT with No-Timer and Lognormal distribution appeared to best fit the PRT with Timer. The PRT data were classified into three groups: “Fast”, “Moderate” and “Slow”. Clustering centers without Timer were 1.16 s, 2.47 s and 3.98 s respectively. Clustering centers with Timer were 0.95 s, 1.64 s and 2.70 s respectively. The clustering centers can be regarded as reference values of drivers’ starting response for microscopic traffic simulation software.     

儿童手势及其与学习的关系

手势是在交流或认知过程中产生的、不直接作用于物体的手部运动, 具有具体性和抽象性。其分类主要从手势的来源、手势的内容、手势的意图及手势和言语的匹配性等角度进行划分。不同类型手势在出现时间及发展趋势上存在差异。手势在儿童词汇学习、言语表达、数学问题解决、空间学习及记忆等方面起促进作用, 但对言语理解的影响未得出一致结论。未来可关注不同类型手势与儿童认知发展的关系及对比不同来源手势在各学习领域的优势情况。     

Changes in cannabis use in emerging adulthood: The influence of peer network,impulsivity, anxiety and depression

IntroductionCannabis is the most commonly used illicit drug with the highest prevalence reported among 15- to 24-year-olds. This specific period of emerging adulthood constitutes a critical age for substance use and for future consumption. Cannabis use patterns change during college or university and the post-college transition; users are at greater risk of adverse health outcomes (especially if they start or maintain a pattern of frequent use).ObjectivesThe overall aim of this study was to highlight psychological and relational factors that might be associated with changes (including cessation and fluctuation) in cannabis use during this specific period, separately for males and females.MethodsThe subjects were 682 first-year college students (69.94% of female), aged between 18 and 25 years (M = 18.59 years, SD = 1.56). Four groups were formed according to cannabis consumption: “non-users” (54.64%), “desisting users” (14.04%), “fluctuating users” (16.23%), and “persistent users” (15.07%). A self-report questionnaire was administered to evaluate prevalence, frequency and trajectory of use, number of peer cannabis users, alcohol use, impulsivity, anxiety (trait and social) and depression.ResultsFemales appear more sensitive to the romantic partner's consumption than males. For both sexes, having more friends who use cannabis appears to be a determinant. Depression and anxiety were not related to changes in cannabis use. Impulsivity is a significant factor for the maintenance of cannabis use in emerging adulthood, with higher lack of premeditation for males and higher sensation seeking for females among fluctuating and persistent users.ConclusionsResults are discussed in terms of maintenance of use and the spiral of consumption, including clinical implications for prevention and interventions.     

Indian mate preferences: Continuity,sex differences,and cultural change across a quarter of a century

Expressed mate preferences provide unique windows into evolved mating psychology. The current study used two research instruments—one ranking and one rating procedure—to examine mate preferences in India. We compared modern Indians (n = 536) with a more modest Indian sample studied a quarter of a century earlier (n = 105) to test the hypothesis that sex-specific mate preferences—as hypothesized by parental investment theory—would persist during this time period. Mate preferences for mutual attraction and love remained important and invariant over time, despite India’s history of arranged marriages. Sex differences in mate preferences for cues to fertility (youth, physical attractiveness) and resources (good financial prospects, social status) remained relatively invariant over time. Several changes in mate preferences emerged, including a greater preference for mates who are “creative and artistic,” “ambitious and industrious,” and “a good cook and housekeeper” for both sexes. Despite cultural changes in India over the past 25 years, evolved mate preferences have persisted during this time period. Discussion highlights limitations of this research.     

Time Points: A Gestural Study of the Development of Space–Time Mappings

Human languages typically employ a variety of spatial metaphors for time (e.g., “I'm looking forward to the weekend”). The metaphorical grounding of time in space is also evident in gesture. The gestures that are performed when talking about time bolster the view that people sometimes think about regions of time as if they were locations in space. However, almost nothing is known about the development of metaphorical gestures for time, despite keen interest in the origins of space–time metaphors. In this study, we examined the gestures that English‐speaking 6‐to‐7‐year‐olds, 9‐to‐11‐year‐olds, 13‐to‐15‐year‐olds, and adults produced when talking about time. Participants were asked to explain the difference between pairs of temporal adverbs (e.g., “tomorrow” versus “yesterday”) and to use their hands while doing so. There was a gradual increase across age groups in the propensity to produce spatial metaphorical gestures when talking about time. However, even a substantial majority of 6‐to‐7‐year‐old children produced a spatial gesture on at least one occasion. Overall, participants produced fewer gestures in the sagittal (front‐back) axis than in the lateral (left‐right) axis, and this was particularly true for the youngest children and adolescents. Gestures that were incongruent with the prevailing norms of space–time mappings among English speakers (leftward and backward for past; rightward and forward for future) gradually decreased with increasing age. This was true for both the lateral and sagittal axis. This study highlights the importance of metaphoricity in children's understanding of time. It also suggests that, by 6 to 7 years of age, culturally determined representations of time have a strong influence on children's spatial metaphorical gestures.