General Cognitive Abilities and Psychosocial Development in Children and Adolescents Having a Co-Twin with Down Syndrome.

OBJECTIVE: To examine the general cognitive and psychosocial development in children and adolescents having a co-twin with Down syndrome. STUDY DESIGN: A case control study with an individually matched control group was conducted. Participants included families with twins discordant for Down syndrome as well as with typically developing twins. The group of unaffected co-twins aged 4-16 years was compared with a control group of typically developing twins in terms of general cognitive abilities, behavioral problems, and prosocial behavior. The age and sex and the sex composition of the twins were individually matched. The Sijnders-Oomen nonverbal intelligence test was applied to assess children's IQ, and parents completed the Strength and Difficulties Questionnaire. RESULTS: The unaffected co-twins did not differ from typically developing twins with respect to their IQ. Concerning the psychosocial development, significantly heightened values in unaffected co-twins twins were only obtained for the conduct problems scale (P = .01; r = 0.45), neither for the total difficulties score nor for the other behavioral problem scales significant differences were found. CONCLUSIONS: The general cognitive development of the unaffected co-twin of children with Down syndrome is not affected by the presence of their Down syndrome twin. Unaffected co-twins showed increased conduct problems, which is most pronounced in the younger children.

A model's natural group membership affects over-imitation in 6-year-olds.

The phenomenon of "over-imitation"-the copying of causally irrelevant actions-has influenced research of the past decade. Yet, the mechanisms underlying and factors affecting over-imitation are still under debate. This study aimed to contribute to this debate by investigating the role of the model's natural group membership in children's tendency to imitate irrelevant actions using a two-phase design. In Phase 1, 6-year-olds (N = 64) observed either an in-group model or an out-group model presenting a sequence of irrelevant actions, with only the last action bringing about the goal (target action) and retrieving a token. In Phase 2, the alternative model-the one that children had not seen in Phase 1-retrieved the token by performing the target action only. After the presentation in each phase, children were given the chance to retrieve the token themselves. Results indicated that children imitated the irrelevant actions to comparable levels from both models in Phase 1. In Phase 2, in contrast, over-imitation declined in children who observed the in-group model being successful with the target action only but not in children who observed the out-group model do so. Thus, children adapted their imitative behavior after observing the model of their own cultural group demonstrating a more efficient strategy. These findings speak for an integration of both social and instrumental accounts to explain the phenomenon of over-imitation.

[The Effect of a Short-Term Mindfulness Program on Memory Performance in School-Aged Children]. / Die Wirkung achtsamkeitsbasierter Kurzzeitinterventionen auf das Kurz- und Langzeitgedächtnis im Grundschulalter.

The Effect of a Short-Term Mindfulness Program on Memory Performance in School-Aged Children A one-week mindfulness-based intervention designed to improve 8- to 10-year-old children's memory performance was investigated. Seventy-three children were quasi-randomly assigned either to one of two mindfulness-based intervention groups (breathing meditation or yoga), or to an active control group. The sessions were held on six consecutive days. Prior to intervention and after completing the intervention, children's short-term and long-term memory performance were assessed. In confirmation of prior studies, breathing meditation and yoga showed positive effects on memory performance when compared with the control group. Moreover, differences in the effectiveness of breathing meditation and yoga were found: While both interventions had comparable effects on long-term memory, only breathing meditation showed improvements in short-term memory performance. The present study provides valuable evidence on the effectiveness of meditation on cognitive functions in childhood and shows that school-aged children can already benefit from short-term meditation programs.

Lifespan development of the bilateral deficit in a simple reaction time task.

Performing an action at a maximum speed or with a maximum strength simultaneously with two limbs leads to a lower performance than the sum of unimanual performances. This phenomenon is known as bilateral deficit. There is some evidence that the bilateral deficit changes over the lifespan, in a way that children and older adults show lower deficits than young adults. Inverse developmental changes of childrens' and older adults' brain structures connecting both hemispheres, i.e., the corpus callosum, might importantly contribute to this phenomenon. The seemingly similar developments have been observed with different experimental protocols in the different age groups, respectively. To test for similarities and differences in changes of the bilateral deficit at critical periods of the lifespan development of bimanual actions, children, young adults, and older adults performed a simple reaction time task uni- and bimanually. Reaction times and the resulting bilateral deficit, as well as reaction time variability were analyzed. As expected, reaction times were different for the young adults between the uni- and the bimanual task. Children and older adults performed both conditions with similar reaction times. However, a difference in the direction of the %bilateral deficit occurred between the two age groups. The findings demonstrated an absence of the bilateral deficit for children, but not for younger and older adults.

Effects of short-term experience on anticipatory eye movements during action observation.

Recent studies have shown that anticipatory eye movements occur during both action observation and action execution. These findings strongly support the direct matching hypothesis, which states that in observing others' actions, people take advantage of the same action knowledge that enables them to perform the same actions. Furthermore, a connection between action experience and the ability to anticipate action goals has been proposed. Concerning the role of experience, most studies concentrated on motor experts such as athletes and musicians, whereas only few studies investigated whether motor programs can be activated by short-term experience. Applying a pre-post design, we examined whether short-term experience affects anticipatory eye movements during observation. Participants (N = 150 university students) observed scenes showing an actor performing a block stacking task. Subsequently, participants performed either a block stacking task, puzzles, or a pursuit rotor task. Afterward, participants were again provided with the aforementioned block stacking task scenes. Results revealed that the block stacking task group directed their gaze significantly earlier toward the action goals of the block stacking task during posttest trials, compared with Puzzle and pursuit rotor task groups, which did not differ from each other. In accordance with the direct matching hypothesis, our study provides evidence that short-term experience with the block stacking task activates task-specific action knowledge.

Development of spatial preferences for counting and picture naming.

The direction of object enumeration reflects children's enculturation but previous work on the development of such spatial preferences has been inconsistent. Therefore, we documented directional preferences in finger counting, object counting, and picture naming for children (4 groups from 3 to 6 years, N = 104) and adults (N = 56). We found a right-side preference for finger counting in 3- to 6-year-olds and a left-side preference for counting objects and naming pictures by 6 years of age. Children were consistent in their special preferences when comparing object counting and picture naming, but not in other task pairings. Finally, spatial preferences were not related to cardinality comprehension. These results, together with other recent work, suggest a gradual development of spatial-numerical associations from early non-directional mappings into culturally constrained directional mappings.

Perception and production of object-related grasping in 6-month-olds.

In this study, 6-month-olds' perception of an object-related human grasping action was compared with their level of grasping performance using a within-participants design. In the action perception task, infants were presented with the video of an actor's grasping movement toward an occluded target object. Subsequently, an expected and an unexpected final state of this grasping movement were presented simultaneously, and infants' looking times were measured. In the action production task, infants were presented with three graspable objects. Infants' grasping behavior was coded to be either palmar or thumb-opposite grasping. Results indicate that infants who were already able to perform a thumb-opposite grasp differentiated between the two final states in the action perception task by looking longer toward the unexpected final state. In contrast, infants who showed only palmar grasps looked equally long toward both final states. This finding supports the assumption that action perception and action control are already closely related in infants as young as 6 months.

The link between preschoolers' executive function and theory of mind and the role of epistemic states.

The aim of this study was to assess the specific relation between 3- to 6-year-olds' performance on a task measuring executive function (EF), the Dimensional Change Card Sort task (DCCS), and different developmental attainments in their theory of mind (ToM) by employing a battery of scaled ToM tasks that were comparable in task format and task demands. In addition, individual differences on the temperamental dimensions emotionality, activity, sociability, and shyness were assessed by parental rating. The main findings show that children's (N=195) performance on the DCCS related to their overall performance on the ToM scale but that this relation was specific to those ToM tasks that tap children's understanding of epistemic states such as knowledge access, diverse beliefs, and false beliefs regarding content and location. The relation between children's EF and overall ToM performance remained significant after controlling for age, sentence comprehension, child temperament, and parental education. Individual differences in child activity showed consistent negative relation to EF and ToM abilities. The findings point to a differential involvement of the various EF components in reasoning about different mental concepts.

Inferring the size of a goal object from an actor's grasping movement in 6- and 9-month-old infants.

The present study applied a preferential looking paradigm to test whether 6- and 9-month old infants are able to infer the size of a goal object from an actor's grasping movement. The target object was a cup with the handle rotated either towards or away from the actor. In two experiments, infants saw the video of an actor's grasping movement towards an occluded target object. The aperture size of the actor's hand was varied as between-subjects factor. Subsequently, two final states of the grasping movement were presented simultaneously with the occluder being removed. In Experiment 1, the expected final state showed the actor's hand holding a cup in a way that would be expected after the performed grasping movement. In the unexpected final state, the actor's hand held the cup at the side which would be unexpected after the performed grasping movement. Results show that 6- as well as 9-month-olds looked longer at the unexpected than at the expected final state. Experiment 2 excluded an alternative explanation of these findings, namely that the discrimination of the final states was due to geometrical familiarity or novelty of the final states. These findings provide evidence that infants are able to infer the size of a goal object from the aperture size of the actor's hand during the grasp.

The Development of Rational Imitation in 9- and 12-Month-Old Infants.

Studies on rational imitation have provided evidence for the fact that infants as young as 12 months of age engage in rational imitation. However, the developmental onset of this ability is unclear. In this study, we investigated whether 9- and 12-month-olds detect voluntary and implicit as well as nonvoluntary and explicit constraints in the head touch task. Three groups of infants watched video sequences, which displayed a person illuminating a lamp using the head. The hands of the model were either free, occupied by voluntarily holding a blanket, or nonvoluntarily restrained by being tied to the table. An additional control group of infants watched the model turning on the lamp by using the hand. Given that the majority of infants imitated the head touch when the model's hands were free, there was evidence for rational imitation in comparison to the condition in which the model's hands were tied to the table, but not in comparison to the condition in which the hands were occupied by holding a blanket. Nine-month-olds showed no differences in their behavior according to the condition. These findings clarify the onset of rational imitation by showing that 12-month-olds (but not 9-month-olds) take into account a situational constraint only when the constraint is nonvoluntary and explicit.

Means-End Behavior in Young Infants: The Interplay of Action Perception and Action Production.

In 2 experiments, the interplay of action perception and action production was investigated in 6-month-old infants. In Experiment 1, infants received 2 versions of a means-end task in counterbalanced order. In the action perception version, a preferential looking paradigm in which infants were shown an actor performing means-end behavior with an expected and an unexpected outcome was used. In the action production version, infants had to pull a cloth to receive a toy. In Experiment 2, infants' ability to perform the action production task with a cloth was compared to their ability to perform the action production task with a less flexible board. Finally, Experiment 3 was designed to control for alternative low-level explanations of the differences in the looking times toward the final states presented in Experiment 1 by only presenting the final states of the action perception task without showing the initial action sequence. Results obtained in Experiment 1 showed that in the action perception task, infants discriminated between the expected and the unexpected outcome. This perceptual ability was independent of their actual competence in executing means- end behavior in the action production task. Experiment 2 showed no difference in 6-month-olds' performance in the action production task depending on the properties of the support under the toy. Similarly, in Experiment 3, no differences in looking times between the 2 final states were found. The findings are discussed in light of theories on the development of action perception and action production.

Reversed effects of spatial compatibility in natural scenes.

Effects of spatial stimulus-response compatibility are often attributed to automatic position-based activation of the response elicited by a stimulus. Three experiments examined this assumption in natural scenes. In Experiments 1 and 2, participants performed simulated driving, and a person appeared periodically on either side of the road. Participants were to turn toward a person calling a taxi and away from a person carelessly entering the street. The spatially incompatible response was faster than the compatible response, but neutral stimuli showed a typical benefit for spatially compatible responses. Placing the people further in the visual periphery eliminated the advantage for the incompatible response and showed an advantage for the compatible response. In Experiment 3, participants made left-right joystick responses to a vicious dog or puppy in a walking scenario. Instructions were to avoid the vicious dog and approach the puppy or vice versa. Results again showed an advantage for the spatially incompatible response. Thus, the typically observed advantage of spatially compatible responses was reversed for dangerous situations in natural scenes.

Inter- versus intramodal integration in sensorimotor synchronization: a combined behavioral and magnetoencephalographic study.

Although the temporal occurrence of the pacing signal is predictable in sensorimotor synchronization tasks, normal subjects perform on-the-beat-tapping to an isochronous auditory metronome with an anticipatory error. This error originates from an intermodal task, that is, subjects have to bring information from the auditory and tactile modality to coincide. The aim of the present study was to illuminate whether the synchronization error is a finding specific to an intermodal timing task and whether the underlying cortical mechanisms are modality-specific or supramodal. We collected behavioral data and cortical evoked responses by magneto-encephalography (MEG) during performance of cross- and unimodal tapping-tasks. As expected, subjects showed negative asynchrony in performing an auditorily paced tapping task. However, no asynchrony emerged during tactile pacing, neither during pacing at the opposite finger nor at the toe. Analysis of cortical signals resulted in a three dipole model best explaining tap-contingent activity in all three conditions. The temporal behavior of the sources was similar between the conditions and, thus, modality independent. The localization of the two earlier activated sources was modality-independent as well whereas location of the third source varied with modality. In the auditory pacing condition it was localized in contralateral primary somatosensory cortex, during tactile pacing it was localized in contralateral posterior parietal cortex. In previous studies with auditory pacing the functional role of this third source was contradictory: A special temporal coupling pattern argued for involvement of the source in evaluating the temporal distance between tap and click whereas subsequent data gave no evidence for such an interpretation. Present data shed new light on this question by demonstrating differences between modalities in the localization of the third source with similar temporal behavior.

Encoding the goal of an object-directed but uncompleted reaching action in 6- and 9-month-old infants.

Infants start to interpret completed human actions as goal-directed in the second half of the first year of life. In a series of three studies, the understanding of a goal-directed but uncompleted action was investigated in 6- and 9-month-old infants using a preferential looking paradigm. Infants saw the video of an actor's reaching movement towards one of two objects. This reaching movement was only presented until the hand passed the midpoint between the starting position and the position of the target object. Subsequently, two final states of the reaching movement were presented simultaneously. In the plausible final state, the hand grasped the object to which the reaching movement was geared; in the implausible final state, the hand grasped the other object. In Studies 1 and 3, infants watched the actor from an allocentric perspective, and in Studies 2 and 3 from an egocentric perspective. Results indicate a discrimination of the two final states if the scene was presented from an allocentric perspective: both 6- and 9-month-olds looked longer at the implausible final state. This was not the case if infants saw the action from an egocentric perspective. The presented findings show that using this paradigm, 6-month-olds are already able to infer the goal of an uncompleted action without seeing the achievement of the goal itself. However, they encoded the goal of the reaching action only when it was presented from an allocentric perspective but not from an egocentric perspective.

The link between infant attention to goal-directed action and later theory of mind abilities.

Various studies have shown that infants in their first year of life are able to interpret human actions as goal-directed. It is argued that this understanding is a precondition for understanding intentional actions and attributing mental states. Moreover, some authors claim that this early action understanding is a precursor of later Theory of Mind (ToM) development. To test this, we related 6-month-olds' performance in an action interpretation task to their performance in ToM tasks at the age of 4 years. Action understanding was assessed using a modified version of the Woodward-paradigm (Woodward, 1999). At the age of 4 years, the same children were tested with the German version of the ToM scale developed by Wellman and Liu (2004). Results revealed a correlation between infants' decrement of attention to goal-directed action and their ability to solve a false belief task at the age of 4 years with no modulation by language abilities. Our results indicate a link between infant attention to goal-directed action and later theory of mind abilities.

Visual proprioception in the timing of movements: evidence from deafferentation.

The present study investigated the control of movements in two patients with severe somatosensory deafferentation by systematically manipulating the visual information about the produced movements. In a synchronization task requiring the production of finger taps in synchrony with a regular auditory signal, participants controlled their movements under full vision or when the sight of the effector was partially or completely occluded. Results demonstrated large effects of visual feedback on the synchronization performance in the deafferented patients. Although the patients' performance differed substantially from that of unimpaired controls under partial or no feedback, their performance was comparable under full vision, the latter suggesting a compensation of the somatosensory loss by visual monitoring.

The effect of sensory feedback on the timing of movements: evidence from deafferented patients.

The role of sensory feedback in the control of movements was investigated in two deafferented patients with complete loss of cutaneous touch and movement/position sense below the neck and two control groups of different ages. In a synchronized repetitive finger-tapping task in time with a regular auditory pacing signal, the deafferented participants showed a strong influence of extrinsic feedback. In contrast to controls who demonstrated a typical asynchrony between their taps and the pacing signal in all feedback conditions, the deafferented participants, with auditory feedback and visual monitoring, showed no asynchrony between finger taps and the pacing signal. These findings support the view that sensory information plays a crucial role in the anticipatory timing of movements.

The Relationship between Emotion Comprehension and Internalizing and Externalizing Behavior in 7- to 10-Year-Old Children.

The influence of internalizing and externalizing problems on children's understanding of others' emotions has mainly been investigated on basic levels of emotion comprehension. So far, studies assessing more sophisticated levels of emotion comprehension reported deficits in the ability to understand others' emotions in children with severe internalizing or externalizing symptoms. The aim of this study was to investigate the relation between emotion comprehension and interindividual differences, with a focus on internalizing and externalizing behavior in children aged 7-10 years from the general population. A sample of 135 children was tested for emotion understanding using the Test of Emotion Comprehension. Information on internalizing and externalizing behavior was assessed with the Child Behavior Checklist 4/18. Age, bilingual upbringing, and amount of paternal working hours were significant control variables for emotion comprehension. In contrast to prior research, overall level of emotion understanding was not related to externalizing symptoms and correlated positively with elevated levels of somatic complaints and anxious/depressed symptoms. In addition, and in line with previous work, higher levels of social withdrawal were associated with worse performance in understanding emotions elicited by reminders. The present results implicate not only an altered understanding of emotions among more specific internalizing symptoms, but also that these alterations occur already on a low symptom level in a community based sample.

Tom Is Not More Likely to Imitate Lisa Than Ying: The Influence of a Model's Race Indicated by Physical Appearance on Children's Imitation.

Recent research has shown that infants and young children up to the age of 5 years are more likely to imitate in-group members than out-group members. Cues like gender, race, age, and language are robust indicators for social categories and, thus, for group membership. Concerning imitation, research mainly focuses on language and accent, whereas race indicated by physical appearance is rarely investigated. Research has shown that the aforementioned factors served as indicators of group membership and influenced children's imitative behavior in such ways that the in-group member was more likely to be imitated. Nevertheless, the question arises how physical appearance of a person itself influences the imitative behavior. In this study, we investigated the effect of group membership (in-group vs. out-group) in 4-year-old children (N = 48) on children's imitative behavior. Children observed either an in-group or an out-group model (German vs. Chinese), defined by physical appearance only, which presented novel manual actions in four different tasks. After each presentation, children got the opportunity to imitate the target actions. Furthermore, children were either assigned to a live or a video condition to control for the influence of the presentation mode. Results indicated that 4-year-old children did not imitate the in-group model more often than the out-group model. Furthermore, there was no difference between the two presentation modes. Results were discussed on the basis of research on the in-group-out-group effect. We suggested that a pure difference in the model's physical appearance might not be sufficient to elicit an in-group-out-group effect.