The social cognition and perception-action literatures are largely separate, both conceptually and empirically. However, both areas of research emphasize infants' emerging abilities to use available information-social and perceptual information, respectively-for making decisions about action. Borrowing methods from both research traditions, this study examined whether 18-month-old infants incorporate both social and perceptual information in their motor decisions. The infants' task was to determine whether to walk down slopes of varying risk levels as their mothers encouraged or discouraged walking. First, a psychophysical procedure was used to determine slopes that were safe, borderline, and risky for individual infants. Next, during a series of test trials, infants received mothers' advice about whether to walk. Infants used social information selectively: They ignored encouraging advice to walk down risky slopes and discouraging advice to avoid safe slopes, but they deferred to mothers' advice at borderline slopes. Findings indicate that 18-month-old infants correctly weigh competing sources of information when making decisions about motor action and that they rely on social information only when perceptual information is inadequate or uncertain. Two sources of information are available to infants for making decisions about action: perceptual information generated by infants' own exploratory movements and social information offered by infants' parents and other people. An eager infant poised at the top of the stairs as mother screams "No!," a timid infant who is encouraged to attempt the daunting playground slide, a crawling infant whose parent's silence conveys that it is okay to roam, and a beginning walker reluctant to take steps into mother's open arms must decide whether to descend, slide, crawl, and walk on the basis of the available perceptual and social information.Sometimes perceptual and social cues are concordant, offering redundant information that specifies the way to act (e.g., when parents nod toward an inviting toy or say "No, no" toward a menacing dog). Other times, perceptual and social information are at odds, specifying opposing courses of action (e.g., when parents warn their toddlers to stay away from an empty street or encourage their infants to crawl onto the unfamiliar surface of a sandy beach). Discordant perceptual and social information is especially interesting because infants confront an interpretive challenge: They must decide how to weigh and integrate competing sources of information. In such situations, infants might assign priority to social information and defer to mothers' advice, regardless of their own perceptual assessment of the situation. Alternatively, infants might rely on perceptual information and ignore their mothers' social messages. A third possibility is that infants assess social and perceptual cues on a case-by-case basis, relying selectively on social information when perceptual cues leave them uncertain about how to act. On this last account, infan...

The content of mothers' emotional, verbal, and gestural communication to their infants was examined under conditions of potential physical risk in a laboratory motor task. Mothers encouraged and discouraged their 12‐ and 18‐month‐old infants to crawl or walk down a sloping walkway. Mothers expressed positive affect on nearly every trial. They rarely expressed purely negative affect in their faces and voices, even when discouraging. Instead, they discouraged infants with a mixture of positive and negative expressions. In both encourage and discourage conditions, mothers coupled their emotional messages with rich verbal and gestural information to elicit infants' attention, regulate their location, guide their actions, and describe the situation and potential consequences of their actions. The content of mothers' communication was attuned to infants' age and locomotor experience.

No abstract

Children with unilateral spastic cerebral palsy (USCP) have impairments in motor planning, impacting their ability to grasp objects. We examined the planning of digit position and force and the flexibility of the motor system in covarying these during object manipulation. Eleven children with a left hemisphere lesion (LHL), nine children with a right hemisphere lesion (RHL) and nine typically developing children (controls) participated in the study. Participants were instructed to use a precision grip with their dominant/less affected hand to lift and keep an object level, with either a left, centered or right center of mass (COM) location. Digit positions, forces, compensatory torque and object roll where measured. Although children with USCP generated a compensatory torque and modulated digit placement by lift-off, their index finger was either collinear or higher than the thumb, regardless of COM location, leading to larger rolls after lift-off especially for the RHL group. The findings suggest that while the kinetics of grasp control is intact, the kinematics of grasp control is impaired. This study adds to the understanding of the underlying mechanisms of anticipatory planning and control of grasp in children with USCP and may provide insights on how to improve hand function in children with USCP.

SYNOPSISObjectives. In 2 studies, we aimed to describe the content of mothers' verbal warnings to their young children and to investigate whether mothers modify their warnings based on the type of dangerous situation and children's age. Study 1. Mothers of 12-, 18-, and 24-month-olds reported in a telephone interview the words and phrases they would use to prevent their children from falling, touching dangerous objects, ingesting poisonous substances, and running away. The words "no," "don't," and "stop" were the most frequent warnings across ages. Mothers also used warnings to elicit their children's attention, regulate children's location, modify children's actions, and to highlight the properties and consequences of specific dangers. The content, diversity and complexity of mothers' warnings varied with children's age and the type of dangerous situation. Study 2. We observed mothers in the laboratory as they warned their 12-and 18-month-old children not to walk down 50°slopes. As in Study 1, mothers primarily relied on the words "no," "don't," and "stop," but again used warnings to elicit attention, regulate location, modify actions, and describe the danger. Mothers used more complex and diverse warnings with older versus younger children. Conclusions. Although simple warnings, such as "no," "don't," and "stop" hold privileged status at all ages, mothers express a rich array of warnings that are attuned to children's age and the dangers of the situation.