Motor Development During the First Year: A Comparative Study

This investigation of the motor development characteristics of Brazilian infants during the 1st year of postnatal life compared the findings with those of a widely used U.S. sample (N. Bayley, 1993). Analysis of the 12 monthly assessments indicated that Brazilian infants' scores increased with age, with the greatest increase occurring over the first 8 months. As a general comparison, the results are similar to the U.S. patterns of development. However, the Brazilian sample exhibited mean scores significantly lower than the U.S. sample's in the 3rd, 4th, and 5th months. More specific analyses indicated that the difference within these months was on tasks of sitting and grasping. Possible explanations for the differences focus on variations in child-rearing practices and the influence of biological maturation in early movement behaviors.     

Bernstein's Theory of Movement Behavior: Historical Development and Contemporary Relevance

The traditional concept of cerebral dominance relies for support on the facts of handedness and the association of propositional speech with the leading hemisphere. This is regarded as evidence for specialization but not that the hemispheres are involved in an unchanging dominance relationship. The fact that the corpus callosum forms a bridge between the hemispheres means that they are not isolated units and that one may work through the other to control the functions of the limbs. Control however may be switched as the tasks demand the respective specializations of each hemisphere.     

Development of Bimanual Skill: The Search for Stable Patterns of Coordination

In 2 experiments, dynamic systems theory predictions concerning intrinsic dynamics and variability of bimanual coordination were examined at different developmental stages. In Experiment 1, ten 4-, 6-, 7-, 8-, and 10-year-old children and adults performed unimanual dominant, unimanual nondominant, and bimanual continuous circle drawing. All tasks were performed at the participants' preferred rate, size, and mode of coordination. The 4-, 6-, and 7-year-old children produced larger circles with longer durations than those of the 8- and 10-year-olds and the adults. That finding demonstrates that younger children display different intrinsic dynamics than older children and adults. The 4-, 6-, and 7-year-old children also displayed more variability in bimanual coordination (more time in less stable patterns of coordination, higher standard deviation in relative phase) and produced more transitions between coordination patterns than the 8- and 10-year-olds and the adults. In Experiment 2, the same participants performed bimanual circles at increasing rates. Consistent with predictions of the HKB model (H. Haken, J. A. S. Kelso, & H. Bunz, 1985), the number of transitions decreased as speed increased. Some support was found for the notion that age-related variables of attention and rate contribute to the increased variability in young children's bimanual coordination.     

Increased Jump Height with an External Focus Due to Enhanced Lower Extremity Joint Kinetics

Sensorimotor abilities are crucial for performance in athletic, military, and other occupational activities, and there is great interest in understanding learning in these skills. Here, behavioral performance was measured over three days as twenty-seven participants practiced multiple sessions on the Nike SPARQ Sensory Station (Nike, Inc., Beaverton, Oregon), a computerized visual and motor assessment battery. Wrist-worn actigraphy was recorded to monitor sleep–wake cycles. Significant learning was observed in tasks with high visuomotor control demands but not in tasks of visual sensitivity. Learning was primarily linear, with up to 60% improvement, but did not relate to sleep quality in this normal-sleeping population. These results demonstrate differences in the rate and capacity for learning across perceptual and motor domains, indicating potential targets for sensorimotor training interventions.     

Exploration and Selection of Intralimb Coordination Patterns in 3-Month-Old Infants

Through the exploration of their own capacities and the selection of adaptive responses, infants learn new motor solutions. Using a conjugate reinforcement mobile procedure, previous researchers have repeatedly shown that infants increase their leg kick frequency to control a mobile that is connected to their ankles. That traditional experimental design allows multiple motor solutions to the task and therefore provides limited information about the infants' capacity to explore and select specific motor solutions. The author designed a new experimental procedure to study infants' capacity to discover and adopt specific motor solutions. The new, constraining mobile reinforcement procedure requires a specific motor response and therefore the development of a more finely tuned perception—action map than has previously been experimentally demonstrated. To gain reinforcement from the mobile, infants had to produce a coordinated hip and knee extension within the same leg. The results from the 13 infant participants showed that they were capable of increasing their frequency of coordinated movements to make the mobile move. Those results suggest that infants at the age of 89–106 days are sensitive to intralimb coordination task requirements and are capable of mapping their own limb dynamics to the environmental information.     

Causality and the categorisation of objects and events

The “Tower of London” puzzle was adapted to tablet PCs to be used as a clinical bedside test. “Iso-problems”, a specific class of problems, require identical moves but ball colours are permuted. Thus difficulty is the same even if the appearance is different. We wanted to determine the impact of these as yet little-studied tasks and hypothesised that there may be a learning effect specific to them (the “iso-effect”). We interspersed a set of six iso-problems within one selection of 22 tasks and analysed problem solving by 81 healthy adults (mean age 41.6 years). Participants showed learning across iso-problems (less time, fewer moves, increasingly efficient solutions). This effect was distinct from general learning, as was obvious from comparison with a series of non-isomorphic tasks. However, participants seem not to be aware of solving such problems. This “iso-effect” may be related to implicit memory, a domain that so far has not been assessed using the Tower of London.     

When modesty wins: Impression management through modesty,political skill,and career success—a two-study investigation

The purpose of this research is to investigate the effect of employees' upward self-presentation through modesty and political skill on their subsequent career success. Study 1 used a predictive design over a 3 year period with 141 employees, controlling for age, gender, and self-esteem. Political skill positively moderated the relationship between employees' upward modesty and career success (attained position, career satisfaction) after 3 years. Study 2 (n = 132 employees) provided construct validation, demonstrating high discriminant validity of the impression management through modesty scale used in Study 1 with a trait-modesty scale, thus attenuating rival explanations of the findings in Study 1. Implications, limitations, and future directions for research are discussed.     

Effects of Item Difficulty on the Retrieval of Solutions during Cognitive Skill Acquisition: Age Differences

ABSTRACT

In cognitive skill learning, shifts to better strategies for obtaining solutions often occur while associations between problems and solutions are being strengthened. In two skill learning experiments, we examined the effects of item difficulty on the retrieval of solutions and the learning of problem–solution associations in younger and older adults. The results of both experiments demonstrated an ‘easy effect’ in both younger and older adults, such that the retrieval of solutions as well recognition memory for problems was best for the easier items. In addition, a ‘hard effect’ was found in younger adults, but not in older adults, whereby the retrieval of solutions as well as recognition memory for problems was better for harder items than for medium-difficulty items. The finding that increased computational demands at the item level delayed item memorization and the retrieval of solutions in older adults but not younger adults is consistent with a general-resources account of age-related differences in skill learning.     

Embodied cognition and skilled health behaviour

The present research examines health persuasion from an embodied cognition perspective by proposing that engaging the motor system during presentation of a health message will lead individuals to become more skilled at performing the prescribed behaviour. Participants watched a video on the importance of flossing while either imaging themselves flossing or imaging themselves flossing while minimally engaging the motor system (i.e. touching a piece of floss). Females (but not males) who touched an individual floss while watching the video demonstrated better flossing skills 1 week later. Over time, participants (both males and females) who engaged the motor system also developed more accessible attitudes and had a stronger relationship between their perceived flossing efficacy and actual flossing skill. Implications for the theories of embodied cognition and health interventions are discussed.