Movers and shakers of cognition:Hand movements, speech, task properties, and variability

Children move their hands to explore, learn and communicate about hands-on tasks. Their hand movements seem to be “learning” ahead of speech. Children shape their hand movements in accordance with spatial and temporal task properties, such as when they feel an object or simulate its movements. Their speech does not directly correspond to these spatial and temporal task properties, however. We aimed to understand whether and how hand movements' are leading cognitive development due to their ability to correspond to spatiotemporal task properties, while speech is unable to do so. We explored whether hand movements' and speech's variability changed with a change in spatiotemporal task properties, using two variability measures: Diversity indicates adaptation, while Complexity indicates flexibility to adapt. In two experiments, we asked children (4–7 years) to predict and explain about balance scale problems, whereby we either manipulated the length of the balance scale or the mass of the weights after half of the trials. In three out of four conditions, we found a change in Complexity for both hand movements and speech between first and second half of the task. In one of these conditions, we found a relation between the differences in Complexity and Diversity of hand movements and speech. Changes in spatiotemporal task properties thus often influenced both hand movements' and speech's flexibility, but there seem to be differences in how they did so. We provided many directions for future research, to further unravel the relations between hand movements, speech, task properties, variability, and cognitive development

Action-selection perseveration in young children:Advances of a dynamic model

This study presents an empirical test and dynamic model of perseverative limb selection in children of 14-, 24-, and 36-months old (N = 66 in total). In the experiment, children repeatedly grasped a spoon with a single hand. In two separate conditions, the spoon was presented either four times on their right side or four times on their left side. In both conditions, following this training, the spoon was presented on midline for two more trials. This setup enabled us to determine whether children's limb selection was influenced by their prior choices in the task (i.e., perseveration). Individual children's handedness was determined in a third condition consisting of nine object presentations (laterally or on midline). A dynamic model for limb selection is presented combining external input, motor memory, and preferences. The model was used to simulate the experiment and reproduced the results, including the age-related changes

Sensory processing in young children with visual impairments:Use and extension of the Sensory Profile

Background: Children with visual impairments (VI) are at risk for sensory processing difficulties. A widely used measure for sensory processing is the Sensory Profile (SP). However, the SP requires adaptation to accommodate for how children with VI experience sensory information. Aims: (1) To examine sensory processing patterns in young children with VI, (2) to develop VI-specific items to use in conjunction with the SP and to determine internal consistency and construct validity of these newly developed items, and (3) to examine the association between sensory processing and and emotional and behavioral problems. Methods: Twenty-six VI-specific items were added to the SP. The SP and these items were completed by caregivers of 90 children with VI between 3 and 8 years old. The Child Behavior Checklist (CBCL) was used to assess emotional and behavioral problems. Results: Three- to five-year-old children with VI have significantly more difficulties in three quadrants of the SP as compared to the norm group. Six- to eight-year-old children with VI have more difficulties in all quadrants. A reliable and valid VI-specific set of 15 items was established following psychometric evaluation. Age-related differences were found in the associations between the SP and CBCL. Conclusion: Although further validation is recommended, this evaluation of the VI-specific item set suggests it has the potential to be a useful measure for children with VI

Infrared Space Observatory Polarimetric Imaging of the Egg Nebula (RAFGL 2688)

We present polarimetric imaging of the protoplanetary nebula RAFGL 2688 obtained at 4.5 microns with the Infrared Space Observatory (ISO). We have deconvolved the images to remove the signature of the point spread function of the ISO telescope, to the extent possible. The deconvolved 4.5 micron image and polarimetric map reveal a bright point source with faint, surrounding reflection nebulosity. The reflection nebula is brightest to the north-northeast, in agreement with previous ground- and space-based infrared imaging. Comparison with previous near-infrared polarimetric imaging suggests that the polarization of starlight induced by the dust grains in RAFGL 2688 is more or less independent of wavelength between 2 microns and 4.5 microns. This, in turn, indicates that scattering dominates over thermal emission at wavelengths as long as ~5 microns, and that the dust grains have characteristic radii < 1 micron.Comment: 27 pages, 9 figures; to appear in the Astronomical Journal, May 2002 issu

Pink noise in rowing ergometer performance and the role of skill level

The aim of this study was to examine (1) the temporal structures of variation in rowers' (natural) ergometer strokes in order to make inferences about the underlying motor organization, and (2) the relation between these temporal structures and skill level. Four high-skilled and five lower-skilled rowers completed 550 strokes on a rowing ergometer. Detrended Fluctuation Analysis was used to quantify the temporal structure of the intervals between force peaks. Results showed that the temporal structure differed from random, and revealed prominent patterns of pink noise for each rower. Furthermore, the high-skilled rowers demonstrated more pink noise than the lower-skilled rowers. The presence of pink noise suggests that rowing performance emerges from the coordination among interacting component processes across multiple time scales. The difference in noise pattern between high-skilled and lower-skilled athletes indicates that the complexity of athletes' motor organization is a potential key characteristic of elite performance

Unravelling the many facets of human cooperation in an experimental study

Humans readily cooperate, even with strangers and without prospects of reciprocation. Despite thousands of studies, this finding is not well understood. Most studies focussed on a single aspect of cooperation and were conducted under anonymous conditions. However, cooperation is a multi-faceted phenomenon, involving generosity, readiness to share, fairness, trust, trustworthiness, and willingness to take cooperative risks. Here, we report findings of an experiment where subjects had to make decisions in ten situations representing different aspects of cooperation, both under anonymous and ‘personalised’ conditions. In an anonymous setting, we found considerable individual variation in each decision situation, while individuals were consistent both within and across situations. Prosocial tendencies such as generosity, trust, and trustworthiness were positively correlated, constituting a ‘cooperativeness syndrome’, but the tendency to punish non-cooperative individuals is not part of this syndrome. In a personalised setting, information on the appearance of the interaction partner systematically affected cooperation-related behaviour. Subjects were more cooperative toward interaction partners whose facial photographs were judged ‘generous’, ‘trustworthy’, ‘not greedy’, ‘happy’, ‘attractive’, and ‘not angry’ by a separate panel. However, individuals eliciting more cooperation were not more cooperative themselves in our experiment. Our study shows that a multi-faceted approach can reveal general behavioural tendencies underlying cooperation, but it also uncovers new puzzling features of human cooperation