Crossing the arms confuses the clocks: Sensory feedback and the bimanual advantage

The bimanual advantage refers to the finding that tapping with two fingers on opposite hands exhibits reduced timing variability, as compared with tapping with only one finger. Two leading theories propose that the bimanual advantage results from the addition of either sensory (i.e., enhanced feedback) or cognitive (i.e., multiple timekeeper) processes involved in timing. Given that crossing the arms impairs perception of tactile stimuli and modulates cortical activation following tactile stimulation, we investigated the role of crossing the arms in the bimanual advantage. Participants tapped unimanually or bimanually with their arms crossed or uncrossed on a tabletop or in the air. With arms crossed, we expected increased interval timing variance. Similarly, for air tapping, we expected reduced bimanual advantage, due to reduced sensory feedback. A significant bimanual advantage was observed for the uncrossed, but not the crossed posture in tabletop tapping. Furthermore, removing tactile feedback from taps eliminated the bimanual advantage for both postures. Together, these findings suggest that crossing the arms likely impairs integration of internal (i.e., effector-specific) and external (i.e., environment-specific) information and that this multisensory integration is crucial to reducing timing variability during repetitive coordinated bimanual tasks.     

Dynamic deformation of shape-memory alloys: Evidence of domino detwinning?

Deformation of NiTi shape-memory alloys (SMAs) under dynamic tension has been studied. It is found that the stress plateau associated with detwinning still exists at the highest strain rate tested (300s -1 ). Beyond the stress plateau, when dislocation mechanisms dominate the deformation process, the strain-hardening effect is more strongly dependent on strain rate. The dynamically deformed specimens exhibit a shape-recovery process and a two-way memory effect which are identical with that for the alloy deformed under quasistatic conditions. The observations suggest that the detwinning process takes place in SMAs under dynamic tension.     

The role of shape recognition in figure/ground perception in infancy

In this study we sought to determine whether infants, like adults, utilize previous experience to guide figure/ground processing. After familiarization to a shape, 5-month-olds preferentially attended to the side of an ambiguous figure/ground test stimulus corresponding to that shape, suggesting that they were viewing that portion as the figure. Infants’ failure to exhibit this preference in a control condition in which both sides of the test stimulus were displayed as figures indicated that the results in the experimental condition were not due to a preference between two figure shapes. These findings demonstrate for the first time that figure/ground processing in infancy is sensitive to top-down influence. Thus, a critical aspect of figure/ground processing is functional early in life.     

From the Desk of Editor-in-Chief

Journal of Indian Council of Philosophical Research -     

Young infants readily use proximity to organize visual pattern information

Four experiments relying on novelty and spontaneous preference procedures were performed to determine whether 3-4-month-old infants utilize the Gestalt principle of proximity to organize visual pattern information. In Experiment 1, infants familiarized with arrays of elements that could be organized into either columns or rows were tested for their preference between vertical and horizontal bars. The infants preferred the novel organization of bars. Experiments 2 and 3 showed that the novelty preference could not be attributed to an a priori preference or an inability to discriminate between the elements comprising the patterns. Experiment 4 replicated the results of Experiment 1 in a bars --> elements version of the task, indicating that extended exposure is not necessary for infants to organize based on proximity. The results suggest that infants readily organize visual pattern information in accord with proximity. Implications of this finding for models of the ontogenesis and microgenesis of object perception in infants and adults are discussed.     

Piagetian Studies of Cognitive Development in India

The paper presents a review of studies on cognitive development of children in India inspired by Piaget’s theory of cognitive development. Piaget’s theory is briefly introduced before examining its cross-cultural applications. Early studies of cognitive development, which focus on age-related changes in cognition, are described. These are followed by the studies of the last decades in which developmental contexts, such as those provided by ecology, culture, schooling, and various forms of training, are implicated. Studies of spatial cognition are discussed in some detail and points of convergence between findings of Indian studies and those reported by Piaget are critically examined. The issue of “performance” vs. “competence” is addressed and research evidence that considers performance difference as a matter of cognitive style is presented. Possible reasons for decline of research interest in Piagetian studies in recent years is examined and suggestion for future studies in this field are offered.     

Characterization of the aggregated phase in KCl:Cd2+ and KCl:Mn2+ by Raman spectroscopy

Abstract

The aggregated phase of the impurities in the systems KCl:Cd²⁺ and KCl:Mn²⁺ has been identified as the Suzuki phase by Raman spectroscopy. The linear increase in the integrated scattering intensities of the Raman lines with concentration of the impurities may be attributed to an increase in the mean precipitate size of the Suzuki phase.     

Development of Spatial Language and Cognition in Hindi- and Sanskrit-Medium Schools

This paper describes a study carried out at Varanasi on the development of geocentric spatial cognition with 4–14 year old children of Hindi and Sanskrit medium schools. A number of tasks and procedures were used to assess the spatial frames of reference children used in describing and interpreting spatial displays. Analysis revealed that Sanskrit medium school children used more geocentric language and encoding than Hindi medium school children. The effect of age was significant only for encoding, not for language. Geocentric spatial cognition was significantly linked to fundamental spatial cognitive ability, as measured by Story-Pictorial Embedded Figures Test and Block Designs Test. The stronger expression of geocentric language and geocentric encoding in Sanskrit than Hindi medium school children suggests that the use of the ability can be sharpened by its practice and actualization in day-to-day life. The relationship between language and encoding was found to be of a moderate level suggesting that geocentric cognition is not determined by language alone, but also by other factors present in children’s eco-cultural contexts.