Motor coordination uses external spatial coordinates independent of developmental vision

The constraints that guide bimanual movement coordination are informative about the processing principles underlying movement planning in humans. For example, symmetry relative to the body midline benefits finger and hand movements independent of hand posture. This symmetry constraint has been interpreted to indicate that movement coordination is guided by a perceptual code. Although it has been assumed implicitly that the perceptual system at the heart of this constraint is vision, this relationship has not been tested. Here, congenitally blind and sighted participants made symmetrical and non-symmetrical (that is, parallel) bimanual tapping and finger oscillation movements. For both groups, symmetrical movements were executed more correctly than parallel movements, independent of anatomical constraints like finger homology and hand posture. For the blind, the reliance on external spatial factors in movement coordination stands in stark contrast to their use of an anatomical reference frame in perceptual processing. Thus, the externally coded symmetry constraint evident in bimanual coordination can develop in the absence of the visual system, suggesting that the visual system is not critical for the establishment of an external-spatial reference frame in movement coordination.     

Processing load impairs coordinate integration for the localization of touch

To perform an action toward a touch, the tactile spatial representation must be transformed from a skin-based, anatomical reference frame into an external reference frame. Evidence suggests that, after transformation, both anatomical and external coordinates are integrated for the location estimate. The present study investigated whether the calculation and integration of external coordinates are automatic processes. Participants made temporal order judgments (TOJs) of two tactile stimuli, one applied to each hand, in crossed and uncrossed postures. The influence of the external coordinates of touch was indicated by the performance difference between crossed and uncrossed postures, referred to as the crossing effect. To assess automaticity, the TOJ task was combined with a working memory task that varied in difficulty (size of the working memory set) and quality (verbal vs. spatial). In two studies, the crossing effect was consistently reduced under processing load. When the load level was adaptively adjusted to individual performance (Study 2), the crossing effect additionally varied as a function of the difficulty of the secondary task. These modulatory effects of processing load on the crossing effect were independent of the type of working memory. The sensitivity of the crossing effect to processing load suggests that coordinate integration for touch localization is not fully automatic. To reconcile the present results with previous findings, we suggest that the genuine remapping process—that is, the transformation of anatomical into external coordinates—proceeds automatically, whereas their integration in service of a combined location estimate is subject to top-down control.     

Interactions between working memory and language in young children with specific language impairment (SLI)

The underlying structure of working memory (WM) in young children with and without specific language impairment (SLI) was examined. The associations between the components of WM and the language abilities of young children with SLI were then analyzed. The Automated Working Memory Assessment and four linguistic tasks were administered to 58 children with SLI and 58 children without SLI, aged 4–5 years. The WM of the children was best represented by a model with four separate but interacting components of verbal storage, visuospatial storage, verbal central executive (CE), and visuospatial CE. The associations between the four components of WM did not differ significantly for the two groups of children. However, the individual components of WM showed varying associations with the language abilities of the children with SLI. The verbal CE component of WM was moderately to strongly associated with all the language abilities in children with SLI: receptive vocabulary, expressive vocabulary, verbal comprehension, and syntactic development. These results show verbal CE to be involved in a wide range of linguistic skills; the limited ability of young children with SLI to simultaneously store and process verbal information may constrain their acquisition of linguistic skills. Attention should thus be paid to the language problems of children with SLI, but also to the WM impairments that can contribute to their language problems.     

Only correlated sequences that are actively processed contribute to implicit sequence learning

The purpose of the study was to investigate how implicit sequence learning is affected by the presence of secondary information that is correlated with the primary sequence but not necessarily relevant to performance. In a previous work, we have shown that correlation plays an important role but other prerequisites may also be involved. In Experiments 1 and 2, using a task sequence learning paradigm, we found that primary sequence learning was not affected by secondary information that was sequenced but irrelevant to performance, even though the two streams of information were correlated. In contrast, in Experiment 3, we found that sensitivity to the main sequence was greater with the provision of extra sequenced information that was relevant to performance in addition to being correlated. This suggests that sequence learning was enhanced through the integration of information. We conclude that information in secondary as well as primary sequences must be actively processed if it is to have a beneficial impact. By actively processed we mean information that is selectively attended and necessary for carrying out the tasks.     

Early experience of Cued Speech enhances speechreading performance in deaf

It is known that deaf individuals usually outperform normal hearing subjects in speechreading; however, the underlying reasons remain unclear. In the present study, speechreading performance was assessed in normal hearing participants (NH), deaf participants who had been exposed to the Cued Speech (CS) system early and intensively, and deaf participants exposed to oral language without Cued Speech (NCS). Results show a gradation in performance with highest performance in CS, then in NCS, and finally NH participants. Moreover, error analysis suggests that speechreading processing is more accurate in the CS group than in the other groups. Given that early and intensive CS has been shown to promote development of accurate phonological processing, we propose that the higher speechreading results in Cued Speech users are linked to a better capacity in phonological decoding of visual articulators.     

Powered by Imagination: Nanobots at the Science Photo Library

Nanobots have been a key image deployed in nanoscience and nanofiction. At present nanobots are still largely ‘imaginary’. But what do ‘imaginary’ nanobots look like, how are they visually and imaginatively constructed and what functions are they envisioned to have? And what can such images tell us about the aesthetic and cultural conventions and metaphors that are employed, and expectations and visions created or engineered, in the process of ‘visualizing’ nanoscience and nanotechnology for science and society? To answer these questions images of nanobots available at the Science Photo Library were studied. Nanobots were envisioned as ‘working’ mostly in futuristic domains of health and medicine. Most nanobots were artistically rendered as familiar objects or animals, as fulfilling useful functions in healthcare, rather than as running wild and causing harm. Such images were displayed mostly to engage lay publics with biotechnology and nanotechnology. By selectively using metaphors, images of nanobots tended to assimilate the unknown into the known and the unfamiliar into the familiar. This assimilation invites viewers to react to these images as if nanobots already existed and as if they were normal. Thus the images open up a space for ‘normalizing’ this new, rather speculative technology; it is framed in such a way as to invite public acceptance and even excitement.