Can low-cost motion-tracking systems substitute a Polhemus system when researching social motor coordination in children?

Functionally stable and robust interpersonal motor coordination has been found to play an integral role in the effectiveness of social interactions. However, the motion-tracking equipment required to record and objectively measure the dynamic limb and body movements during social interaction has been very costly, cumbersome, and impractical within a non-clinical or non-laboratory setting. Here we examined whether three low-cost motion-tracking options (Microsoft Kinect skeletal tracking of either one limb or whole body and a video-based pixel change method) can be employed to investigate social motor coordination. Of particular interest was the degree to which these low-cost methods of motion tracking could be used to capture and index the coordination dynamics that occurred between a child and an experimenter for three simple social motor coordination tasks in comparison to a more expensive, laboratory-grade motion-tracking system (i.e., a Polhemus Latus system). Overall, the results demonstrated that these low-cost systems cannot substitute the Polhemus system in some tasks. However, the lower-cost Microsoft Kinect skeletal tracking and video pixel change methods were successfully able to index differences in social motor coordination in tasks that involved larger-scale, naturalistic whole body movements, which can be cumbersome and expensive to record with a Polhemus. However, we found the Kinect to be particularly vulnerable to occlusion and the pixel change method to movements that cross the video frame midline. Therefore, particular care needs to be taken in choosing the motion-tracking system that is best suited for the particular research.     

Age-Related Changes in Smoothness of Gait of Healthy Children and Early Adolescents

Abstract

In this study, we acquired and processed trunk accelerations during level walking in 85 children aged 8-13?years to calculate spatio-temporal parameters and Harmonic Ratio (HR), which is a metrics representative of gait smoothness and step-to-step symmetry. The results show that while spatio-temporal parameters remain unchanged once normalized considering individuals’ anthropometry, significantly higher values of HR for both the antero-posterior and vertical directions were found in participants aged 12–13 with respect to those of 8–9. This indicates an improvement of gait symmetry, which suggests that the gait maturation process is still ongoing for the age ranges tested here.     

Context-dependent memory for meaningful material: information for students

Context-dependency effects on memory for lists of unrelated words have been shown more often with recall than with recognition. Context dependency for meaningful text material was examined using two standard academic testing techniques: short answer (recall) and multiple choice (recognition). Forty participants read an article in either silent or noisy conditions; their reading comprehension was assessed with both types of test under silent or noisy conditions. Both tests showed context-dependency effects in which performance was better in the matching conditions (silent study/silent test and noisy study/noisy test) than in the mismatching conditions (silent study/noisy test and noisy study/silent test). Context cues appear to be important in the retrieval of newly learned meaningful information. An academic application is that students may perform better on exams by studying in silence. Copyright © 1998 John Wiley & Sons, Ltd.     

Children's reading of words, pseudohomophones, and other nonwords

In Experiment 1 children aged 8-9 and 9-10 years were tested for neighbourhood and pseudohomophone effects in nonword reading. Neighbourhood effects ( N effects) were robust irrespective of group or type of nonword. Pseudohomophones were read more accurately than other nonwords but this finding was robust only for the younger 8-9-year-olds. High-frequency words were read more accurately than low-frequency words, but the reverse applied to pseudohomophones based on high- and low-frequency words, although this was not robust. Error rates for the 9-10-year-olds in Experiment 1 were low, and so it was difficult to interpret the lack of a pseudohomophone advantage for reading nonwords in this age group. Experiment 2 was therefore carried out, which consisted of a replication of the first study with a further group of 9- 10-year-olds, but pronunciation latencies were measured, as well as accuracy. All the effects obtained in Experiment 1 were replicated but, in addition, an advantage for pseudohomophones in terms of pronunciation latencies was observed. The implications for accounts of reading development are discussed.     

Do Abrupt-onset Peripheral Cues Attract Attention Automatically?

The proportion of peripheral cues that predicted at which of two locations a discrimination target would occur was manipulated in three experiments. Near cues occurred adjacent to the target and far cues occurred adjacent to the other location. In Experiment 1, near and far cues were presented in separate blocks so each predicted target location. Both types of cue produced benefit relative to a neutral baseline. In Experiment 2 expectancy for near versus far cues was manipulated. In one group, 80% of the peripheral cues were near; in another, only 20% were near; in a third, near and far cues occurred randomly. Near cues always produced benefit. Far cues produced benefit when they were expected, had no effect in the random group, and sometimes produced cost when they were unexpected. Experiment 3 repeated the near-expected and far-expected conditions, but target duration was shortened to 50 msec. A similar pattern emerged, except that near cues produced less benefit at longer SOAs when they were unexpected. The data suggest that peripheral, abrupt-onset cues may produce benefit via an automatic process, but that such a process is more like location priming than the capture of attention. Expectancy determines whether and where attentional resources will be allocated in response to the cue.     

2D or not 2D? An fMRI study of how dogs visually process objects

Animal Cognition - Given humans’ habitual use of screens, they rarely consider potential differences when viewing two-dimensional (2D) stimuli and real-world versions of dimensional stimuli....