Postural control in quiet standing is often explained by a reflexive response to optical flow, the apparent motion of environmental objects in a visual scene. However, moving room experiments show ...that even small-amplitude body sway can evoke odd sensations or motion sickness, indicating that a consciousness factor may also be involved. Studies targeting perception of self-motion, vection, typically use rapid visual stimuli moving in a single direction to maintain a constant feeling of vection, and there are few studies of vection using low-speed sinusoidal visual stimuli similar to human pendular movement. In the present study we searched for changes in postural control during periods of vection during quiet standing. Participants (N = 19, age = 20.4 ±1.1 years) were shown dynamic visual stimuli in the form of sinusoidally expanding and contracting random dots, and the stimuli speed and visual field were manipulated. Posture was continually evaluated using Center of Pressure (CoP) measurements. Participants were also asked to report feelings of vection, both by pressing a button during the trial and through an overall rating at the end of each trial. Using repeated-measures ANOVA, we assessed changes in the CoP and vection variables between experimental conditions, as well as possible interactions between the variables. The results show that postural reaction and vection were both affected by the visual stimuli and varied with speed. The peripheral visual field was found to couple to stronger feeling of vection and better quality of postural control. However, no significant relationship between postural control and vection, nor evidence of vection interaction to the relationship between optical flow and postural control, was found. Based on our results we conclude that for postural stability during quiet standing, visual cues dominate over any potential consciousness factor arising due to vection.
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•The executive function of the unconscious working memory was investigated.•Participants were asked to compare two masked visual stimuli under the delayed match-to-sample task.•The rate of correct ...responses to given two unconscious visual items was above chance level.•The executive function could be driven by unconscious visual inputs.
Recent studies argued that unconscious visual information could access the working memory, however, it is still unclear whether the central executive could be activated unconsciously. We investigated, using a delayed match-to-sample task, whether the central executive is an unconscious process. In the experiment of the present study, participants were asked to compare the locations of two given visual targets. Both targets (or one of the two targets, depending on the experimental condition) were masked by a visual masking paradigm. The results showed an above-chance-level performance even in the condition that participants compared two unconscious targets. However, when the trials with the non-visual conscious experience of the target were removed from the analysis, the performance was no longer significantly different from chance level. Our results suggest that the central executive could be activated unconsciously by some level of stimulus signal, that is still below the threshold for a subjective report.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
It has long been thought that vision is the most essential factor in maintaining stable quiet standing compared to other sources (i.e., vestibular and somatosensory inputs) of information. ...Specifically, several vision studies on postural control have shown evidence for the importance of the visual system, particularly peripheral vision rather than central vision, and optical flow. Nevertheless, to date, no study has manipulated both visual field and optical flow concurrently. In the present study, we experimentally manipulated both the visual field (the central and peripheral visual fields) and the occurrence of optical flow during quiet standing, examining the effects of the visual field and optical flow on postural sway measured in terms of the center of pressure (CoP). Stationary random dot stimuli were presented exclusively in either the central or peripheral visual field, while the occurrence of optical flow was manipulated using a desktop (DTD) or a head-mounted (HMD) display. The optical flow that occurred while using the DTD was a function of the postural sway during quiet standing, while for the HMD, no optical flow occurred even when the body/head swayed during quiet standing. Our results show that the extent of postural sway (e.g., CoP area) was smaller when visual stimuli were presented in the peripheral visual field than that in the central visual field; this was the case while using the DTD alone, with no effects of the peripheral vision on the extent of postural sway while using the HMD. It is therefore suggested that the optical flow occurring in the peripheral visual field is essential for stable quiet standing.
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Simulating climbing movements on a given route is important for fluent rock climbing. We investigated the effect of simulated action during rock climbing route finding on memory and exploratory ...movement. Participants were 12 climbers and 12 non-climbers who completed three experimental tasks: (a) a questionnaire, the Vividness of Movement Imagery Questionnaire-2 (VMIQ-2) for measuring vividness of motor imagery, (b) a memory task requiring recognition of rock climbing holds on the route, and (c) a traversing task requiring participants to climb a given route and count the number of exploratory movements made during climbing. During route finding in the memory/traversing task, we experimentally manipulated the simulative body action with motor imagery. Results showed that the simulative action affected exploratory movement during climbing, but it did not affect memorization of the holds. In the traversing task, climbers showed more exploratory movement when the simulative action was present during route finding, while the non-climbers showed an opposite trend. Moreover, for non-climbers, the effect of the simulative action was modulated by the vividness of kinesthetic imagery. We concluded that simulative body action during route finding facilitated motor imagery and spatial information processing for subsequent climbing involving exploratory movement.
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The current study investigated whether children’s mental representations of numbers are organized spatially at the onset of formal schooling using a manual-pointing task. First-graders (
N
= 77) saw ...four numbers (1, 3, 7, 9) presented randomly in four spatial positions (extreme left, left, right, extreme right) on a touch screen. In a Go/No-Go task, children were asked to press the appearing numbers as fast and accurately as possible, but only when the numbers were “smaller” (or “larger” in a different block) than 5. Results indicated that response times were significantly affected by the spatial position in which the different numbers were presented. Response times for small numbers (1 and 3) increased and response times for large numbers (7 and 9) decreased, the more they were presented towards the right side of the screen. These findings suggested that first-graders spontaneously employed a spatial number representation that was oriented from left to right. Furthermore, this left-to-right organization could not be easily changed by priming a different direction. Our findings indicate that even young children map numbers continuously onto space.
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CEKLJ, DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
How do athletes represent actions from their sport? How are these representations structured and which knowledge is shared among experts in the same discipline? To address these questions, the event ...segmentation task was used. Experts in Taekwondo and novices indicated how they would subjectively split videos of Taekwondo form sequences into meaningful units. In previous research, this procedure was shown to unveil the structure of internal action representations and to be affected by sensorimotor knowledge. Without specific instructions on the grain size of segmentation, experts tended to integrate over longer episodes which resulted in a lower number of single units. Moreover, in accordance with studies in figure-skating and basketball, we expected higher agreement among experts on where to place segmentation marks, i.e., boundaries. In line with this hypothesis, significantly more overlap of boundaries was found within the expert group as compared to the control group. This was observed even though the interindividual differences in the selected grain size were huge and expertise had no systematic influence here. The absence of obvious goals or objects to structure Taekwondo forms underlines the importance of shared expert knowledge. Further, experts might have benefited from sensorimotor skills which allowed to simulate the observed actions more precisely. Both aspects may explain stronger agreement among experts even in unfamiliar Taekwondo forms. These interpretations are descriptively supported by the participants’ statements about features which guided segmentation and by an overlap of the group’s agreed boundaries with those of an experienced referee. The study shows that action segmentation can be used to provide insights into structure and content of action representations specific to experts. The mechanisms underlying shared knowledge among Taekwondoists and among experts in general are discussed on the background of current theoretic frameworks.
The purpose of this study was to examine and compare Mongolians (118 men and 252 women) and Japanese (158 men and 201 women) university students’ awareness related to their occupation and their ...motivations for entering university. The survey focused on the vocational motives, university performance/experiences, and motivations for entering university. The analyses showed that although Mongolian and Japanese students have similar occupational views, there are some cultural differences that can be mainly identified with the recent historic developments and social changes both the nations experienced (e.g socialistic era in Mongolia).
Representational momentum (RM) is the phenomenon that occurs when an object moves and then disappears, and the recalled final position of the object shifts in the direction of its motion. Some ...previous findings indicate that the magnitude of RM in early childhood is comparable to that in adulthood, whereas other findings suggest that the magnitude of RM is significantly greater in childhood than in adulthood. We examined whether the inconsistencies between previous studies could be explained by differences in the experimental tasks used in these studies. Futterweit and Beilin used a same-different judgment between the position where a moving stimulus disappeared and where a comparison stimulus reappeared (judging task), whereas Hubbard et al. used a task wherein a computer mouse cursor pointed to the position where the moving stimulus disappeared (pointing task). Three age groups (M = 7.4, 10.7, and 22.1 years, respectively) participated in both the judging and pointing tasks in the current study. A multivariate analysis of variance with the magnitudes of RM in each task as dependent variables revealed a significant main effect for age. A one-way analysis of variance performed for each of the judging and pointing tasks also indicated a significant main effect of age. However, post hoc multiple comparisons detected a significant age effect only for the pointing task. The inconsistency between the judging and pointing tasks was discussed related to the distinct effect size of the age difference in the magnitude of RM between the two tasks.
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We investigated the effects of pursuit effort against the optokinetic nystagmus (OKN) on induced motion (IM) by measuring vertical IM and eye movements. Participants viewed an inducing stimulus (a ...random dot pattern) moving either upward or downward at the velocity of 10 or 40 °/s. A horizontally moving target (a single dot) was then presented within the inducing stimulus. Participants were asked to pursue the target and report the perceived slant of the target motion path by using a joystick. The results showed that IM magnitude was larger with an upward stimulation than with a downward stimulation. IM magnitude was also larger at 40 °/s than at 10 °/s. The results of eye movements prior to the target presentation showed that OKN was elicited more effectively with an upward stimulation than with a downward stimulation and at 40 °/s than at 10 °/s. OKN was markedly reduced when the target was presented within the inducing stimulus. These results support the oculomotor theory that IM magnitude reflects pursuit effort against OKN in response to an inducing stimulus.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, ODKLJ, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
We learn counting on our fingers, and the digital representation of numbers we develop is still present in adulthood Andres M, et al. (2007) J Cognit Neurosci 19:563-576. Such an anatomy-magnitude ...association establishes tight functional correspondences between fingers and numbers Di Luca S, et al. (2006) Q J Exp Psychol 59:1648-1663. However, it has long been known that small-to-large magnitude information is arranged left-to-right along a mental number line Dehaene S, et al. (1993) J Exp Psychol Genet 122:371-396. Here, we investigated touch perception to disambiguate whether number representation is embodied on the hand ("1" = thumb; "5" = little finger) or disembodied in the extrapersonal space ("1" = left; "5" = right). We directly contrasted these number representations in two experiments using a single centrally located effector (the foot) and a simple postural manipulation of the hand (palm-up vs. palm-down). We show that visual presentation of a number ("1" or "5") shifts attention cross-modally, modulating the detection of tactile stimuli delivered on the little finger or thumb. With the hand resting palm-down, subjects perform better when reporting tactile stimuli delivered to the little finger after presentation of number "5" than number "1." Crucially, this pattern reverses (better performance after number "1" than "5") when the hand is in a palm-up posture, in which the position of the fingers in external space, but not their relative anatomical position, is reversed. The human brain can thus use either space- or body-based representation of numbers, but in case of competition, the former dominates the latter, showing the stronger role played by the mental number line organization.
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