Blind footballers direct their head towards an approaching ball during ball trapping

In blind football, players predict the sound location of a ball to underpin the success of ball trapping. It is currently unknown whether blind footballers use head movements as a strategy for trapping a moving ball. This study investigated characteristics of head rotations in blind footballers during ball trapping compared to sighted nonathletes. Participants performed trapping an approaching ball using their right foot. Head and trunk rotation angles in the sagittal plane, and head rotation angles in the horizontal plane were measured during ball trapping. The blind footballers showed a larger downward head rotation angle, as well as higher performance at the time of ball trapping than did the sighted nonathletes. However, no significant differences between the groups were found with regards to the horizontal head rotation angle and the downward trunk rotation angle. The blind footballers consistently showed a larger relative angle of downward head rotation from an early time point after ball launching to the moment of ball trapping. These results suggest that blind footballers couple downward head rotation with the movement of an approaching ball, to ensure that the ball is kept in a consistent egocentric direction relative to the head throughout ball trapping.

Speech behaviour of Latvian Russian-speaking schoolchildren in argumentative texts

The article analyses the problems, which Russian-speaking schoolchildren in Latvia meet while creating written argumentative texts. The topicality of the article lies in the peculiarities of forming the schoolchildren’s linguistic personality in the diaspore during bilingual education. The author focuses on the main problems in the schoolchildren’s written speech and their reasons. The criteria of text content-analysis were as follows: 1) the level of argumentation autonomy; 2) the quality of the arguments; 3) the level of argument unfoldedness and using different types of arguments; 4) speech expressiveness and observing language norms. The ninth-graders’ text analysis led the author to the following conclusions: the compositions of most schoolchildren partly correspond with argumentative texts (in the aspect of their contents, structure, quantity and quality of arguments, means of thought development); they lack intertextual embeddings (the texts are “poor” in the sense aspect); in the speech behaviour there dominates an explicit I-communication (reflexive observations, egocentric direction of their behaviour), pragmatic, naked outline of facts even if the topic of the text motivates to verbalize emotions; there are a lot of language errors. The results of the research are based on analysis of 3296 ninth-graders, which the schoolchildren wrote at Russian language exam on finishing secondary school in 2016-2018. The results of this and further researches will allow the author to deeply investigate the process of forming primary and secondary linguistic personality of a Russian-speaking schoolchild in Latvia.

Allocentric location cues and the visual guidance of walking towards seen targets

We hypothesised allocentric location cues (information about the location of an observer relative to the surrounding environment) have a role in the on-line visual guidance of walking towards seen target objects. We used a standard technique for assessing the contribution of cues when walking to targets: we perturbed the perceived egocentric direction of the target, and measured the curvature of the resultant walking trajectories. By removing motion cues we were able to isolate allocentric location cues and quantify their utility. Enclosed, geometrically regular, environments contain rich allocentric location cues. In the first experiment participants walked through a large enclosed outdoor space; allocentric cues were isolated by synchronised eye closing and stepping. In the second experiment participants walked through a smaller enclosed indoor space; allocentric cues were isolated with stroboscopic lighting. Both experiments provided support for the hypothesis that, when they are available, allocentric location cues have a key role when walking to seen targets.

Peripersonal versus extrapersonal visual scene information for egocentric direction and position perception

When perceiving the visual environment, people simultaneously perceive their own direction and position in the environment (i.e., egocentric spatial perception). This study investigated what visual information in a scene is necessary for egocentric spatial perceptions. In two perception tasks (the egocentric direction and position perception tasks), observers viewed two static road images presented sequentially. In Experiment 1, the critical manipulation involved an occluded region in the road image, an extrapersonal region (far-occlusion) and a peripersonal region (near-occlusion). Egocentric direction perception was worse in the far-occlusion condition than in the no-occlusion condition, and egocentric position perceptions were worse in the far- and near-occlusion conditions than in the no-occlusion condition. In Experiment 2, we conducted the same tasks manipulating the observers’ gaze location in a scene—an extrapersonal region (far-gaze), a peripersonal region (near-gaze) and the intermediate region between the former two (middle-gaze). Egocentric direction perception performance was the best in the far-gaze condition, and egocentric position perception performances were not different among gaze location conditions. These results suggest that egocentric direction perception is based on fine visual information about the extrapersonal region in a road landscape, and egocentric position perception is based on information about the entire visual scene.

Cyclopean vs. Dominant Eye in Gaze-Interface-Tracking

User-centered design questions in gaze interfaces have been explored in multitude empirical investigations. Interestingly, the question of what eye should be the input device has never been studied. We compared tracking accuracy between the “cyclopean” (i.e., midpoint between eyes) dominant and non-dominant eye. In two experiments, participants performed tracking tasks. In Experiment 1, participants did not use a crosshair. Results showed that mean distance from target was smaller with cyclopean than with dominant or non-dominant eyes. In Experiment 2 participants controlled a crosshair with their cyclopean, dominant and non-dominant eye intermittently and had to align the crosshair with the target. Overall tracking accuracy was highest with cyclopean eye, yet similar between cyclopean and dominant eye in the second half of the experiment. From a theoretical viewpoint, our findings correspond with the cyclopean eye theory of egocentric direction and lend support to the hemispheric laterality approach of eye dominance. From a practical viewpoint, we show that what eye to use as input should be a design consideration in gaze interfaces.

Influence of optic flow on the control of heading and target egocentric direction during steering toward a goal

Although previous studies have shown that people use both optic flow and target egocentric direction to walk or steer toward a goal, it remains in question how enriching the optic flow field affects the control of heading specified by optic flow and the control of target egocentric direction during goal-oriented locomotion. In the current study, we used a control-theoretic approach to separate the control response specific to these two cues in the visual control of steering toward a goal. The results showed that the addition of optic flow information (such as foreground motion and global flow) in the display improved the overall control precision, the amplitude, and the response delay of the control of heading. The amplitude and the response delay of the control of target egocentric direction were, however, not affected. The improvement in the control of heading with enriched optic flow displays was mirrored by an increase in the accuracy of heading perception. The findings provide direct support for the claim that people use the heading specified by optic flow as well as target egocentric direction to walk or steer toward a goal and suggest that the visual system does not internally weigh these two cues for goal-oriented locomotion control.