Validity and reliability of a radio positioning system for tracking athletes in indoor and outdoor team sports

Radio-frequency local positioning systems (LPS) have the potential to provide accurate location information about sport players for performance analysis, making available for study the emergent nature of interpersonal coordination and collective decision-making behaviour among players in both indoor and outdoor sports. However, no available publications have validated the performance of LPS for indoor sports. The objective of this study was to validate the performance of an LPS in an indoor venue and to compare it to performance observed in an outdoor venue using static and dynamic measurements. Our results showed that the absolute positioning errors obtained from the static measurements of the LPS were comparable for both indoor and outdoor venues, with mean errors of 12.1?cm outdoors and 11.9?cm indoors. From the dynamic measurements, we analysed the relative position error and the distance estimation performance of the system. The 90th-percentile relative position errors were 28?cm for the indoor venue versus 18?cm for the outdoor venue. On average, the LPS overestimated the distance travelled, and the performance was similar for both indoor and outdoor venues. On a linear course, the mean errors of the distance estimates were 2.2% of the total distance indoors and 1.3% outdoors, and on a nonlinear course, they were 2.7% indoors and 3.2% outdoors.     

Diversifying experiences enhance cognitive flexibility

Past research has linked creativity to unusual and unexpected experiences, such as early parental loss or living abroad. However, few studies have investigated the underlying cognitive processes. We propose that these experiences have in common a “diversifying” aspect and an active involvement, which together enhance cognitive flexibility (i.e., creative cognitive processing). In the first experiment, participants experienced complex unusual and unexpected events happening in a virtual reality. In the second experiment, participants were confronted with schema-violations. In both experiments, comparisons with various control groups showed that a diversifying experience – defined as the active (but not vicarious) involvement in an unusual event – increased cognitive flexibility more than active (or vicarious) involvement in normal experiences. Our findings bridge several lines of research and shed light on a basic cognitive mechanism responsible for creativity.     

A dual identity-electronic contact (DIEC) experiment promoting short- and long-term intergroup harmony

Existing intergroup harmony programs have been short in length with little long-term evaluation of their true effectiveness. This experiment addresses this limitation through the development and evaluation of a new intergroup harmony program that integrates dual identity and contact tenets. At Time 1, 116 Australian Muslim and 104 Australian Christian first-year high school students attending religiously segregated schools completed pre-test measures of intergroup bias, intergroup anxiety, prejudice, and outgroup knowledge. Eight months later, in the next year of school, these students were allocated to either the nine-week dual identity-electronic or E-contact (DIEC) program that involved Muslim and Christians interacting via a synchronous internet chat tool, or the control condition where they completed the program within their religious groups with no recategorization. All participants completed the same pre-test measures at two weeks (Time 2) and 6-months (Time 3) post-program. At Time 2, for students in the DIEC condition, intergroup bias and intergroup anxiety decreased significantly, and outgroup knowledge increased significantly, compared to the control condition. In the case of intergroup bias, the decrease was maintained at Time 3. Moderation effects of ingroup identification and outgroup friendship, and mediation effects of intergroup anxiety were also found. These encouraging findings highlight that carefully designed E-contact programs can successfully promote intergroup harmony in both the short- and long-term.     

Relationship between loudness tolerance and the acceptance of background noise for young adults with normal hearing

This study investigated the relationship between listener loudness tolerance and listener acceptable noise level (ANL). Twenty-five normal hearing adults completed loudness tolerance and acceptable noise level measures. Loudness tolerance was measured using a scaling technique. The acceptable noise levels were calculated from a procedure designed to quantify a listener's willingness to accept background noise while listening to speech. Pearson correlation confirmed that loudness tolerance and acceptable noise levels are not related.     

The experience of force: the role of haptic experience of forces in visual perception of object motion and interactions, mental simulation, and motion-related judgments

Forces are experienced in actions on objects. The mechanoreceptor system is stimulated by proximal forces in interactions with objects, and experiences of force occur in a context of information yielded by other sensory modalities, principally vision. These experiences are registered and stored as episodic traces in the brain. These stored representations are involved in generating visual impressions of forces and causality in object motion and interactions. Kinematic information provided by vision is matched to kinematic features of stored representations, and the information about forces and causality in those representations then forms part of the perceptual interpretation. I apply this account to the perception of interactions between objects and to motions of objects that do not have perceived external causes, in which motion tends to be perceptually interpreted as biological or internally caused. I also apply it to internal simulations of events involving mental imagery, such as mental rotation, trajectory extrapolation and judgment, visual memory for the location of moving objects, and the learning of perceptual judgments and motor skills. Simulations support more accurate judgments when they represent the underlying dynamics of the event simulated. Mechanoreception gives us whatever limited ability we have to perceive interactions and object motions in terms of forces and resistances; it supports our practical interventions on objects by enabling us to generate simulations that are guided by inferences about forces and resistances, and it helps us learn novel, visually based judgments about object behavior.     

Saccade launch site as a predictor of fixation durations in reading: comments on Hand, Miellet, O'Donnell, and Sereno (2010)

An important question in research on eye movements in reading is whether word frequency and word predictability have additive or interactive effects on fixation durations. A fair number of studies have reported only additive effects of the frequency and predictability of a target word on reading times on that word, failing to show significant interactions. Recently, however, Hand, Miellet, O'Donnell, and Sereno (see record 2010-19099-001) reported interactive effects in a study that included the distance of the prior fixation from the target word (launch site). They reported that when the saccade into the target word was launched from very near to the word (within 3 characters), the predictability effect was larger for low frequency words, but when the saccade was launched from a medium distance (4-6 characters from the word) the predictability effect was larger for high frequency words. Hand et al. argued for the importance of including launch site in analyses of target word fixation durations. Here we describe several problems with Hand et al.'s use of analyses of variance in which launch site is divided into distinct ordinal levels. We describe a more appropriate way to analyze such data-linear mixed-effect models-and we use this method to show that launch site does not modulate the interaction between frequency and predictability in two other data sets.     

The distribution of fixation durations during reading: effects of stimulus quality

Participants' eye movements were recorded as they read single sentences presented normally, presented entirely in faint text, or presented normally except for a single faint word. Fixations were longer when the entire sentence was faint than when the sentence was presented normally. In addition, fixations were much longer on a single faint word embedded in normal text, compared to when the entire sentence was faint. The primary aim of the study was to examine the influence of stimulus quality on the distribution of fixation durations. Ex-Gaussian fitting revealed that stimulus quality affected the mean of the Normal component, but in contrast to results from single-word tasks (Plourde & Besner, 1997), stimulus quality did not affect the exponential component, regardless of whether one or all words were faint. The results also contrast with the finding (Staub, White, Drieghe, Hollway, & Rayner, 2010) that the word frequency effect on fixation durations is an effect on both of the critical distributional parameters. These findings are argued to have implications for the interpretation of the role of stimulus quality in word recognition, and for models of eye movement control in reading.     

The influence of attention on learning and performance: pre-movement time and accuracy in an isometric force production task

Lohse, Sherwood, and Healy (2010) found that an external focus of attention (FOA) improved performance in a dart-throwing task and reduced the time taken between throws, but using the time between trials as a measure of preparation time is relatively crude. Thus, the current experiment analyzed how FOA affects accuracy and pre-movement time in an isometric force production task, to study how FOA affected motor planning. In the current experiment, training with an external focus improved the accuracy of the isometric force production task during training and during retention and transfer testing. During training, an external FOA also significantly reduced pre-movement time in early trials. These findings are interpreted as reduced explicit control of movement as a function of an external FOA, and help to integrate FOA research with other motor control phenomena and neuropsychological theories of motor control.     

Neural activation underlying cognitive control in the context of neutral and affectively charged pictures in children

The neural correlates of cognitive control for typically developing 9-year-old children were examined using dense-array ERPs and estimates of cortical activation (LORETA) during a go/no-go task with two conditions: a neutral picture condition and an affectively charged picture condition. Activation was estimated for the entire cortex after which data were exported for four regions of interests (ROIs): ventrolateral prefrontal cortex (VLPFC), dorsal anterior cingulate cortex (dACC), dorsolateral prefrontal cortex (DLPFC), and orbitofrontal/ventromedial prefrontal cortex (OFC/VMPFC). Results revealed faster reaction times, greater N2 activation, and greater prefrontal activation for the affectively charged picture condition than the neutral picture condition. The findings are discussed in reference to the impact of affective stimuli on recruitment of specific brain regions involved in cognitive control.