Nicholas Murray

Event-related potential evidence for the processing efficiency theory

Abstract The purpose of this study was to examine the central tenets of the processing efficiency theory using psychophysiological measures of attention and effort. Twenty-eight participants were divided equally into either a high or low trait anxiety group. They were then required to perform a simulated driving task while responding to one of four target light-emitting diodes. Cortical activity and dual task performance were recorded under two conditions – baseline and competition – with cognitive anxiety being elevated in the competitive session by an instructional set. Although driving speed was similar across sessions, a reduction in P3 amplitude to cue onset in the light detection task occurred for both groups during the competitive session, suggesting a reduction in processing efficiency as participants became more state anxious. Our findings provide more comprehensive and mechanistic evidence for processing efficiency theory, and confirm that increases in cognitive anxiety can result in a reduction of processing efficiency with little change in performance effectiveness.

Acute Physical Activity on Cognitive Function: A Heart Rate Variability Examination

The purpose of this study was to examine the relationship of physical activity and cognitive function (as determined by reaction time and the trail-making test) in active versus non-active participants. Participants were divided into one of four groups: active experimental, active control, non-active experimental and non-active control. All groups completed a complex cognitive task (the trail-making test) as well as a set of reaction time tasks both before and after the experimental session. The experimental groups completed a 30-min exercise session while the control groups monitored the physical activity of the experimental group. In addition to the measures of cognitive function, heart rate variability was recorded during the pre- and post-tests. There was significant cognitive performance improvement in tasks with a higher cognitive and perceptual component. Heart rate variability data indicated that a moderate level of arousal based on sympathetic nervous system activity post exercise was associated with an increase in cognitive performance. The findings are discussed in light of the inverted-U hypothesis.

Implicit overcompensation: The influence of negative self-instructions on performance of a self-paced motor task

Abstract According to Wegners (1994) theory of ironic processes of mental control, self-instructions not to perform in a certain way, together with mental loads, can induce thoughts, emotions, and behaviours that are precisely the opposite of intention. Wegners theory was tested against the implicit overcompensation hypothesis, which states that movement direction and magnitude are implicitly dictated by self-instruction, irrespective of load, promoting overcompensation of action. Two experiments were conducted using a golf-putting task. In Experiment 1, 48 participants were randomly assigned to one of four load conditions: cognitive, visual, auditory, and self-presentation/incentive. In the experimental trials, participants were instructed to make the putt, but it was emphasized that the putt should not be left short of the target. Following the instructional strategy, putts landed significantly longer than at baseline, irrespective of load. In Experiment 2, 36 participants were divided into one of three groups, without load, in which different instructional sets (control, not putting long, and not putting short) were emphasized. A significant interaction emerged, as participants putted significantly longer or shorter than controls depending on the instructional set given. Overall, our findings support the implicit overcompensation hypothesis. Theoretical and practical considerations are discussed.

Effects of strategy use on acquisition of a motor task during various stages of learning.

To specify the optimal point for introducing a learning strategy, 50 participants were randomly assigned into five groups based on the timing of strategy introduction while learning a badminton serve. Groups were instructed in the use of Singers Five-step Strategy either prior to starting their acquisition trials (100% group) or following acquisition Trial Blocks 1 (83% group), 3 (50% group), 5 (17% group) or were assigned to a control (0% group) group). Participants were asked to complete six acquisition trial blocks of 10 serves each, followed by a break and then two retention trial blocks. Scores were obtained by hitting shuttles into a scoring grid, which served as the dependent measure. Data were analyzed using a mixed-model analysis of variance with a group × trial blocks design, which yielded significant main effects for both factors during acquisition. Introduction of a learning strategy may be more efficient once participants have become familiar with the task. No significant differences were observed between groups who received the strategy early and the control group. Thus, it appears that learning strategies should be introduced later in the learning process and may distract if provided too early.

A comparison of visual search strategies of elite and non-elite tennis players through cluster analysis

ABSTRACT Considerable research has documented that successful performance in interceptive tasks (such as return of serve in tennis) is based on the performers’ capability to capture appropriate anticipatory information prior to the flight path of the approaching object. Athletes of higher skill tend to fixate on different locations in the playing environment prior to initiation of a skill than their lesser skilled counterparts. The purpose of this study was to examine visual search behaviour strategies of elite (world ranked) tennis players and non-ranked competitive tennis players (n = 43) utilising cluster analysis. The results of hierarchical (Ward’s method) and nonhierarchical (k means) cluster analyses revealed three different clusters. The clustering method distinguished visual behaviour of high, middle-and low-ranked players. Specifically, high-ranked players demonstrated longer mean fixation duration and lower variation of visual search than middle-and low-ranked players. In conclusion, the results demonstrated that cluster analysis is a useful tool for detecting and analysing the areas of interest for use in experimental analysis of expertise and to distinguish visual search variables among participants’.

Understanding website useability: an eye-tracking study of the Vancouver 2010 Olympic Games website.

E-commerce has become a key element of most sport websites, yet sport websites are expected to do more than sell merchandise. Consequently, sport marketers are faced with a delicate balancing act between ease of use and provision of exciting, multimedia content to meet the needs of their consumers. Eye-tracking technology is used in this study to identify elements that enhance or interfere with website useability. Users were provided with a purchase intention and measures of fixation on relevant areas of interest were collected. Retrospective think alouds provided users a chance to explain their attention patterns. Size, placement, and active links were identified as important features of useability. Experienced online shoppers and women were more likely to focus on the shopping task, and less likely to be distracted by the sport-related features of the site. Implications for using eye-tracking technology for sport marketing are discussed.

The Reliability, Validity, and Normative Data of Interpupillary Distance and Pupil Diameter Using Eye-Tracking Technology

Purpose The purpose of this study was to determine the reliability of interpupillary distance (IPD) and pupil diameter (PD) measures using an infrared eye tracker and central point stimuli. Validity of the test compared to known clinical tools was determined, and normative data was established against which individuals can measure themselves. Methods Participants (416) across various demographics were examined for normative data. Of these, 50 were examined for reliability and validity. Validity for IPD measured the test (RightEye IPD/PD) against the PL850 Pupilometer and the Essilor Digital CRP. For PD, the test was measured against the Rosenbaum Pocket Vision Screener (RPVS). Reliability was analyzed with intraclass correlation coefficients (ICC) between trials with Cronbachs alpha (CA) and the standard error of measurement for each ICC. Convergent validity was investigated by calculating the bivariate correlation coefficient. Results Reliability results were strong (CA > 0.7) for all measures. High positive significant correlations were found between the RightEye IPD test and the PL850 Pupilometer (P < 0.001) and Essilor Digital CRP (P < 0.001) and for the RightEye PD test and the RPVS (P < 0.001). Conclusions Using infrared eye tracking and the RightEye IPD/PD test stimuli, reliable and accurate measures of IPD and PD were found. Results from normative data showed an adequate comparison for people with normal vision development. Translational Relevance Results revealed a central point of fixation may remove variability in examining PD reliably using infrared eye tracking when consistent environmental and experimental procedures are conducted.

The effects of body-borne loads and cadence manipulation on patellofemoral and tibiofemoral joint kinetics during running

Understanding how body-borne mass influences knee loads during running and how to modulate these knee loads may assist efforts to reduce the high rate of knee injuries in military populations. We tested a) the extent a 15-kg body-borne load affects peak and cumulative patellofemoral (PFJ) and tibiofemoral (TFJ) contact forces during running and b) if a 7.5% increase in running cadence modulates these contact forces. Compared with unloaded running, the body-borne load increased peak PFJ contact force (+0.2 body weights; p=0.001) and PFJ impulse (+32 body weights per km; p<0.001). Additionally, greater peak total TFJ contact force (+0.5 body weights; p<0.001) and greater peak medial TFJ contact force (+0.4 body weights; p=0.002) resulted with the added load. Similarly, 85 additional body weights of total TFJ impulse per km (p<0.001) and 65 additional body weights of medial TFJ impulse per km (p<0.001) were noted with the added load. The higher cadence condition reduced peak PFJ force (-0.5 body weights, p<0.001) and PFJ impulse per km (-15 body weights per km, p<0.016). Reduced peak total and peak medial TFJ contact forces (-0.8 body weights, p<0.001; -0.5 body weights, p<0.001, respectively) were also found with higher cadence, while reduced total TFJ and medial TFJ impulse per km (-18.5 body weights per km, p<0.001; -12.2 body weights per km, p<0.001, respectively) were observed. Thus, running with increased cadence eliminated increased knee loads per step but only partially reduced the greater cumulative knee loads per km that resulted with an added 15-kg body-borne load.

The Effect of Prior Tennis Experience on Wheelchair Tennis Players’ Visual Search

The purpose of this study was to examine whether prior biped tennis playing experience results in different visual search strategies compared with no prior biped playing experience. A total of 32 wheelchair (WC) tennis players, 17 males and 15 females, ranked between 1 and 16 on the International Tennis Federation rankings participated in this study. Half the players had prior experience playing tennis as a biped player, and half had no prior experience in biped tennis. The athletes viewed 18 different serves from an expert WC player while their gaze was monitored using eye tracking. Results revealed significant differences between the groups in fixation duration and number of fixations. Differences were also found in fixation locations and durations across biomechanical phases of the serve. The WC only players had more fixations for shorter periods than did WC with biped players in the ritual phase. In the preparatory and execution phases, however, the WC only players had fewer fixations for longer duration than the WC with biped players. Results are discussed in terms of long-term memory structures, learning, and considerations when coaching and training WC tennis players.

Creativity Dancing on the Boundaries between Fine Art, Human Performance and Space

Using an eye-tracker to record gaze patterns of viewers, this exploratory, interdisciplinary study examined how the use of priming questions affected the gaze patterns of museum visitors as the visitors looked at paintings and one sculpture. The data was shared with participants to engage them in the research process. The study demonstrated that gaze patterns changed in relation to the type of question the viewers were asked. Reflective questions elicited an open gaze; fact-finding questions produced a direct gaze dependent on the configuration of the image. Viewers enjoyed becoming aware of their biological behavior during the aesthetic experience of viewing the paintings.