Attention, workload, and performance: A dual-task simulated shooting study

During skill execution, performers have been shown to attend to different aspects of movement, the external effects of one’s action, or to other environmental information. A variety of psychological mechanisms have been proposed to account for the differential outcomes when adopting each attentional strategy. However, there is limited information about the extent to which different attentional foci change the workload demands of task performance. To examine this, the current study administered the NASA-Task Load Index following a simulated shooting dual-task. Participants performed the primary shooting task alone (control), and also with a secondary task that directed attention toward an aspect of skill execution (skill-focused) and an unrelated environmental stimulus (extraneous focus). Primary and secondary task performances were significantly greater in the extraneous focus compared to the skill-focused dual-task. Also, workload was significantly lower during the extraneous focus compared to the skill-focused dual-task condition. Further analyses revealed that workload significantly mediated the effects of skill level on performance during the skill-focused and extraneous focus dual-tasks and various subscales of workload (i.e., temporal demand) contributed unique amounts of variance to this relationship. A discussion of the relationship between attention, workload and its subcomponents, skill level, and performance is presented

Postural control entropy is increased when adopting an external focus of attention

Falls in older adults are a public health challenge due to their influence on well-being and health-care costs. One way to address this challenge is to discover new methods to enhance postural control in older adults so they are better prepared to maintain an upright stance. Older and younger adults (N?=?32) performed a static balance task on a force plate with no instructions, internal focus instructions, or external focus instructions. Center of pressure displacement time series were analyzed using sample entropy and standard deviation. Only the external focus condition significantly increased postural control entropy, which was observed across both age groups. This study showed that an external focus of attention can be used to increase postural control entropy within a single session of testing

Interpretation of postural control may change due to data processing techniques

Postural control is commonly assessed by quantifying center of pressure (CoP) variability during quiet stance. CoP data is traditionally filtered prior to analysis. However, some researchers suggest filtering may lead to undesirable consequences. Further, sampling frequency may also affect CoP analysis, as filtering CoP signals of different sampling frequencies may influence variability metrics. This study examined the influence of sampling frequency and filtering on metrics that index the magnitude and structure of variability in CoP displacement and velocity. Healthy adults (N = 8, 27.4 ± 2.6 years) balanced on their right foot for 60 s on a force plate. CoP data recorded at 100 Hz was then downsampled and/or filtered (2nd order dual-pass 10 Hz low-pass Butterworth) to create six different CoP time series for each participant: (1) original, (2) filtered, (3) downsampled to 50 Hz, (4) downsampled to 25 Hz, (5) downsampled to 50 Hz and filtered, and (6) down-sampled to 25 Hz and filtered. Data were then analyzed using four common variability metrics (standard deviation [SD], root mean square [RMS], detrended fluctuation analysis a [DFA a], and sample entropy [SampEn]). Data processing techniques did not influence the magnitude of variability (SD and RMS), but did influence the structure of variability (DFA a and SampEn) in CoP displacement. All metrics were influenced by data processing techniques in CoP velocity. Thus, when interpreting changes in CoP variability, one must be careful to identify how much change is driven by the neuromotor system and how much is a function of data processing technique

Obstacle crossing in a virtual environment transfers to a real environment

Obstacle crossing, such as stepping over a curb, becomes more challenging with natural aging and could lead to obstacle-related trips and falls. To reduce fall-risk, obstacle training programs using physical obstacles have been developed, but come with space and human resource constraints. These barriers could be removed by using a virtual obstacle crossing training program, but only if the learned gait characteristics transfer to a real environment. We examined whether virtual environment obstacle crossing behavior is transferred to crossing real environment obstacles. Forty participants (n?=?20 younger adults and n?=?20 older adults) completed two sessions of virtual environment obstacle crossing, which was preceded and followed by one session of real environment obstacle crossing. Participants learned to cross the virtual obstacle more safely and that change in behavior was transferred to the real environment via increased foot clearance and alterations in foot placement before and after the real environment obstacle. Further, while both age groups showed transfer to the real environment task, they differed on the limb in which their transfer effects applied. This suggests it is plausible to use virtual reality training to enhance gait characteristics in the context of obstacle avoidance, potentially leading to a novel way to reduce fall-risk

An external focus of attention is effective for balance control when sleep-deprived

The purpose of our study was to examine if the beneficial effects of an external focus are effective for balance control when sleep-deprived. Sleep-deprived participants (27 hours awake) completed three blocks of five separate 30 second trials on a dynamic balance board. All participants were given internal, external, and control instruction. For the internal focus trials, participants focused on their feet; whereas, for the external focus trials, participants focused on the balance board. Participants’ time in balance was significantly greater during the external focus compared to the internal focus and control. These findings suggest that external focus instructions are effective when participants are sleep-deprived

The effects of low-intensity cycling on cognitive performance following sleep deprivation

This study examined the effect of 24 h of sleep deprivation on cognitive performance and assessed the effect of acute exercise on cognitive performance following sleep deprivation. Young, active, healthy adults (n = 24, 14 males) were randomized to control (age = 24.7 ± 3.7 years, BMI = 27.2 ± 7.0) or exercise (age = 25.3 ± 3.3 years, BMI = 25.6 ± 5.1) groups. Cognitive testing included a 5-min psychomotor vigilance task (PVT), three memory tasks with increasing cognitive load, and performance of the PVT a second time. On morning one, cognitive testing followed a typical night's sleep. Following 24-h of sustained wakefulness, cognitive testing was conducted again prior to and after the acute intervention. Participants in the exercise condition performed low-intensity cycling (~ 40%HRR) for 15-min and those in the control condition sat quietly on the bike for 15-min. t-Tests revealed sleep deprivation negatively affected performance on the PVT, but did not affect memory performance. Following the acute intervention, there were no cognitive performance differences between the exercise and rested conditions. We provide support for previous literature suggesting that during simple tasks, sleep deprivation has negative effects on cognitive performance. Importantly, in contrast to previous literature which has shown multiple bouts of exercise adding to cognitive detriment when combined with sleep deprivation, our results did not reveal any further detriments to cognitive performance from a single-bout of exercise following sleep deprivation

The influence of attentional focus on balance control over seven days of training

This study examined the training effect of attentional focus (external focus, internal focus, or no focus instructions) on a dynamic balance task. Participants completed baseline balance testing, seven consecutive days of dynamic balance board training, and retention testing 24 hours after the last session. The novel finding of this study was the presence of a training effect on balance control when adopting an external focus relative to an internal focus or no focus instructions. Further, we report the unique observation that more patterned behavior was adopted regardless of the focus instructions. These findings provide insight into how instructions can be altered to enhance human balance control and complement the constrained-action hypothesis

Postural control in older adults during and following a 12-week balance training intervention with attentional focus instructions

Adults (N?=?54, 80.78?±?6.08 years) who reported falling during the previous 12 months participated in a 12-week wobble board training program with internal focus or external focus (EF) instructions. Verbal manipulation checks were performed after training sessions as a self-report of the attentional foci used. The percentage of sessions in which participants reported using an EF (EFSR) was subsequently calculated. Mean velocity and mean power frequency in the anterior–posterior (MVELOAP and MPFAP) and medial–lateral (MVELOML and MPFML) direction were assessed during a 35-s wobble board task at Weeks 0, 6, 12, 13, 16, and 20, with the latter three as retention tests. Piecewise linear growth models estimated treatment effects on individual growth trajectories of MVELOAP and ML and MPFAP and ML during intervention and retention periods. Regardless of condition, MVELOML significantly decreased (p?=?-.0019, p?=?.005) and MPFML increased (p?=?.025, p?<?.02) during the intervention period. In analyses including interaction terms, participants in the EF group who reported greater EFSR had superior progression of MPFAP during the intervention (p?=?.0013, p?=?.025). Verbal manipulation checks suggest a preference for and advantage of EF for facilitating postural control performance and automaticity

Influence of practice schedules and attention on skill development and retention

Focus of attention during dual-tasks and practice schedules are important components of motor skill performance and learning; often studied in isolation. The current study required participants to complete a simple key-pressing task under a blocked or random practice schedule. To manipulate attention, participants reported their finger position (i.e., skill-focused attention) or the pitch of an auditory tone (i.e., extraneous attention) while performing two variations of a dual-task key-pressing task. Analyses were conducted at baseline, 10 min and 24 h after acquisition. The results revealed that participants in a blocked schedule, extraneous focus condition had significantly faster movement times during retention compared to a blocked schedule, skill focus condition. Furthermore, greatest improvements from baseline to immediate and delayed retention were evident for an extraneous attention compared to the skill-focused attention, regardless of practice schedule. A discussion of the unique benefits an extraneous focus of attention may have on the learning process during dual-task conditions is presented