Is gait-based visual regulation identical to gaze-based visual regulation in inexperienced athletes' long jump run-ups?

In long jumping, athletes need to hit a take-off board with both high precision and high run-up velocity to leap as far as possible. It is commonly agreed that visual regulation plays a crucial role in long jumping. To identify visual regulation, researchers have typically relied on analyses of variability in step parameters (i.e., “gait-based visual regulation”). The aim of the current study was to examine whether gait-based visual regulation coincides with measures of actual gaze control, referred to as “gaze-based visual regulation”. Therefore, 15 participants performed long jumps and run-throughs while wearing a mobile eye-tracker. To compare gait-based with gaze-based visual regulation, a digital camera recorded all trials for subsequent frame-by-frame analyses of step parameters. Results revealed that gait-based visual regulation coincided with the step of the longest gaze (i.e., dwell time) on the take-off board but not with the step of initial gaze on take-off board. This finding supports the notion of visuomotor control of motor variability by means of longer gazing periods at the take-off board. In addition, our results provide initial insights to coaches and athletes on the particular requirements of visual regulation and the relationship between gait and gaze in the long jump approach.     

The use of auditory feedback and edible reinforcement to decrease toe walking among children with autism

We replicated and extended previous research on the use of auditory feedback to decrease toe walking exhibited by 3 children with autism. After pretreatment screening analyses suggested that toe walking occurred independent of social consequences, we attached squeakers to the heels of each participants' shoes. The squeakers provided auditory feedback when participants walked appropriately (i.e., with a heel-to-toe gait). For all participants, the auditory feedback itself produced increases in appropriate walking. For 1 participant, this feedback was sufficient to reduce toe walking to clinically acceptable levels; however, for 2 other participants, delivery of edible items paired with the auditory feedback was necessary. Intervention effects maintained when the schedule for edible delivery was thinned for all participants. In addition, for 2 participants, effects maintained when the intervention was implemented in a different setting and with a different person with no edibles or a thin schedule of edibles.     

A comparison of the mechanical effect of arm swing and countermovement on the lower extremities in vertical jumping

The purposes of this study were to quantify and compare how arm swing and countermovement affect lower extremity torque and work during vertical jumping and to gain insight into the mechanisms that enable the arm swing and countermovement to increase jump height. Five participants maximally performed two types of vertical squat jumps with (SJA) and without (SJ) an arm swing and two types of countermovement vertical jumps with (CJA) and without (CJ) an arm swing. The participants jumped from a force platform and all performances were videotaped with a high-speed video camera (200Hz). Jump heights, joint torques and work were calculated by combining kinematic and kinetic data. It was found that of the four jumping conditions, the participants jumped highest when they used an arm swing with countermovement (i.e., CJA). The increase of the countermovement jump height with an arm swing is the result of the increase of the lower extremity work. In the hip joint, the increase in torque caused by the countermovement predominantly occurred at the beginning of the propulsion phase, while the increase in torque caused by the arm swing occurred in the rest of the propulsion phase. A key finding of our study is that arm swing and countermovement have independent effects on lower extremity work, and their effects are additive in CJA to produce greater jump height.     

Feedback consistency effects in visual and auditory word recognition: where do we stand after more than a decade?

The role of phonology-to-spelling consistency (i.e., feedback consistency) was investigated in 3 lexical decision experiments in both the visual and auditory modalities in French and English. No evidence for a feedback consistency effect was found in the visual modality, either in English or in French, despite the fact that consistency was manipulated for different kinds of units (onsets and rimes). In contrast, robust feedback consistency effects were obtained in the auditory lexical decision task in both English and French when exactly the same items that produced a null effect in the visual modality were used. Neural network simulations are presented to show that previous demonstrations of feedback consistency effects in the visual modality can be simulated with a model that is not sensitive to feedback consistency, suggesting that these effects might have come from various confounds. These simulations, together with the authors' results, suggest that there are no feedback consistency effects in the visual modality. In contrast, such effects are clearly present in the auditory modality. Given that orthographic information is absent from current models of spoken word recognition, the present findings present a major challenge to these models.     

Action effects in saccade control

According to the ideomotor principle, action preparation involves the activation of associations between actions and their effects. However, there is only sparse research on the role of action effects in saccade control. Here, participants responded to lateralized auditory stimuli with spatially compatible saccades toward peripheral targets (e.g., a rhombus in the left hemifield and a square in the right hemifield). Prior to the imperative auditory stimulus (e.g., a left tone), an irrelevant central visual stimulus was presented that was congruent (e.g., a rhombus), incongruent (e.g., a square), or unrelated (e.g., a circle) to the peripheral saccade target (i.e., the visual effect of the saccade). Saccade targets were present throughout a trial (Experiment 1) or appeared after saccade initiation (Experiment 2). Results showed shorter response times and fewer errors in congruent (vs. incongruent) conditions, suggesting that associations between oculomotor actions and their visual effects play an important role in saccade control.     

The owl and the pussycat: Gaze cues and visuospatial orienting

Recent research has shown that nonpredictive gaze cues trigger reflexive shifts in attention toward the looked-at location. But just how generalizable is this spatial cuing effect? In particular, are people especially tuned to gaze cues provided by conspecifics, or can comparable shifts in visual attention be triggered by other cue providers and directional cues? To investigate these issues, we used a standard cuing paradigm to compare the attentional orienting produced by different cue providers (i.e., animate vs. inanimate) and directional cues (i.e., eyes vs. arrows). The results of three experiments revealed that attentional orienting was insensitive to both the identity of the cue provider and the nature of the triggering cue. However, compared with arrows, gaze cues prompted a general enhancement in the efficiency of processing operations. We consider the implications of these findings for accounts of reflexive visual orienting.     

Using auditory feedback in body weight training

Auditory feedback has been successfully used to enhance performance in several sports such as golf and dance. The current study used auditory feedback procedures (i.e., a clicker) to improve the performance of 3 students performing a handstand. Handstands are part of a discipline called body weight training, that uses only the weight of an individual's own body to gain strength and body control. A multiple baseline design across four components was used to evaluate the effectiveness of auditory feedback. The results showed that auditory feedback was effective. The students and the trainer were highly satisfied with the auditory feedback procedure. Implications for future research are discussed.     

Prism Adaptation During Target Pointing From Visible and Nonvisible Starting Locations

The performance of subjects whose starting limb location was visible when pointing to a sagittal target during exposure to prismatic displacement showed immediate target acquisition, but aftereffects of exposure were absent. When starting limb location was not visible, accurate exposure performance was slow to develop, but aftereffects were substantial. Visible starting location evoked a zeroing-in control strategy on the basis of relative-location coding, which rapidly reduced performance error but disabled detection of spatial misalignment between sensorimotor systems. When starting location was not visible, absolute-location coding of the displaced target initiated movement that had to be corrected subsequently by visual feedback. In this case, comparison of the initial erroneous movement code with the limb location that achieved the target enabled misalignment detection and consequent realignment.     

Biofeedback augmenting lower limb loading alters the underlying temporal structure of gait following anterior cruciate ligament reconstruction

Biofeedback has recently been explored to target deviant lower extremity loading mechanics following anterior cruciate ligament reconstruction (ACLR) to mitigate the development of post traumatic osteoarthritis. The impact this feedback has on the structure of the stride interval dynamics—a barometer of gait system health—however, have yet to be examined. This study was designed to assess how feedback, used to alter lower-extremity loading during gait, affects the structure of stride interval variability by examining long-range stride-to-stride correlations during gait in those with unilateral ACLR. Twelve participants walked under three separate loading conditions: (1) control (i.e., no cue) (2) high loading, and (3) low loading. Baseline vertical ground reaction force (vGRF) data was used to calculate a target 5% change in vGRF for the appropriate loading condition (i.e., high loading was +5% vGRF, low loading was −5% vGRF). The target for the load condition was displayed on a screen along with real-time vGRF values, prescribing changes in stride-to-stride peak vertical ground reaction forces of each limb. From time-series of stride intervals (i.e., duration), we analyzed the mean and standard deviation of stride-to-stride variability and, via detrended fluctuation analysis (i.e., DFA α), temporal persistence for each feedback condition. Both the high and low loading conditions exhibited a change toward more temporally persistent stride intervals (high loading: α =0.92, low loading: α = 0.98) than walking under the control condition (α = 0.78; high vs. control: p = .026, low vs. control: p = .001). Overall, these results indicate that altering lower extremity load changes the temporal persistence of the stride internal dynamics in ACLR individuals, demonstrating the implications of the design of gait training interventions and the influence feedback has on movement strategies.     

Encoding location and serial order in auditory working memory: evidence for separable processes

In this study, we investigated the interactions between temporal and spatial information in auditory working memory. In two experiments, participants were presented with sequences of sounds originating from different locations in space and were then asked to recall either their position or their serial order. In Experiment 1, attention during encoding was manipulated by contrasting 'pure' blocks (i.e., location-only or serial-order-only trials) to 'mixed' blocks (i.e., different percentages of spatial and serial-order trials). In Experiment 2, 'pure' blocks were contrasted to blocks in which spatial and serial-order trials were intermixed with a third task requiring a semantic categorization of sounds. Results from both experiments showed that, whereas serial-order recall is linearly affected by the simultaneous encoding of a concurrent feature, the recall of position is mostly unaffected by concurrent feature encoding. Contrastingly, overall performance level was lower for spatial recall than serial recall. We concluded that serial order and location of items appear to be independently encoded in auditory working memory. Serial order is easier to recall, but strongly affected by the processing of concurrent item dimensions, while item location is more difficult to recall, but relatively automatic, as shown by its strong resistance to interfering dimensions in encoding.     

The impact of auditory continual feedback on take-overs in Level 3 automated vehicles

ObjectiveTo implement auditory continual feedback into the interface design of a Level 3 automated vehicle and to test whether gaze behavior and reaction times of drivers improved in take-over situations.BackgroundWhen required to assume manual control in take-over situations, drivers of Level 3 automated vehicles are less likely than conventional drivers to spot potential hazards, and their reaction time is longer. Therefore, it is crucial that the interface of Level 3 automated vehicles will be designed to improve drivers’ performance in take-over situations.MethodIn two experiments, participants drove a simulated route in a Level 3 automated vehicle for 35 min with one imminent take-over event. Participants’ gaze behavior and performance in an imminent take-over event were monitored under one of three auditory interface designs: (1) Continual feedback. A system that provides verbal driving-related feedback; (2) Persistent feedback. A system that provides verbal driving-related feedback and a persistent beep; and (3) Chatter feedback. A system that provides verbal non-driving-related feedback. Also, there was a control group without feedback.ResultsUnder all three auditory feedback designs, the number of drivers' on-road glances increased compared to no feedback, but none of the designs shortened reaction time to the imminent event.ConclusionIncreasing the number of on-road glances during automated driving does not necessarily improve drivers’ attention to the road and their reaction times during take-overs.ApplicationPossible implications for the effectiveness of auditory continual feedback should be considered when designing interfaces for Level 3 automated vehicles.     

Earwitness identification performance: the effect of language,target, deliberate strategies and indirect measures

The present study examined whether voice identification performance is influenced by language comprehension (i.e. familiar vs. non‐familiar language) and target presence (target‐present (TP) vs. target‐absent line‐ups (TA)). It also looked at the relationship of deliberate strategies and indirect measures (i.e. confidence, difficulty and pressure) with performance. Sixty Native English speakers were exposed to an auditory event involving 45 to 50 seconds of speech. After 30 minutes delay, participants listened to a voice line‐up (TP or TA) in either a familiar (i.e. English) or unfamiliar language (i.e. French) according to the language spoken during the event, and were then asked to identify the original speaker's voice. Participants demonstrated significantly better performance for the familiar language/TP line‐ups. Participants who reported using the ‘elimination’ strategy were significantly more accurate than participants who reported using either a ‘matching’ strategy or no strategy. Indirect measures were not found to be good predictors of performance, except for confidence regarding TA accuracy. Copyright © 2006 John Wiley & Sons, Ltd.     

Effects of direct and averted gaze on the perception of facially communicated emotion

Research has largely neglected the effects of gaze direction cues on the perception of facial expressions of emotion. It was hypothesized that when gaze direction matches the underlying behavioral intent (approach-avoidance) communicated by an emotional expression, the perception of that emotion would be enhanced (i.e., shared signal hypothesis). Specifically, the authors expected that (a) direct gaze would enhance the perception of approach-oriented emotions (anger and joy) and (b) averted eye gaze would enhance the perception of avoidance-oriented emotions (fear and sadness). Three studies supported this hypothesis. Study 1 examined emotional trait attributions made to neutral faces. Study 2 examined ratings of ambiguous facial blends of anger and fear. Study 3 examined the influence of gaze on the perception of highly prototypical expressions.     

Sensorimotor synchronization: the impact of temporally displaced auditory feedback

When subjects are asked to tap in synchrony to a regular sequence of stimulus events (e.g., clicks), performance is not perfect in that, usually, an anticipation of the tap is observed. The present study examines the influence of temporally displaced auditory feedback on the size of this anticipatory error. Whereas earlier studies have shown that this asynchrony exhibits a linear increase in size as a function of an increasing delay in such additional auditory feedback, this study compared the impact of shifting feedback forward in time (i.e., feedback presented before the tap) with that of delayed auditory feedback. Results showed that the impact of feedback displacement on the amount of asynchrony differed for positive and negative displacements. Delayed feedback led to an increase in asynchrony, whereas negative displacements had (almost) no effect. This finding is related to a model assuming that the various feedback components arising from the tap (tactile, kinesthetic, auditory) are integrated to form one central representation, and that the timing of this central representation arises from a linear combination of the components involved.     

Auditory feedback and memory for music performance: Sound evidence for an encoding effect

Research on the effects of context and task on learning and memory has included approaches that emphasize processes during learning (e.g., Craik & Tulving, 1975) and approaches that emphasize a match of conditions during learning with conditions during a later test of memory (e.g., Morris, Bransford, & Franks, 1977; Proteau, 1992; Tulving & Thomson, 1973). We investigated the effects of auditory context on learning and retrieval in three experiments on memorized music performance (a form of serial recall). Auditory feedback (presence or absence) was manipulated while pianists learned musical pieces from notation and when they later played the pieces from memory. Auditory feedback during learning significantly improved later recall. However, auditory feedback at test did not significantly affect recall, nor was there an interaction between conditions at learning and test. Auditory feedback in music performance appears to be a contextual factor that affects learning but is relatively independent of retrieval conditions.     

Listenmee® and Listenmee® smartphone application: Synchronizing walking to rhythmic auditory cues to improve gait in Parkinson’s disease

Evidence supports the use of rhythmic external auditory signals to improve gait in PD patients (Arias & Cudeiro, 2008; Kenyon & Thaut, 2000; McIntosh, Rice & Thaut, 1994; McIntosh et al., 1997; Morris, Iansek, & Matyas, 1994; Thaut, McIntosh, & Rice, 1997; Suteerawattananon, Morris, Etnyre, Jankovic, & Protas , 2004; Willems, Nieuwboer, Chavert, & Desloovere, 2006). However, few prototypes are available for daily use, and to our knowledge, none utilize a smartphone application allowing individualized sounds and cadence. Therefore, we analyzed the effects on gait of Listenmee®, an intelligent glasses system with a portable auditory device, and present its smartphone application, the Listenmee app®, offering over 100 different sounds and an adjustable metronome to individualize the cueing rate as well as its smartwatch with accelerometer to detect magnitude and direction of the proper acceleration, track calorie count, sleep patterns, steps count and daily distances. The present study included patients with idiopathic PD presented gait disturbances including freezing. Auditory rhythmic cues were delivered through Listenmee®. Performance was analyzed in a motion and gait analysis laboratory. The results revealed significant improvements in gait performance over three major dependent variables: walking speed in 38.1%, cadence in 28.1% and stride length in 44.5%. Our findings suggest that auditory cueing through Listenmee® may significantly enhance gait performance. Further studies are needed to elucidate the potential role and maximize the benefits of these portable devices.     

Look into my eyes: Gaze direction and person memory

The current research considered the effects of gaze direction on a fundamental aspect of social cogition: person memory. It was anticipated that a person's direction of gaze (i.e., direct or averted) would impact his or her subsequent memorability, such that recognition would be enhanced for targets previously displaying direct gaze. In Experiment 1, participants were presented with faces displaying either direct or averted gaze in a person‐classification (i.e., conceptual) task. Then, in a surprise memory test, they were required to report whether a presented face had been seen before. As expected, a recognition advantage was observed for targets displaying direct gaze during the initial classification task. This finding was replicated and extended in a second experiment in which participants initially reported the spatial location (i.e., perceptual task) of each face. We consider the implications of these findings for basic aspects of social‐cognitive functioning and person perception.     

Visual perception and gaze control in judging versus producing phase relations

We studied visual perception and gaze control in nine participants while they judged the relative phase between two oscillating stimuli (Experiment 1), and while they moved their hand--and therewith a concurrent feedback signal--in-phase or in antiphase with an oscillating stimulus (Experiment 2). As in previous studies, the mean relative phase judgements in Experiment 1 corresponded to the presented phase relations (0 degree, 45 degrees, 90 degrees, 135 degrees, and 180 degrees), whereas their standard deviations followed an inverted U-function of relative phase. The relative phase judgements were hardly affected by the degree of visibility (fully visible, inner parts occluded, outer parts occluded) and the amplitude (5 degrees, 10 degrees, and 20 degrees) of the stimuli. Stimulus-gaze coupling decreased as relative phase increased, and its variability correlated with that of the relative phase judgements. Taken together, task performance and gaze behaviour suggested that the judgement of relative phase might be flexibly based on different variables, rather than a single variable like relative direction of motion. In Experiment 2, the production of the antiphase relation was less stable than that of the in-phase relation. Performance deteriorated when the outer parts of the signals were occluded and when their amplitudes were reduced. Stimulus-gaze coupling was stronger during in-phase than during antiphase tracking and weaker when the signals were partially occluded and when their amplitudes were reduced. Stimulus-gaze coupling at 0 degrees and 180 degrees was stronger in Experiment 2 than in Experiment 1, suggesting that the visual perception of relative phase may benefit from its active production. Overall, the results clearly indicated that visual perception of relative phase and the corresponding gaze control are strongly task-dependent.     

Attention and gaze shifting in dual-task and go/no-go performance with vocal responding

Evidence from go/no-go performance on the Eriksen flanker task with manual responding suggests that individuals gaze at stimuli just as long as needed to identify them (e.g., Sanders, 1998). In contrast, evidence from dual-task performance with vocal responding suggests that gaze shifts occur after response selection (e.g., Roelofs, 2008a). This difference in results may be due to the nature of the task situation (go/no-go vs. dual task) or the response modality (manual vs. vocal). We examined this by having participants vocally respond to congruent and incongruent flanker stimuli and shift gaze to left- or right-pointing arrows. The arrows required a manual response (dual task) or determined whether the vocal response to the flanker stimuli had to be given or not (go/no-go). Vocal response and gaze shift latencies were longer on incongruent than congruent trials in both dual-task and go/no-go performance. The flanker effect was also present in the manual response latencies in dual-task performance. Ex-Gaussian analyses revealed that the flanker effect on the gaze shifts consisted of a shift of the entire latency distribution. These results suggest that gaze shifts occur after response selection in both dual-task and go/no-go performance with vocal responding.     

Effects of dichotic listening on gait domains of healthy older adults during dual-tasking: An exploratory observational study

BackgroundIdentification of the cognitive mechanisms behind gait changes in aging is a prime endeavor in gerontology and geriatrics. For this reason, we have implemented a new dual-task paradigm where an auditory attentional task is performed during over-ground walking. Dichotic listening assesses spontaneous attention and voluntary attention directed to right and left-ear. The uniqueness of dichotic listening relies on its requirements that vary in difficulty and recruitment of resources from whole brain to one brain hemisphere. When used in dual-tasking, asymmetric effects on certain gait parameters have been reported.ObjectivesThe present study aims to acquire a more global understanding on how dichotic listening affects gait domains. Specifically, we aimed to understand how spontaneous vs lateralized auditory attention altered the Principal Component Analysis (PCA) structure of gait in healthy older adults.MethodsSeventy-eight healthy older adults (mean age: 71.1 years; 44 women and 34 men) underwent the Bergen dichotic listening test while walking. As this study only focuses on the effects of the cognitive task on gait, only dual-task costs for gait were calculated and entered into the PCA analyses. We explored the PCA structure for the effects on bilateral gait parameters (i.e., both limbs together) as well as on lateralized gait parameters (i.e, separate parameters by limb). We first established gait domains during single-task walking. Then, dual-task cost scores for gait were entered in a series of PCAs.ResultsResults from the PCAs for bilateral gait parameters showed limited alterations on gait structure. In contrast, PCAs for lateralized data demonstrated modifications of the gait structure during dichotic listening. The PCAs corresponding for all dichotic listening conditions showed different factor solutions ranging between 4 and 6 factors that explained between 73.8% to 80% of the total variance. As a whole, all conditions had an impact on “pace”, “pace variability” and “base of support variability” domains. In the spontaneous attention condition, a six-factor solution explaining 78.3% of the variance showed asymmetrical disruptions on the PCA structure. When attention was focused to right-ear, a five-factor solution explaining 89% of the variance and similar to baseline was found. When attention was directed to left-ear, a four-factor solution explaining 73.8% of the variance was found with symmetrical impact on all factors.ConclusionsThese findings demonstrate for the first time that specific facets of attentional control affects gait domains both symmetrically and asymmetrically in healthy older adults.