Human non-visual discrimination of gradual turning is poor

We report three measures of the ability of normally sighted adults to discriminate turning while walking blindfolded outdoors. Constant error in selecting line drawings of paths indicated that participants under represent the amount of turning along more curved paths and over represent the amount of turning on less curved paths. Constant error in the direction of pointing to the origin of paths indicated a bias consistent with the direction of turning along more curved paths. Participants produced more accurate drawings of paths as the amount of turning increased. The results suggest that non-visual cues that accompany self movement are not sufficient for accurate representation of large radius curves in geographic scale travel.     

A three-dimensional biomechanical comparison between turning strategies during the stance phase of walking

Two main strategies for turning exist, the step and spin turns. A three-dimensional analytical comparison between these strategies has not been reported in the literature. Establishing differences between the two strategies is important if providing gait-training advice to clinical populations. The study is the first to compare 90 degrees spin and step turns on the basis of three-dimensional kinematic and kinetic analysis. The turns were free of constraints, thus participants knew when to turn resulting in feed-forward control. Two separate and distinct spin turn sub-strategies were used, the 'ipsilateral crossover' and 'ipsilateral pivot'. These turns required increased range of motion (RoM) in the transverse plane and greater muscular demand than the step turn. The step turn provided a number of advantages over the spin turns, such as keeping a wide base of support, it did not require increased co-ordination, RoM out of the sagittal plane and moments were generally less than the spin turns and no more demanding than straight gait. Further work involving many more participants is required to validate these initial findings.     

Lateral asymmetries of orientation to track control in extrapersonal space

In an initial experiment, subjects were asked to make simple lateral lever responses to left and right verbal and arrow directions with the preferred hand. No asymmetries were found. In two subsequent experiments, subjects guided a track through a left or right turn in one of four orientations under instructions which were direct, compass points, or physical referents, by either a rotary or a discrete control. Asymmetries of direction of turn were observed. Rotary control produced a response bias towards the body midline, but independently of this factor there was a powerful bias towards right turns of track direction in extrapersonal space. Discrimination in the horizontal plane was more difficult than in the vertical plane especially when the instructions were compass points. Within the horizontal plane, together with the bias to right turns of track direction, a bias towards the right of the display was present. The interaction of these factors is believed to underlie reported errors in route finding and direction giving situations.     

Strategies used for unconstrained direction change during walking

Full functional mobility requires adaptations, such as turning, to the basic straight locomotor pattern. The aim was to assess the mechanics of completing a complex turning manoeuvre. A full 3-dimensional kinematic and kinetic analysis of the ipsilateral limb was carried out during both straight gait and unconstrained turning through 90 degrees. 10 healthy university students participated. Analysis indicated that two distinctive substrategies of the spin turn-ipsilateral pivot and ipsilateral crossover-were employed. The ipsilateral pivot was the more dynamic turn and required two additional power phases at the ankle and hip to facilitate the pivot phase. The ipsilateral crossover uses a fall into the new direction. The spin turn is a more complex action than previously indicated.     

Directional preferences in turning behavior of girls and boys

Turning biases in humans and animals are known to be related to dopaminergic asymmetry between the brain hemispheres. A laboratory method, in which turning preference was evaluated, was adapted based upon the turning of the subject toward a particular sound in a square room. One of the aims of this study was to investigate the reliability of this method with children, and the other aim was to research the turning preference in boys and girls. 31 children between 7 and 13 yr. old volunteered as subjects, and 17 subjects were retested. The subjects tended significantly to turn leftward (60.1%), and fewer girls (53.7%) turned to the left than boys (66.2%). The correlation between the test and the retest was significant (r=.79, p< .01). Most studies have indicated that humans in childhood and adulthood exhibit left-turning preference, but conflicts between the results obtained on different types of rotation tasks have suggested that hemispheric dopaminergic activity might affect preference. That needs study.     

Spontaneous and learned turning behaviour in food- or water-restricted hooded rats

Some laboratory studies have suggested that whereas food restriction in animals leads to response alternation (behavioural flexibility), water restriction induces perseverative, stereotyped responding. Hooded rats, restricted to 1 hour per day access to either food or water, were tested on a radial-arm maze (using a procedure that eliminates algorithmic response strategies), for alternation in a 3-arm maze (both when the maze was familar and unfamilar, and with or without differential reward) and a 2-choice maze in which some animals were taught to alternate direction of turn, and others to perseverate. Both groups performed the radial-arm maze task competently and spontaneously alternated at a high rate. In the learned task, food-restricted rats were slower than water-restricted to reverse a consistent direction of turn; in the alternation condition, water-restricted rats developed a temporary, but strong, directional bias when making their first choice each day. Water-restricted subjects took water more readily than food-restricted took food when initially introduced to the apparatuses, but there was no consistent difference in motivation in the two conditions. The results provide little support for the notion that distinct cognitive-motivational states or behavioural strategies are induced by food- and water-restriction.     

Slower Reorientation of Trunk for Reactive Turning while Walking in Hemiparesis Stroke Patients

We examined the behavioral characteristics of reactive turning in hemiplegic stroke patients when they were informed of the turning direction just before turning was required at an unpredictable time. Eleven stroke patients and 20 healthy elderly control people were asked to initiate a turn as soon as a visual cue to inform them of the turning direction was activated unpredictably using a foot switch. Both the segmental reorientation and stepping type when turning 90° while walking were measured. The results indicated preserved segmental reorientation of the head and pelvis in stroke patients. Stroke patients showed delays in pelvic turning but not in head turning. Their delayed pelvic movement might be due to motor dysfunction and the time taken to ensure stability when deciding when to turn.     

Influence of body morphology on turning behavior in carnivores

The present work illustrates how three carnivore species with different body morphologies differ in the performance of a basic motor component-turning. Marbled polecats, which have an elongated and slender trunk, turn while sharply bending the trunk laterally. Grey wolves possess elongated legs and turn by maneuvering with their legs while slightly bending the trunk laterally and lowering the head to contact the ground. Honey badgers feature a wide and massive bear-like shape and rarely bend the trunk, but rather turn either by maneuvering with their legs or while elevating parts of the trunk in the vertical domain. It is suggested that these strategies shorten the radius of turning and thus reduce the moment of inertia. A lower moment of inertia may optimize turning behavior in terms of speed, energy cost, and the smoothness of transition between turning and bouts of forward progression or arrest.     

自由观看实景图片时注意的空间偏向

本研究采用眼动仪直接记录40名在校大学生及研究生（平均年龄21.9岁,SD=1.8）自由观看实景图片的眼动情况,考察自然状态下视觉注意在真实场景中的空间偏向。为了控制图片不同区域刺激特征显著性对结果的影响,将被试随机分为两组,一组观看正向图片,一组观看倒置图片。对图片四个象限上的首次注视概率、首次眼跳方向和注视时间百分比分别进行2（水平方向）×2（垂直方向）×2（呈现方式）的重复测量方差分析,结果表明,存在独立于刺激特征的空间注意偏向,表现在水平方向具有左侧注意偏向,垂直方向具有上侧注意偏向。     

The stability and interest consonance of lateral postural--motor biases in rats: results and implications

Each of six different tests of lateral postural-motor asymmetries was repeatedly administered to 126 rats. Directional reliability was found for rotatory swimming, open-field exploration, and stepping down from a beam. Neonatal posture, turn in an unbaited T maze, and orientation to tail pinch proved not to be reliable across days. The behavioral asymmetries in the open-field and step-down tests were directionally consonant with each other, but neither was related to the asymmetry exhibited in rotatory swimming, implying the existence of at least two independent asymmetrical neural substrates underlying the behaviors. Neither sample-wide directional biases nor major sex differences in bias were found. The sexes were, however, differentially influenced in direction on some tests by the number of males in their natal litters, implying a role for intrauterine exposure to androgens in predisposing rats toward some left- or right-biased behaviors.     

Memory of gender and gait direction from biological motion: Gender fades away but directions stay

The delayed discrimination methodology has been used to demonstrate a high-fidelity nondecaying visual short-term memory (VSTM) for so-called preattentive basic features. In the current Study, I show that the nondecaying high VSTM precision is not restricted to basic features by using the same method to measure memory precision for gait direction and gender-stereotypical gait patterns from high-level point-light walkers. Nondecaying VSTM of direction was found for delays up to 9 s whereas memory for gender decayed. For both tasks, reaction times (RTs) increased with the delay, but only gender RT took longer when the two walkers faced different directions to the line of sight as compared to when they faced the same direction. The results may reflect differences between local and global processes, or an ecologically valid strategy where VSTM resources focus on variables that change, such as tracking people's movements, rather than variables that are constant during short timescales, such as gender. (PsycINFO Database Record (c) 2012 APA, all rights reserved).     

Anticipatory Postural Adjustments for Altering Direction During Walking

The authors examined how individuals adapt their gait and regulate their body configuration before altering direction during walking. Eight young adults were asked to change direction during walking with different turning angles (0deg;, 45deg;, 90deg;), pivot foot (left, right), and walking speeds (normal and fast). The authors used video and force platform systems to determine participants' whole-body center of mass and the center of pressure during the step before they changed direction. The results showed that anticipatory postural adjustments occurred during the prior step and occurred earlier for the fast walking speed. Anticipatory postural adjustments were affected by all 3 variables (turn angle, pivot foot, and speed). Participants leaned backward and sideward on the prior step in anticipation of the turn. Those findings indicate that the motor system uses central control mechanisms to predict the required anticipatory adjustments and organizes the body configuration on the basis of the movement goal.     

Anticipatory postural adjustments for altering direction during walking

The authors examined how individuals adapt their gait and regulate their body configuration before altering direction during walking. Eight young adults were asked to change direction during walking with different turning angles (0 degree, 45 degree, 90 degree), pivot foot (left, right), and walking speeds (normal and fast). The authors used video and force platform systems to determine participants' whole-body center of mass and the center of pressure during the step before they changed direction. The results showed that anticipatory postural adjustments occurred during the prior step and occurred earlier for the fast walking speed. Anticipatory postural adjustments were affected by all 3 variables (turn angle, pivot foot, and speed). Participants leaned backward and sideward on the prior step in anticipation of the turn. Those findings indicate that the motor system uses central control mechanisms to predict the required anticipatory adjustments and organizes the body configuration on the basis of the movement goal.     

Processes of anticipatory postural adjustment and step movement of gait initiation

The purpose of this study was to elucidate whether the anticipatory postural adjustment (APA) and focal step movement of gait initiation are produced as a single process or different processes and whether the APA receives an inhibitory drive from the ongoing stop process of gait initiation. Healthy humans initiated gait in response to a first visual cue that instructed the initial swing leg. In some trials, a switch or stop cue was also provided after the first cue. When the stop cue was provided, participants withheld gait initiation. When the switch cue was provided, participants immediately switched the initial swing leg. In both the stop and switch tasks, the APA in response to the first cue, represented by the S1 period of the displacement of the center of pressure, appeared in more than half of the trials in which the withholding of gait initiation or switching of the initial swing leg was successfully completed. These findings indicate that the APA and focal step movement of gait initiation are produced as a dual process. In trials in which the APA in response to the first cue appeared, the amplitude and duration of the APA were decreased when the participants switched the initial swing leg or withheld gait initiation. This finding indicates that the ongoing stop process of gait initiation produces an inhibitory drive over the APA. The decreases in the amplitude and duration of the APA during the switching of the initial swing leg were similar to those during the withholding of gait initiation; moreover, the decreases during the switching of the initial swing leg were positively correlated with the decreases during the withholding of gait initiation. Thus, the stop processes during switching the initial swing leg and withholding gait initiation likely share a common inhibitory mechanism over the APA.     

Cognitive-versus-affective positivity asymmetries in thought systems

Positive-negative asymmetry in thought can involve both cognitive asymmetry, (thinking about characteristics that a stimulus has versus does not have), which we predict will be large and preponderantly a positivity bias, and affective asymmetry (thinking about desirable versus undesirable characteristics that the stimulus has or has not), predicted to be small and to fluctuate predictably in direction. The first four of the 10 studies reported here investigate asymmetries in thinking ability, measured by giving people directed-thinking tasks specifically asking them to generate positive versus negative thoughts. We predicted and found no affective asymmetry and a moderate-sized cognitive positivity bias that declines with practice. The second four of the 10 studies investigate asymmetries in proclivity (or preference beyond ability) that appear when people free associate on a variety of stimuli. As regards proclivity, we predicted and found a large, uniformly positive cognitive bias (that declines somewhat as children mature), but only a slight affective bias that is positive when autistic needs are dominant and negative when realistic needs dominate. A final pair of studies show that the cognitive and affective variables interact as regards how directed positive versus negative thinking about a stimulus affects evaluation of that stimulus.     

Effect of walking surface,late-cueing,physiological characteristics of aging,and gait parameters on turn style preference in healthy,older adults

Turning while walking is a crucial component of locomotion, often performed on irregular surfaces with little planning time. Turns can be difficult for some older adults due to physiological age-related changes. Two different turning strategies have been identified in the literature. During step turns, which are biomechanically stable, the body rotates about the outside limb, while for spin turns, generally performed with closer foot-to-foot distance, the inside limb is the main pivot point. Turning strategy preferences of older adults under challenging conditions remains unclear. The aim of this study was to determine how turning strategy preference in healthy older adults is modulated by surface features, cueing time, physiological characteristics of aging, and gait parameters. Seventeen healthy older adults (71.5 ± 4.2 years) performed 90° turns for two surfaces (flat, uneven) and two cue conditions (pre-planned, late-cue). Gait parameters were identified from kinematic data. Measures of lower-limb strength, balance, and reaction-time were also recorded. Generalized linear (logistic) regression mixed-effects models examined the effect of (1) surface and cuing, (2) physiological characteristics of ageing, and (3) gait parameters on turn strategy preference. Step turns were preferred when the condition was pre-planned (p < 0.001) (model 1) and when the gait parameters of stride regularity and maximum acceleration decreased (p = 0.010 and p = 0.039, respectively) (model 3). Differences in turn strategy selection under dynamic conditions ought to be evaluated in future fall-risk research and rehabilitation utilizing real-world activity monitoring.     

Field study on the behavior of right-turning vehicles in Malaysia and their contribution on the safety of unsignalized intersections

Behavior of right turning vehicles in the context of safety is characterized by their use of turning indicators and compliance with the stop rule. They are influence by the width of the carriageway and the variation in volume on the major road with respect to the traffic moving in the near and far side direction. Other factors affecting the behavior are the speed and spacing between vehicles moving on the major road. Lack of adequate past knowledge on the effect of geometric variation in terms of road width and directional variation in volume on the safety of unsignalized intersections have provided the motivation for this study. This paper focuses on the many factors that affect the behavior of right-turning vehicles resulting into conflicts. A brief account of the unique indigenous maneuver termed as the “Weaving Merging Right Turn” (WMRT) is provided and its effectiveness with respect to conventional right turn is evaluated. Data of 39,016 vehicles collected on 10 sites between January and June 2014 was analyzed. Multiple accidents were observed only on sites which had near side traffic volume greater than far side traffic volume. This result remains consistent with sites having single as well as multiple lanes per direction on the major roads. The number of conflicts for vehicles performing the WMRT was 2.5 times less as compared to the conventional right turn. Moreover WMRT was found to be the maneuver of choice for right turning motorcyclists with 60% of them opting for it over the conventional right turn on intersections having major road width less than 9 m. None of the motorcyclists, which were involved in a traffic conflict, were observed to use their turning indicator. Moreover none of the motorcyclists, which experienced a traffic conflict, were found to comply with the stopping rule at sites with major road width less than 9 m. On sites with major road width greater than 9 m, 45% of motorcyclists, involved in a traffic conflict, complied with the stopping rule as compared to 79% by vehicles other than motorcycles.     

Patterns of hemispheric perceptual asymmetries: left hemispatial biases predict changes in anxiety and positive affect in undergraduate women

Consistent with the tripartite model of anxiety and depression, hemispheric asymmetries may be differentially associated with depressive and anxious symptoms. Indeed, research has demonstrated that asymmetries do exist when examining hemispatial biases in both anxious and depressed individuals; however, the magnitude and direction of these asymmetries has been variable. The Chimeric Faces Task was used here to measure these asymmetries, along with measures for current and future levels of anxiety and depression. Results indicated that (a) increased left hemispatial biases at Time 1 predict increased anxiety (i.e., physiological hyperarousal) at Time 2 among female undergraduate students and (b) decreased left hemispatial biases at Time 1 predict decreased positive affectivity at Time 2 among the same participants. The possibility that hemispatial biases represent a vulnerability to future anxiety and depression is discussed.     

Attentional asymmetries in a visual orienting task are related to temperament

Spatial asymmetries are an intriguing feature of directed attention. Recent observations indicate an influence of temperament upon the direction of these asymmetries. It is unknown whether this influence generalises to visual orienting behaviour. The aim of the current study was therefore to explore the relationship between temperament and measures of spatial orienting as a function of target hemifield. An exogenous cueing task was administered to 92 healthy participants. Temperament was assessed using Carver and White's (1994) Behavioural Inhibition System and Behavioural Activation System (BIS/BAS) scales. Individuals with high sensitivity to punishment and low sensitivity to reward showed a leftward asymmetry of directed attention when there was no informative spatial cue provided. This asymmetry was not present when targets were preceded by spatial cues that were either valid or invalid. The findings support the notion that individual variations in temperament influence spatial asymmetries in visual orienting, but only when lateral targets are preceded by a non-directional (neutral) cue. The results are discussed in terms of hemispheric asymmetries and dopamine activity.     

Lexical decision and naming asymmetries: Influence of response selection and response bias

Signal detection measures were used to evaluate the effects of several response variables (manual vs. vocal, Go-NoGo vs. Yes-No) on lexical decision asymmetries. An unvarying right visual field advantage in discriminability (d') was observed in each condition. However, response criteria (beta) varied over visual fields and conditions. Naming and lexical decision were shown to have equivalent asymmetries when the effects of response bias are removed. The results indicate that postaccess decision processes make important contributions to lexical decision asymmetries.