Relation of sound intensity and accuracy of localization

Tests were carried out on 17 subjects to determine the accuracy of monaural sound localization when the head is not free to turn toward the sound source. Maximum accuracy of localization for a constant-volume sound source coincided with the position for maximum perceived intensity of the sound in the front quadrant. There was a tendency for sounds to be perceived more often as coming from a position directly toward the ear. That is, for sounds in the front quadrant, errors of localization tended to be predominantly clockwise (i.e., biased toward a line directly facing the ear). Errors for sounds occurring in the rear quadrant tended to be anticlockwise. The pinna's differential effect on sound intensity between front and rear quadrants would assist in identifying the direction of movement of objects, for example an insect, passing the ear.     

幼儿自豪的非言语行为表达编码系统编制

选取352名幼儿教师,对与幼儿自豪的非言语行为表达相关的2套图片进行识别.旨在确定幼儿自豪的非言语行为表达的动作成分和动作单元,并以此为基础编制编码系统.结果表明:(1)幼儿自豪的非言语行为表达包括4个方面7个动作成分,即Ⅰ微笑和大笑的面部表情,Ⅱ舒展的身体姿势,Ⅲ头稍微后倾的头部动作,Ⅳ双手叉腰、高举和在胸前握拳的手臂动作;(2)幼儿自豪的非言语行为表达包括12个动作单元;(3)幼儿自豪的非言语行为表达编码系统具有较高的信度和效度,可以作为测评幼儿自豪发展的工具.     

Absolute motion parallax and the specific distance tendency

In the absence of definitive cues’to distance, the perceived distance of an object will be in error in the direction of the object appearing at a distance of about 2 m from O. This tendency to perceive an object at a relatively near distance is termed the specific distance tendency (Gogel. 1969). Also, it has been found that an error in perceiving the distance of an object will result in an apparent movement of the object when the head is moved (Hay & Sawyer. 1969; Wallach, Yablick. & Smith. 1972). From these two results, it was expected that the direction of trie apparent movement of a stationary point of light resulting from head movement would vary predictably as a function of the physical distance of the point of light from O. This expectation was confirmed in an experiment in which both the perceived motion and perceived distance of the point of light were measured. The consequences of the study for the role of motion parallax in the perception of distance and for the reafference principle in the perception of object motion with head motion are discussed     

Minding gaps on the skin: Opposite bisection biases on forehead and back of one’s head

Humans perceive the world from an egocentric perspective, while being able to mentally take a third person’s perspective. Graphesthesia tasks revealed that letters written on the back of one’s own head are consistently perceived from an embodied perspective, while the perspective on one’s front is less consistent and often disembodied. We developed a cutaneous gap bisection task as a more discrete measure of the perspective on the body. In analogy to a visual pseudoneglect, we expected bisections to deviate toward the left ear when perceived from an embodied perspective. While this hypothesis was confirmed for gap bisections on the back, the results on the front suggest overall a disembodied perspective. Contrary to our expectation, this pattern was not predicted by the spontaneous perspective participants took in a graphesthesia task, indicating different cognitive mechanisms. We discuss these findings in the frame of the current literature on spatial attention and perspective taking.     

Let’s twist again! Embodiment effects in spatial judgments on human figures rotated along a vertical axis

We investigated whether individuals used mental rotation and embodiment for arm laterality judgments of human figures that were stepwise rotated from back view to front view along a vertical axis. In Experiment 1, figures’ heads were always shown in profile, while only the bodies were rotated. Judgments were faster and more correct when figures were presented in back view compared to front view, but the relation between reaction times (RTs) and rotation angles was not strictly linear. In addition, judgments on figures in anatomically possible postures were better than on figures in impossible postures. In Experiment 2, figures’ heads were turned together with their body. RTs and rotation angles were linearly related. Results suggest that individuals use both mental rotation and a more direct matching between their own body and that of the figures, when making arm laterality judgments of human figures that are rotated along a vertical axis.     

Gaze,head and eye movements during somersaults with full twists

Somersaults with or without twists are the most important elements in sports such as gymnastics or trampolining. Moreover, to perform elements with the highest possible difficulty gymnasts should show good form and execution during the flight phase. In order to ensure perfect body control and a safe landing, gaze behavior has been proven to be crucial for athletes to orientate in the air. As eye movement and head movement are closely coordinated, both must be examined while investigating gaze behavior. The aim of the current study is to analyze athletes' head motion and gaze behavior during somersaults with full twists. 15 skilled trampoline gymnasts performed back straight somersaults with a full twist (back full) on the trampoline. Eye movement and head movement were recorded using a portable eye-tracking device and a motion capture suit. The results indicate that gymnasts use the trampoline bed as a fixation point for orientation and control the back full, whereas the fixation onsets for athletes of a better performance class occur significantly later. A strong coordination between gymnasts' eye movement and head movement could be determined: stabilizing the gaze during the fixation period, the eyes move in combination with the head against the twisted somersault direction to counteract the whole body rotation. Although no significant differences could be found between the performance classes with regard to the maximum axial head rotations and maximum head extensions, there seems to be a trend that less skilled gymnasts need orientation as early as possible resulting in greater head rotation angles but a poorer execution.     

Contribution of upper trunk rotation to hand forward-backward movement and propulsion in front crawl strokes

The study aims to test three hypotheses: (a) the rotation of the upper trunk consists of roll, pitch and yaw of frequencies harmonic to the stroke frequency of the front crawl stroke, (b) the rotation of the upper trunk generates back-and-forth movements of the shoulders, which enhances the movements of the stroking arms, and (c) the angular velocities of roll, pitch and yaw are associated with hand propulsion (HP). Front crawl strokes performed by twenty male swimmers were measured with a motion capture system. The roll, pitch and yaw angles about the three orthogonal axes embedded in the upper trunk were determined as three sequential Cardan angles and their angular velocities were determined as the three respective components of the angular velocity. HP and the drag and lift components of HP (HP_D and HP_L) were estimated by the hand positions and the data from twelve pressure sensors attached on hands. The roll, pitch, and yaw angles were altered in frequencies harmonic to the stroke frequency during the front crawl stroke. Shoulders alternately moved back and forth due to the upper trunk rotation. In the pull phase the angular velocity of roll was correlated with HP_L (r = −0.62, p = 0.004). Based on the back-and-forth movements of the shoulders and roll motion relative to a hand movement, the arm-stroke technique of the front crawl swimming was discussed in terms of increasing the hand velocity and HP.     

An apparatus for the assessment of prepulse inhibition in the frog

A system for studying prepulse inhibition in the leopard frog is described herein. It entails a modification of an apparatus developed almost a century ago, by Yerkes, for his investigations of hearing in the frog. With the present system, a frog is restrained in a cylindrical vessel (constructed from a 35-mm film canister), and the canister is positioned in the apparatus so that the animal’s legs hang downward. A miniature solenoid is used to deliver a startle eliciting tap to the frog’s head, and the resulting leg movement is detected by an optical densitometer. In addition to providing a convenient way to restrain frogs, our system enabled us to, in part, replicate Yerkes’s basic procedures with these subjects. As did Yerkes, we found that an acoustic signal just prior to a tap on a frog’s head inhibits the leg movement that would otherwise be elicited.     

Adaptation to field displacement during head movement unrelated to the constancy of visual direction

Adaptation to vertical field displacements dependent on head turning about a vertical axis was demonstrated under two conditions, rapid training with 100 head movements and 1-h-long training with continuous head turning. The effect of rapid training was measured with the slant estimation method. Adaptation after the longer training was ascertained by comparing the uncertainty ranges for apparent target immobility before and after the adaptation period. Adaptation to field displacements in directions parallel to the plane of the head rotation obtained under corresponding conditions was also measured and found to be somewhat greater than adaptation to vertical field displacements. The result of work by Wallach and Frey that adaptation to field displacement in the direction with the head rotation is greater than to displacement against it was corroborated. While the previous result had, been obtained with rapid adaptation and with the slant estimation method, we confirmed it with 1-h training and by measuring the uncertainty ranges before and after the adaptation period.     

Mental rotation and handedness: differences in object-based and egocentric transformations

This study investigates mental rotation performance of right- and left-handers in object-based and egocentric mental rotation tasks using human body stimuli with an outstretched arm in front and back view. Previous literature suggests that right-handers show a slightly better mental rotation performance than left-handers. 42 participants, 14 left-handers and 28 right-handers, completed a mental rotation task with object-based and egocentric transformation of a human figure which was displayed either in front or back view. The main result was a three-way interaction between the factors “kind of transformation”, “handedness” and “view” in a way, that right-handers show significantly faster reaction times then left-handers in front view object-based transformations because of the additional in-depth rotation for front view stimuli. This difference disappeared in egocentric tasks due to the modification of onés own perspective to solve the task. The results of this study show that right-handers not generally outperform left-handers in mental rotation tasks but only if more cognitive resources are needed.     

Design and efficacy of a head-coil bite bar for reducing movement-related artifacts during functional MRI scanning

This article describes the design, construction, application, and effectiveness of a simple bite bar for use with an MRI whole-head coil to reduce head-movement-related artifacts during functional brain imaging. The device is comfortable to use and allows considerable flexibility in positioning the subject’s head. Eleven subjects were scanned while performing a motor-sequencing experiment with and without the bite bar. The bite bar was generally effective in reducing maximum head movement to less than 0.5 mm (translation) and 0.5° (rotation).     

When one sees what the other hears: Crossmodal attentional modulation for gazed and non-gazed upon auditory targets

Three experiments investigated the nature of visuo-auditory crossmodal cueing in a triadic setting: participants had to detect an auditory signal while observing another agent’s head facing one of the two laterally positioned auditory sources. Experiment 1 showed that when the agent’s eyes were open, sounds originating on the side of the agent’s gaze were detected faster than sounds originating on the side of the agent’s visible ear; when the agent’s eyes were closed this pat-tern of responses was reversed. Two additional experiments showed that the results were sensitive to whether participants could infer a hearing function on the part of the agent. When no ear was depicted on the agent, only a gaze-side advantage was observed (Experiment 2), but when the agent’s ear was covered (Experiment 3), an ear side advantage was observed only when hearing could still be inferred (i.e., wearing the hat) but not when hearing was inferred to be diminished (i.e., wearing a helmet). The findings are discussed in the context of inferential and simulation processes and joint attention mechanisms.     

The representation of uniform motion in vision

For veridical detection of object motion any moving detecting system must allocate motion appropriately between itself and objects in space. A model for such allocation is developed for simplified situations (points of light in uniform motion in a frontoparallel plane). It is proposed that motion of objects is registered and represented successively at four levels within frames of reference that are defined by the detectors themselves or by their movements. The four levels are referred to as retinocentric, orbitocentric, egocentric, and geocentric. Thus the retinocentric signal is combined with that for eye rotation to give an orbitocentric signal, and the left and right orbitocentric signals are combined to give an egocentric representation. Up to the egocentric level, motion representation is angular rather than three-dimensional. The egocentric signal is combined with signals for head and body movement and for egocentric distance to give a geocentric representation. It is argued that although motion perception is always geocentric, relevant registrations also occur at the three earlier levels. The model is applied to various veridical and nonveridical motion phenomena.     

A corpus of 714 full-color images of depth-rotated objects

A set of full-color images of objects is described for use in experiments investigating the effects of in-depth rotation on the identification of three-dimensional objects. The corpus contains up to 11 perspective views of 70 nameable objects. We also provide ratings of the “goodness” of each view, based on Thurstonian scaling of subjects’ preferences in a paired-comparison experiment. An exploratory cluster analysis on the scaling solutions indicates that the amount of information available in a given view generally is the major determinant of the goodness of the view. For instance, objects with an elongated front-back axis tend to cluster together, and the front and back views of these objects, which do not reveal the object’s major surfaces and features, are evaluated as the worst views.     

Your own face is no more precious than others’: Evidence from the simultaneous–sequential paradigm

In the present study, we tested the dominant notion that the processing of familiar faces takes place in an automatic, capacity-unlimited manner. To do so, we had participants perform the task of detecting their own face among others’ nonfamiliar faces. Importantly, either all of the search stimuli were presented simultaneously or two different subsets of the stimuli were presented sequentially. The results showed that the search performance benefited from sequential presentation, indicating that detecting one’s own face depends on a capacity-limited process. A similar pattern of results was found when participants searched for someone else’s face, although there was a decline in the overall performance. These findings suggest that the processes of detecting familiar and unfamiliar faces suffer from the capacity limit of visual perception to similar extents, challenging the notion of the automaticity of familiar-face processing.     

Refractoriness of on Extended Movement to Directional Change

An extended movement was used to compare the memory-drum and single-channel definitions of psychological refractoriness. The basic movement In response to the first signal (S₁) was a forward lunge and a concurrent arm swing through a target string. The response to the second signal (S₂) was a reversal of the original movement The interstimulus Interval (ISI) ranged from .10 – .70 sec. in .10-sec. steps. The hypothesis that refractoriness of the reversal movement would decrease as ISI shortened was confirmed by the fact that error frequencies decreased significantly and substantially with decreasing IS I. The availability of some residual capacity to deal with S₂ during the refractory period was also indicated by an examination of the relationship between RT₂ and the interval between S₂ and RT₁. This departure from the classical single-channel model shows some agreement with the neuromotor-programming theory.     

Integrating information from two pictorial animations: Complexity and cognitive prerequisites influence performance

Dividing visual attention between spatially distinct sources of information could either be beneficial (if there is too much information for a single visualization) or detrimental (if interrelated information has to be mentally re‐integrated) for learning. We present a new display technology allowing for the presentation of two distinct animations by avoiding split foci of visual attention: learners are able to switch between animations by moving their head. We examined how 84 naïve learners integrated information in three presentation modes: the ‘vexing‐image’ mode displaying two animations, participants being able to switch between them without shifting the visual focus, a classical ‘split‐screen’ and an ‘overlaid’ condition. Results showed that reduced complexity led to higher performance. Further, we showed that participants with high mental rotation abilities were best in the ‘split‐screen’ mode, whereas participants with low mental rotation abilities benefited most from the ‘vexing‐image’. Theoretical and instructional consequences of these findings are discussed. Copyright © 2010 John Wiley & Sons, Ltd.     

Motion aftereffects with horizontally moving sound sources in the free field

A horizontally moving sound was presented to an observer seated in the center of an anechoic chamber. The sound, either a 500-Hz low-pass noise or a 6300-Hz high-pass noise, repeatedly traversed a semicircular arc in the observer's front hemifield at ear level (distance: 1.5 m). At 10-sec intervals this adaptor was interrupted, and a 750-msec moving probe (a 500-Hz low-pass noise) was presented from a horizontal arc 1.6 m in front of the observer. During a run, the adaptor was presented at a constant velocity (-200 degrees to +200 degrees/sec), while probes with velocities varying from -10 degrees to +10 degrees/sec were presented in a random order. Observers judged the direction of motion (left or right) of each probe. As in the case of stimuli presented over headphones (Grantham & Wightman, 1979), an auditory motion aftereffect (MAE) occurred: subjects responded "left" to probes more often when the adaptor moved right than when it moved left. When the adaptor and probe were spectrally the same, the MAE was greater than when they were from different spectral regions; the magnitude of this difference depended on adaptor speed and was subject-dependent. It is proposed that there are two components underlying the auditory MAE: (1) a generalized bias to respond that probes move in the direction opposite to that of the adaptor, independent of their spectra; and (2) a loss of sensitivity to the velocity of moving sounds after prolonged exposure to moving sounds having the same spectral content.     

Rear negativity: Verbal messages coming from behind are perceived as more negative

Many studies have explored the evaluative effects of vertical (up/down) or horizontal (left/right) spatial locations. However, little is known about the role of information that comes from the front and back. Basing our investigations on multiple theoretical considerations, we propose that spatial location of sounds is a cue for message valence, such that a message coming from behind is interpreted as more negative than a message presented in front of a listener. Here we show across a variety of manipulations and dependent measures that this effect occurs in the domain of social information. Our data are most compatible with theoretical accounts which propose that social information presented from behind is associated with uncertainty and lack of control, which is amplified in conditions of self-relevance.     

A vocal response time system for use with sentence verification tasks

A software system for the reliable detection of vocal response onset is described. The system was designed specifically for the measurement of vocal response times to speech stimuli presented aurally in a sound field in the presence of some background noise. The response time extraction method described here is robust to masking noise and extraneous sounds that may be included in the subject’s recorded response. In addition, the response words do not have to be limited to a small set because the system is able to differentiate the onset of any speech sounds, including low-energy fricatives. The method described here may be implemented with any computer sound system because it relies only on the sound conversion clock for timing accuracy and uses postprocessing of the signal after acquisition for response extraction. The response time extraction technique as currently implemented does not recognize subject’s responses but could be incorporated into an automatic speech recognition system.