Tactile localization of the direction and distance of sounds

In a previous paper, experiments were reported which demonstrated that human subjects can judge accurately the azimuthal direction of sounds using a tactile localization device. It was also demonstrated that a tactile analogue of selective auditory attention was possible with this system. Three additional experiments, reported here, indicate that subjects are also able to judge the distance of the sound source and can concurrently judge both the azimuthal direction and distance of a source. Comparisons were made between conditions where head movements were permitted lactive~ and conditions where the head was held still Ipassive, and between normal auditory judgments and tactile judgments. Active tactile performance was essentially similar to auditory performance. Active performance was superior to passive in both directional and distance judgment, but different components of the motor-sensory complex were found to contribute to active superiority in the two tasks. The implication of these experiments for the design of auditory prosthetic devices is discussed.     

Intersensory conflict between vision and touch: the response modality dominates when precise, attention-riveting judgments are required

In four experiments, reducing lenses were used to minify vision and generate intersensory size conflicts between vision and touch. Subjects made size judgments, using either visual matching or haptic matching. In visual matching, the subjects chose from a set of visible squares that progressively increased in size. In haptic matching, the subjects selected matches from an array of tangible wooden squares. In Experiment 1, it was found that neither sense dominated when subjects exposed to an intersensory discrepancy made their size estimates by using either visual matching or haptic matching. Size judgments were nearly indentical for conflict subjects making visual or haptic matches. Thus, matching modality did not matter in Experiment 1. In Experiment 2, it was found that subjects were influenced by the sight of their hands, which led to increases in the magnitude of their size judgments. Sight of the hands produced more accurate judgments, with subjects being better able to compensate for the illusory effects of the reducing lens. In two additional experiments, it was found that when more precise judgments were required and subjects had to generate their own size estimates, the response modality dominated. Thus, vision dominated in Experiment 3, where size judgments derived from viewing a metric ruler, whereas touch dominated in Experiment 4, where subjects made size estimates with a pincers posture of their hands. It is suggested that matching procedures are inadequate for assessing intersensory dominance relations. These results qualify the position (Hershberger & Misceo, 1996) that the modality of size estimates influences the resolution of intersensory conflicts. Only when required to self-generate more precise judgments did subjects rely on one sense, either vision or touch. Thus, task and attentional requirements influence dominance relations, and vision does not invariably prevail over touch.     

Effect of ecological viewing conditions on the Ames' distorted room illusion

Ecological theory asserts that the Ames' distorted room illusion (DRI) occurs as a result of the artificial restriction of information pickup. According to Gibson (1966, 1979), the illusion is eliminated when binocular vision and/or head movement are allowed. In Experiment 1, to measure the DRI, we used a size-matching technique employing discs placed within an Ames' distorted room. One hundred forty-four subjects viewed the distorted room or a control apparatus under four different viewing conditions (i.e., restricted or unrestricted head movement), using monocular and binocular vision. In Experiment 2, subjects viewed binocularly and were instructed to move freely while making judgments. Overall, the main findings of this study were that the DRI decreased with increases in viewing access and that the DRI persisted under all viewing conditions. The persistence of the illusion was felt to contradict Gibson's position.     

Eye position and visual attention influence perceived auditory direction

The singular and joint effects of eccentric visual fixation and peripheral visual attention upon the perceived auditory median plane (PAMP) of the head were examined in four subjects. They positioned a hidden, horizontally-moving sound source to the perceived median plane of the head, while fixating a light 20 degrees or 45 degrees to the right or left of the actual median plane, and attending to another light in peripheral vision. Analysis by multiple linear regression yielded a model for each subject which indicated the nature and weighting of those factors contributing to variance reduction in PAMP judgments. Three subjects showed a strong linear attention effect, resulting in shifts of the PAMP away from the locus of attention. Similarly, a strong linear fixation effect was discovered in two subjects, a weak effect in another, and a nonlinear, inverse fixation effect in the last. Additional factors were noted for some subjects. Possible explanations of the observed effects were discussed. The study indicates that both visual attention and visual fixation are critical factors in experiments on auditory space perception although inter-individual differences do exist in the nature and strength of the effects.     

Sensitivity to perspective structure while walking without vision

Experiments are reported of the nonvisual sensitivity of observers to their paths of locomotion and to the resulting changes in the structure of their perspectives, ie changes in the network of directions and distances spatially relating them to objects fixed in the surrounding environment. In the first experiment it was found that adults can keep up to date on the changing structure of their perspectives even in the absence of sights and sounds that specify changes in self-to-object relations. They do this rapidly, accurately, and, according to the subjects' reports, automatically, as if perceiving the new perspective structures. The second experiment was designed to investigate the role of visual experience in the development of sensitivity to occluded changes in perspective structure by comparing the judgments of sighted adults with those of late-blinded adults (who had extensive life histories of vision) and those of early-blinded adults (who had little or no history of vision). The three groups performed similarly when asked to judge perspective while imagining a new point of observation. However, locomoting to the new point greatly facilitated the judgments of the sighted and late-blinded subjects, but not those of the early-blinded subjects. The findings indicate that visual experience plays an important role in the development of sensitivity to changes in perspective structure when walking without vision.     

Further experiments on the perception of growth in three dimensions

Mark and Todd (1983) reported an experiment in which the cardioidal strain transformation was extended to three dimensions and applied to a three-dimensional (3-D) representation of the head of a 15-year-old girl in a direction that made the transformed head appear younger to the vast majority of their subjects. The experiments reported here extend this research in order to examine whether subjects are indeed detecting cardioidal strain in three dimensions, rather than detecting changes in head slant or making 2-D comparisons of the shape of the occluding contour. Three-dimensional surfaces were obtained by measuring a real head manually (Experiment 1) and with a laser scanner (Experiment 2), and transformed to different age levels using the 3-D strain transformation described by Mark and Todd (1983). There were no statistically significant differences in the accuracy with which relative age judgments could be made in response to pairs of profiles, pairs of 3/4 views, or pairs of mixed views (profile plus 3/4 view), suggesting that subjects can indeed extract the cardioidal strain level of the head in three dimensions. However, an additional effect that emerged in these studies was that judgments were crucially affected by the instructions given to subjects, which suggests that factors other than cardioidal strain are important in making judgments about rich data structures.     

Psychophysics of perceiving eye-gaze and head direction with peripheral vision: implications for the dynamics of eye-gaze behavior

Two psychophysical experiments are reported, one dealing with the visual perception of the head orientation of another person (the 'looker') and the other dealing with the perception of the looker's direction of eye gaze. The participant viewed the looker with different retinal eccentricities, ranging from foveal to far-peripheral viewing. On average, judgments of head orientation were reliable even out to the extremes of peripheral vision (90 degrees eccentricity), with better performance at the extremes when the participant was able to view the looker changing head orientation from one trial to the next. In sharp contrast, judgments of eye-gaze direction were reliable only out to 4 degrees eccentricity, signifying that the eye-gaze social signal is available to people only when they fixate near the looker's eyes. While not unexpected, this vast difference in availability of information about head direction and eye direction, both of which can serve as indicators of the looker's focus of attention, is important for understanding the dynamics of eye-gaze behavior.     

Tactile discrimination of competing sounds

Discriminably different sounds, concurrently presented from the left and right of the medial plane, were reduced in angular separation until subjects could no longer detect which sound was “left” and which was “right.” The procedure was repeated with hearing masked and judgments made on the basis of the tactile signals at two fingertip vibrators that received their inputs from two miniature microphones bilaterally located on the subject’s head. Auditory and tactile performance were compared under active (head movements permitted) and passive (head held still) conditions. Active and passive performance were not significantly different. Auditory and tactile performance became no better than chance at angular separations of 2.7° and 4.4°, respectively. Touch compared sufficiently well with audition to support arguments for the inclusion of sound localization information in devices which use the skin as a substitute for the ear. nt]mis|This research was conducted at the Smith-Kettlewell Institute of Visual Sciences, San Francisco, California. This institute provided the apparatus for the experiment. B. L. Richardson was on Staff Development Leave from the Applied Psychology Department of the Caulfield Institute of Technology, Melbourne, Australia.     

Stimulus context and absolute magnitude estimation: a study of individual differences

The effect of stimulus context on absolute-magnitude-estimation (AME) judgments was examined by determining whether the loudness judgment of a tone is influenced by the intensities of other tones presented within the session. A group of 18 subjects was tested in separate sessions in which they judged stimuli within either a low (10-60 dB SL) or a high (40-90 dB SL) range of intensities. Examination of the results of individual subjects revealed that judgments of stimuli common to the two ranges were, in most subjects, unaffected or only slightly affected by the position of the range. The judgments of 2 subjects who failed to follow the instructions, however, showed very large context effects due to changing the stimulus range. The results of a second experiment, in which 22 subjects judged the loudness of tones within either a narrow (35-65 dB SL) or a wide (20-80 dB SL) range, revealed that, in all but 1 subject, the width of the range had no systematic effect on the loudness judgments of stimuli common to both ranges. This was also true 1 month later when 16 of the subjects returned to the laboratory to judge the loudness of tones within an even wider range of 10-90 dB SL. It was concluded that AME judgments are relatively insensitive to the potential biasing influences of stimulus context.     

时序信息和空间信息在工作记忆中的分离存储

采用相对新近性判断范式（judgments of relative recency）,通过三个实验探讨了工作记忆中时序信息和空间信息的存储方式及其关系。实验一比较了有无空间线索两种条件下时序信息的记忆绩效,结果发现,有无空间线索并不影响对时序信．E-的记忆。实验二和实验三通过控制刺激呈现的视野范围和减少呈现位置的不确定性来利化空间线索,结果表明,时序信息的记忆绩效也不受空间线索的影响。由此推论,工作记忆中的时序信息和空间信息是分离编码存储的,加入空间线索并不能提高时序信息的记忆绩效。     

Sensory conflict in judgments of spatial direction

Artificial discrepancy was created between information about azimuth coming from different sense modalities. The resolution of this discrepancy was examined for the cases of vision and proprioception, proprioception and audition, and vision and audition. Vision biases proprioceptive and auditory judgments. Proprioception biases auditory judgments and has a small effect on visual judgments. The results suggest that the combinations of sense modalities do not behave as an integrated system and the data are interpreted as indicating that different processes are involved in the resolution of discrepant directional information from different pairs of modalities.     

Influences of head and torso movement before and during affordance perception

Previous research has shown that body sway (both standing and seated) is related to the accuracy of affordance judgments. The authors investigated the influence of seated head and torso movement on the perception of a novel affordance for wheelchair locomotion. Healthy adults without prior wheelchair experience judged the lowest lintel under which they could roll in the wheelchair. Prior to judgments, participants were given brief (≈ 2 min) practice at self-controlled wheelchair locomotion. During practice, the participant's head either was or was not restrained within the wheelchair. During the subsequent judgment session, the participant's head was or was not restrained. The accuracy of affordance judgments was influenced by restraint during the practice session and also by restraint during the judgment session. The authors collected data on head movement during the judgment session (when participants were not restrained). These data revealed that movement during judgment sessions was influenced by whether or not participants were restrained during the practice session. Overall, the results reveal that the availability of head movements (i.e., being unrestrained) and the nature of head movements (during unrestrained judgment sessions) were causally related to the accuracy of affordance judgments.     

The influence of the acoustic context on vertical sound localization in the median plane

The influence of background sounds (frames) on vertical localization of single sound sources (targets) was examined in four experiments. Loudspeakers (five targets and four frames) were positioned in the median plane, ranging from +30 degrees to -30 degrees above and below the subject's ear level. The subjects determined the vertical position of the targets by either verbal judgments or manual pointing. Frame and target sounds were presented concurrently or successively with a 1-sec interval; both consisted of (1) 300-Hz square waves, (2) noise, or (3) targets of noise and frames of 300-Hz square waves. Particularly in the second condition, the subjects consistently shifted the apparent target positions away from the frame locations. This contrast effect persisted even 1 sec after the offset of the frames. No effect was found with different waveforms for the frame and the target. Results are related to recent findings indicating a similar effect in the azimuthal dimension. Possibly the effect is based on a mechanism in which the auditory system adapts to recently heard sound source positions.     

Prediction and judgment as indicators of sensitivity to covariation of continuous variables

The present study used both judgments of strength of relationship and measures of the ability to predict one variable from another to assess subjects’ sensitivity to the covariation of two continuous variables. In addition, one group of subjects judged strength of relationship after merely observing the presentation of 60 pairs of two-digit numbers, and a second group made strength judgments after being actively engaged in predicting one member of a pair when given the other. The prediction and judgment data provide different pictures of subjects’ sensitivity to covariation. The subjects were quite poor at estimating strength of relationship but, by some measures, good at predicting one variable from another. Judgments were not strongly influenced by whether subjects had previously engaged in overt prediction. The implications of these results for the literature on covariation estimation are discussed.     

The effects of lexical and semantic information on same-different visual comparison of words

Previous research has indicated that phonemic and orthographic factors cannot account for the fact that words (clear/clear) are responded to more rapidly than orthographically legal nonwords (creal/creal) in a same-different visual comparison task. However, the role of semantic and lexical factors is less certain. The effects of semantic similarity on both same and different judgments were evaluated in several experiments. In the first experiment, subjects were not any slower on semantically related (rang/rung) than on unrelated (rang/rank) different judgments even with a 3,000-msec interval between the first and second word. In Experiment 2, subjects based their judgments on whether or not the first letter of each word was visually identical. Same judgments were not any faster for semantically related than unrelated items even though other evidence indicated that subjects were processing the whole word and not just the first letter. Experiment 3 showed that the word/orthographically legal nonword difference could be replicated with the first-letter visual comparison task employed in Experiment 2. These and related results were discussed with reference to the idea that the word/orthographically legal nonword difference is due to the facilitating effects of a lexical entry upon the encoding, but not the comparison of an item.     

Similarity and preference judgments of musical stimuli

Two experiments were performed comparing similarity (technical-structural) and preference personal-affective) judgments of jazz improvizations (Experiment 1) and of classical, pop-rock, and jazz music (Experiment 2). A multidimensional scaling paradigm (INDSCAL) was used for pairwise comparisons of the 12 musical pieces in each experiment. Each 2 minute piece was subdivided into 10 second segments in order to reduce fatigue or boredom and provide better sampling across comparison trials. In general, similarity dimensions reflected greater agreement among the subjects that did preference dimensions and were hierarchically ordered. The dominant dimensions for both similarity and preference judgments of jazz improvizations were: Tempo, Dominant Instrument (Horns-guitar), and Articulation. The dominant dimensions for similarity judgments involving all three genres were: Classical-Contemporary, Jazz-Rock, and Tempo. The dominant dimensions for preference judments were: Rock-Classical, Jazz-Classical, and Tempo. In general, the preference judgments of musically sophisticated subjects were less constrained by salient dimensions.     

Mechanisms Controlling Head Stabilization in the Elderly During Random Rotations in the Vertical Plane

Frequency-related response characteristics of the mechanisms controlling stabilization of the head in 10 elderly subjects were compared with response characteristics in 8 young adults. Angular velocity of the head with respect to the trunk and EMG responses of 2 neck muscles were recorded in 10 seated subjects during pseudorandom rotations of the trunk in the sagittal plane at frequencies of 0.35 to 3.05 Hz. Subjects were required to actively stabilize their heads with (VS) and without (NV) visual feedback so that voluntary mechanisms and the influence of vision could be tested. Reflex mechanisms were examined when subjects were distracted by a mental calculation task during rotations in the dark (MA). Age emerged as an influential factor in the performance of head stabilization mechanisms, and decrements in performance were even more pronounced in the older as compared with younger elderly subjects. Age effects could be seen in the (a) diminished ability to voluntarily stabilize the head, particularly with the absence of vision, (b) impaired ability to stabilize the head when cognitively distracted, and (c) appearance of a resonant response of the head. Control of head stabilization shifted from reflex mechanisms to system mechanics, probably as a result of age-related changes in the integrity of the sensory systems. The elderly's system mechanics could not effectively compensate for the disturbances, however, and instability was the result.     

Mechanisms controlling head stabilization in the elderly during random rotations in the vertical plane

Frequency-related response characteristics of the mechanisms controlling stabilization of the head in 10 elderly subjects were compared with response characteristics in 8 young adults. Angular velocity of the head with respect to the trunk and EMG responses of 2 neck muscles were recorded in 10 seated subjects during pseudorandom rotations of the trunk in the sagittal plane at frequencies of 0.35 to 3.05 Hz. Subjects were required to actively stabilize their heads with (VS) and without (NY) visual feedback so that voluntary mechanisms and the influence of vision could be tested. Reflex mechanisms were examined when subjects were distracted by a mental calculation task during rotations in the dark (MA). Age emerged as an influential factor in the performance of head stabilization mechanisms, and decrements in performance were even more pronounced in the older as compared with younger elderly subjects. Age effects could be seen in the (a) diminished ability to voluntarily stabilize the head, particularly with the absence of vision, (b) impaired ability to stabilize the head when cognitively distracted, and (c) appearance of a resonant response of the head. Control of head stabilization shifted from reflex mechanisms to system mechanics, probably as a result of age-related changes in the integrity of the sensory systems. The elderly's system mechanics could not effectively compensate for the disturbances, however, and instability was the result.     

关于pCI与因果判断的实验研究

本研究通过三个实验,检验了pCI公式对人类因果判断预测的准确性。实验结果发现,被试的判断与pCI的预测趋势基本一致,但（a＋d）／n的预测似乎更加准确;被试的判断较pCI而言波动较小,且可能在开始判断时需要一段时间形成自己的判断标准或方法,之后的判断与精密的数学计算有共同之处;不同个体判断方式有比较大的差异,但是仍能归为一些类型。     

Perceptually Equivalent Judgments Made Visually and via Haptic Sensory-Substitution Devices

ABSTRACT

According to the ecological theory of perception–action, perception is primarily of affordances, which are directly perceivable opportunities for behavior. The current study evaluated participants’ ability to use vision and haptic sensory-substitution devices to support perceptual judgments of affordances involving the task of passing through apertures. Sighted participants made perceptual judgments about whether they could walk through apertures of various widths and their level of confidence in each judgment, using unrestricted vision and, when blindfolded, using two haptic sensory-substitution instruments: a cane-like wooden rod and the Enactive Torch, a device that converts distance information into vibrotactile stimuli. The boundary between aperture widths that were judged as pass-through-able versus non-pass-through-able was statistically equivalent across sensory modalities. However, participants were not as confident in their judgments using the rod or Enactive Torch as they were using vision. Additionally, participants’ judgments with the haptic instruments were significantly more accurate than with vision. The results underscore the need to assess sensory-substitution devices in the context of functional behaviors.