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Perception of motion and position relative to the earth. An overview.

Results of the five experiments are consistent with the following generalizations. Canal-mediated turn perception (pitch, roll, or yaw) in earth-horizontal or earth-vertical plane, is suppressed in direct relationship to the magnitude of a linear acceleration vector lying in the plane of a responding canal when the magnitude of the linear vector is constant or increasing and when its direction is either fixed or rotating in the same direction as the concomitant canal signal. Canal-mediated turn perception (pitch, roll, or yaw) is not suppressed by a coplanar linear vector that is counterrotating relative to the canal signal. Change in perceived attitude (pitch, roll, or yaw) is very sluggish in the absence of concordant canal information; attitude change may not be an immediate otolith-mediated perceptual event but a slowly developing perception dependent upon cognitive appreciation of an immediate otolith angular position signal. Otolith phasic neural units, unreinforced by appropriate canal signals, may contribute more to a brief linear velocity component in perception than to rate of attitude change. Otolith-mediated attitude perception within a given earth-vertical plane can be distorted by strong coplanar angular velocity canal information. Once distorted, return to veridical attitude perception can be gradual because, in the absence of complimentary canal or visual information, recovery is dependent upon relatively slow cognitive appreciation of a prevailing otolith position signal. Several attractive hypotheses relating to the dynamics of attitude perception can only be tested by substantially more data on the dynamics of spatial orientation perception. Most of our objectives cannot be achieved without models that yield valid prediction of the dynamics of spatial orientation perception. All of the observations in these experiments were carried out in darkness, or, in the simulated catapult experiment, without external visual reference. Various forms of visual information will change the dynamics of spatial orientation perception. My discussion has been limited to consideration of the vestibular system, as though the canal and otolith systems completely controlled the dynamics of spatial orientation perceptions. Obviously other partners in the dynamics of postural control, including vision, proprioception, and expectation, must be included in this challenging field of research. Dedication to stereotyped ideas about objectivity in the 20th century has hindered advancement of knowledge on the dynamics of spatial orientation perception relative to rate of progress achieved by several scientists of the 18th and 19th centuries, who provided word pictures of perceived motions and tilts along with descriptions of the motions that engendered the pictures.(ABSTRACT TRUNCATED AT 400 WORDS)

Gravitation

[A study on the perception level of nursing activities of nurses in general hospitals].

The Study was carried out for the purpose of investigating the degree of perception in nursing activities. This study reports perceptions of nurses on the choices they make among competing activities, contrasts this perception with their opinion of what tasks they would like to spend time on. A sample of 231 clinical nurses was selected to participate in this study at two general hospitals in Seoul. The data was collected from July 10th to 25th, 1990. Subjects were instructed to rate one of five points likert type scale on the 43 items of nursing activities. Analysis of data was done by means of the SPSS-X Program using frequency, t-test and ANOVA. The results of this study were as follows; 1. The characteristics of the subjects were as follows: The age group of 25-29 years was 45.9%. For religion, Christians had the highest score, 68.4% and singles in subjects were 81.4%. For academic background, 64.5% were graduated from nursing junior colleges. In the subjects, staff nurses were 86.6%. 22.5% of them had worked for less than 1 year and 20.8% had 37 months to 5 years experience at the time of the survey. 62.8% were satisfied with the job. 2. The perception level of nursing activities: 1) The mean score for perception of professional nursing functions was 4.157 point, with a maximum score set at 5 points. The mean score for perception of priorities was 3.781. Perception of spending time was 3.932. 2) In perception of professional nursing functions, more important items were Aseptic technique (4.866), Shift and exchange of information concerning patients(4.654), Observing patients (4.799). Less important items were Transporting patients(3.411), Changing linens(3.442), Giving a bed shampoo (3.506). In priorities, more important ones were Aseptic technique(4.706), Shift and exchange of information concerning patients(4.524), Observing patients(4.390), Taking vital signs(4.355). And less important ones were Changing linens (3.100), Giving bed baths(3.113), Giving back rubs(3.121). In spending time, more important ones were Aseptic technique(4.706), Observing patients (4.532), Shift and exchange of information concerning patients(4.532). And less important ones were Changing lines(3.368), Transporting patients(3.394), Giving bed baths(3.450). 3) In the role perception level, the mean distribution of perception was 3.511-4.335; the role was perceived to be in order of frequency as a facilitator, coordinator, change agent and advocator role. The most important scale of factors by nursing activities was indirect nursing activities.

Adult

Human perception of horizontal trunk and head rotation in space during vestibular and neck stimulation.

The vestibular signal of head motion in space must be complemented by a neck signal of the trunk-to-head excursion in order to provide the individual with information on trunk motion in space. This consideration led us to study psychophysically the role of vestibular-neck interaction for human self-motion perception. Subjects (Ss) were presented with passive horizontal rotations of their trunk and/or head (sinusoidal rotations, f = 0.025 - 0.4 Hz) in the dark for vestibular and neck stimulation, as well as for combinations of both. Ss' perception was evaluated in terms of gain (veridical perception of stimulus magnitude, G = 1), phase, and detection threshold. (1) Perception of trunk rotation in space. During vestibular stimulation (whole-body rotation) and neck stimulation (trunk rotation with the head kept stationary) the frequency-transfer characteristics underlying this perception were very similar. The gain fell short; it was only about 0.7 at 0.4 and 0.2 Hz stimulus frequency and was further attenuated with decreasing frequency. In contrast, the phase was close to that of actual trunk position. The gain attenuation was found to be a function of the peak angular velocity of the stimulus, a fact, which we related to a 'velocity threshold' of the order of 1 deg/s. During the various vestibular-neck combinations used, Ss' perception was again erroneous, reflecting essentially the sum of its two non-ideal constituents. However, there was one noticeable exception; during the combination 'head rotation on stationary trunk', Ss veridically perceived their trunk as stationary (compatible with the notion that the sum yielded 'zero'). (2) Perception of head rotation in space. During vestibular stimulation, Ss' estimates showed the same non-ideal gain-vs.-frequency characteristics as described above for the trunk. Neck stimulation induced an illusion as if the head had been rotated in space. This neck contribution was such that, when it was combined with its vestibular counterpart during head rotation on stationary trunk, the perception became almost veridical. On closer inspection, however, this neck contribution was found to reflect the sum of two components; one was the non-ideal neck signal contributing to the perception of 'trunk in space', the other was an almost ideal neck signal of head-on-trunk rotation. (3) The results could be described by a simple model. In this model, the erroneous vestibular signal 'head in space' is primarily used to create an internal representation of 'trunk in space'.(ABSTRACT TRUNCATED AT 400 WORDS)

Head

Results of speech perception and speech production training for three prelingually deaf patients using a multiple-electrode cochlear implant.

Five studies were conducted to measure changes in the perception and production of selected speech targets, with training, in three prelingually deaf patients. The two adults and one adolescent were implanted with the Cochlear (Nucleus) multiple-electrode prosthesis. The studies were perception and production of nasal consonants; perception of syllable-final consonants; perception and production of alveolar consonants; auditory-visual perception of alveolar consonants; and perception and production of vowels. Perceptual data were collected in the audition (implant)-alone condition, except for the auditory-visual perception of alveolar consonants where the audition-alone, vision-alone, and auditory-visual conditions were used. Speech perception data in the audition-alone condition were also collected from four postlingually deaf adult implant patients, without training, to indicate differences between the two classes of patients. The three prelingually deaf patients generally showed some improvements in speech production. In perception, improvements were recorded only for individual patients in some studies. The performance of the adolescent was better than that of the two adults in all cases. The perceptual performance of the postlingually deaf patients was superior to that of the prelingually deaf patients in all cases.

Adolescent

Duplex perception: a comparison of monosyllables and slamming doors.

Duplex perception has been interpreted as revealing distinct systems for general auditory perception and speech perception. The systems yield distinct experiences of the same acoustic signal, the one conforming to the acoustic structure itself and the other to its source in vocal-tract activity. However, this interpretation has not been tested by examining whether duplex perception can be obtained for nonspeech sounds that are not plausibly perceived by a specialized system. In five experiments, we replicate some of the phenomena associated with duplex perception of speech using the sound of a slamming door. Similarities between subjects' responses to syllables and door sounds are striking enough to suggest that some conclusions in the speech literature should be tempered that (a) duplex perception is special to sounds for which there are perceptual modules and (b) duplex perception occurs because distinct systems have rendered different percepts of the same acoustic signal.

Adult

Associations of Illness Perception, Resignation Coping, and Social Support With Self-Regulatory Fatigue in Patients With Type 2 Diabetes: A Cross-Sectional Study.

AIMS: To examine the associations among illness perception, resignation coping, social support, and self-regulatory fatigue (SRF) in patients with Type 2 diabetes mellitus. The study specifically explores whether resignation coping and social support exhibit indirect associations with SRF in the context of illness perception. DESIGN: A cross-sectional study. METHODS: From November 2024 to October 2025, a convenience sample of 302 adult patients with T2DM was recruited from a tertiary general hospital in China. Participants completed validated instruments with established psychometric properties, namely the Brief Illness Perception Questionnaire, the Medical Coping Modes Questionnaire, the Perceived Social Support Scale, and the Self-Regulatory Fatigue Scale. Statistical analyses included Spearman correlation and serial mediation analysis using the PROCESS Macro (Model 6) with bias-corrected bootstrapping. RESULTS: SRF was positively correlated with negative illness perception (r&#x2009;=&#x2009;0.579, p&#x2009;<&#x2009;0.01) and resignation coping (r&#x2009;=&#x2009;0.612, p&#x2009;<&#x2009;0.01), and negatively correlated with social support (r&#x2009;=&#x2009;-0.598, p&#x2009;<&#x2009;0.01). Serial mediation analysis revealed that illness perception was associated with SRF through indirect pathways involving resignation coping and social support. Resignation coping and social support mediated the association between illness perception and self-regulatory fatigue, both individually and sequentially. CONCLUSIONS: Negative illness perception correlates with higher SRF. This observed correlation is additionally linked to indirect pathways involving resignation coping and lower social support. Collectively, these findings highlight a pattern of interrelated cognitive (illness perception), behavioural (resignation coping), and resource (social support) factors that are associated with self-regulatory fatigue in this cross-sectional study. IMPLICATIONS FOR THE PROFESSION: The findings offer a clear, evidence-based framework for nursing practice. They highlight the potential value of integrated assessment and intervention that simultaneously addresses patients' illness beliefs, maladaptive coping strategies, and social support systems, which are associated with lower SRF and better diabetes self-management. REPORTING METHOD: This study adheres to the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines for cross-sectional studies. PATIENT OR PUBLIC CONTRIBUTION: Patients participated solely as research participants by providing survey data. They were not involved in the study design, implementation, data analysis, interpretation, or manuscript preparation. All patients provided written informed consent prior to questionnaire completion.

Humans

Some thoughts on the perception of ultrasonics by man.

After a short specification of the ultrasonic transmitter device by which the test frequencies of 20,40,60 and 100 kHz could be emitted by means of a transmitter fixed to the forehead of the subject with constant pressure, the mean perception threshold for ultrasonics is described, which had been recorded by using the wide-band noise of the audiometer MA 30. Both curves do not differ considerably so that ultrasonic investigations can be carried out in the presence of working noise without producing wrong measurement results. A comparison of perception between ultrasonic frequencies and audio frequencies in the hearing range showed that ultrasonics produce, independent of the stimulation frequency, the same sensory impression as a sound at a frequency of about 12 or 13 kHz. Applying this method to hard of hearing subjects with noise induced hearing damages and deaf subjects had the following results: 1. Subjects with noise induced hearing damages very early have a raised perception threshold for ultrasonics. There was no correlation between the extent of the auditory threshold (the shift of the threshold) and the perception threshold of ultrasonics. 2. Deaf people almost without exception are not able to perceive ultrasonics. 3. With hard of hearing of the inner ear of different genesis ultrasonic perception is varying. There was no particular raise of the ultrasonic perception threshold with hereditary hard of hearing of the inner ear. 4. On the basis of the results the question is discussed in which section of the auditory system ultrasonic perception occurs. In the opinion of the authors the origin of perception might be in the organ of Corti itself. An unambiguous proof, however, could not be found so far. At present the procedure of investigation does not yet allow an application in practical diagnostics of ear specialists.

Adolescent

Anxiety induced by cardiac perceptions in patients with panic attacks: a field study.

In panic disorder bodily sensations appear to play an important role as a trigger for anxiety. In our psychophysiological model of panic attacks we postulate the following vicious circle: individuals with panic attacks perceive even quite small increases in heart rate and interpret these changes as being catastrophic. This elicits anxiety and a further increase in heart rate. To evaluate this model we conducted a field study of 28 subjects with panic attacks and 20 healthy controls. A 24 hr ambulatory ECG was recorded and the subjects were instructed to report any cardiac perceptions during this period and to rate the anxiety elicited by these perceptions. The incidence of cardiac perceptions was about the same in both groups, but only subjects with panic attacks reported anxiety associated with such perceptions. Analysis of the ECGs revealed that in both groups heart rate accelerations preceded cardiac perceptions. Following cardiac perceptions, the healthy controls showed a heart rate deceleration, whereas the subjects with panic attacks had a further acceleration. This heart rate increase after cardiac perceptions was positively related to the level of anxiety elicited by the perceptions. These results provide clear evidence in support of the vicious circle model of panic attacks.

Adult

Strengthening physical self-perceptions through exercise.

Two studies examined the effects of physical activity/exercise on physical self-perceptions, self-efficacy, body satisfaction, fitness and relationships among these variables. In study 1, 34 female undergraduates participated in a 10-week exercise/activity program. Participants were selected from existing classes forming a weight training, aerobic exercise and activity control group. Results revealed changes in physical self-perceptions, strength, and body composition over the 10-weeks. Improvements in physical self-perceptions and fitness occurred independent of exercise/activity group. Groups differed in the perceived importance attached to physical self-perceptions. Correlations among the measures revealed relationships among physical self-perceptions, body satisfaction, global self-esteem, and fitness. In study 2, we hypothesized that weight training would have a greater effect on physical self-perceptions and body image perceptions than physical education activity classes. Thirty-seven males and 28 females were selected from existing classes forming a weight training and activity group. Results revealed no significant changes in physical self-perceptions, body image, or global self-esteem over the 10-week program, while strength and physical self-efficacy improved. Correlations among measures from both studies offer preliminary support for Sonstroem and Morgan's model for the examination of self-esteem in exercise settings.

Adolescent

Perception of forearm angles in 3-dimensional space.

The purpose of this study was to determine a preferred coordinate system for representation of forearm orientation in 3-dimensional space. In one experiment, the ability of human subjects to perceive angles of the forearm in 3-dimensional space (forearm elevation and yaw--extrinsic coordinate system) was compared to their ability to perceive elbow joint angle (intrinsic coordinate system). While blindfolded, subjects performed an angle reproduction task in which the experimenter first positioned the upper limb in a reference trial. This was followed, after movement of the subject's entire upper limb to a different position, by an attempt to reproduce or match a criterior angle of the reference trial by motion of the forearm in elbow flexion or extension only. Note that matching of the criterion forearm angle in the new upper limb position could not be accomplished by reproducing the entire reference upper limb position, but only by angular motion at the elbow. Matching of all 3 criterion angles was accomplished with about equal accuracy in terms of absolute constant errors and variable errors. Correlation analysis of the perceptual errors showed that forearm elevation and elbow angle perception errors were not biased but that forearm yaw angle matching showed a bias toward elbow angle matching in 7 of 9 subjects. That is errors in forearm yaw perception were attributed to a tendency toward a preferred intrinsic coordinate system for perception of forearm orientation. These results show that subjects can accurately perceive angles in both extrinsic and intrinsic coordinate systems in 3-dimensional space. Thus, these data conflict with previous reports of highly inaccurate perception of elbow joint angles in comparison to perception of forearm elevation. In an attempt to resolve this conflict with previous results, a second experiment was carried out in which perception of forearm elevation and elbow joint angles with the forearm motion constrained to a vertical plane. Results of this experiment showed that during a two-limb elbow angle matching task, four of five subjects exhibited a clear bias toward forearm elevation angle. During a one-limb angle reproduction task only two of five subjects exhibited such a bias. Perception of elevation angles show little bias toward elbow angle matching.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult

Neural mechanisms of tactual form and texture perception.

In the last decade or so, there has been rapid movement toward the use of more complex stimuli in the study of perceptual function related to the hand. This review has focused on the neural mechanisms of form and texture perception. Evidence from neurophysiological and psychophysical studies in which static touch, scanning touch, and the Optacon were used indicate that the spatial acuity of the RA system may be as much as three times poorer than the SAI system, evidence that suggests that form perception is dominated by the SAI system. Pattern recognition behavior in a tactual letter recognition task appears to be directly related to the response properties of SAI afferent fibers. Psychophysical studies of roughness perception show that roughness magnitude is related to surface structure in an orderly manner. Because roughness varies along an intensive continuum, mean impulse rate in one or more of the afferent systems is the most obvious coding possibility. No satisfactory relationship between mean impulse rate and roughness has been observed, however. The strongest hypothesis is that tactual roughness perception is based on spatial variation in the SAI population response. The combined evidence from studies reviewed here suggests complementary roles for each of the afferent systems, which are presented as working hypotheses: The SAI system is the primary spatial system and is responsible for tactual form and roughness perception when the fingers contact a surface directly and for the perception of external events through the distribution of forces across the skin surface. The PC system is responsible for the perception of external events that are manifested through transmitted high-frequency vibrations of the kind that are critical in the use of objects as tools. The RA system is responsible for the detection and representation of localized movement between skin and a surface as well as for surface form and texture when surface variation is too small to activate the SAI afferents effectively.

Animals

Characterizing the influence of native language experience on adult speech perception.

Previous cross-language research has indicated that some speech contrasts present greater perceptual difficulty for adult non-native listeners than others do. It has been hypothesized that phonemic, phonetic, and acoustic factors contribute to this variability. Two experiments were conducted to evaluate systematically the role of phonemic status and phonetic familiarity in the perception of non-native speech contrasts and to test predictions derived from a model proposed by Best, McRoberts, and Sithole (1988). Experiment 1 showed that perception of an unfamiliar phonetic contrast was not less difficult for subjects who had experience with an analogous phonemic distinction in their native language than for subjects without such analogous experience. These results suggest that substantive phonetic experience influences the perception of non-native contrasts, and thus should contribute to a conceptualization of native language-processing skills. In Experiment 2, English listeners' perception of two related nonphonemic place contrasts was not consistently different as had been expected on the basis of phonetic familiarity. A clear order effect in the perceptual data suggests that interactions between different perceptual assimilation patterns or acoustic properties of the two contrasts, or interactions involving both of these factors, underlie the perception of the two contrasts in this experiment. It was concluded that both phonetic familiarity and acoustic factors are potentially important to the explanation of variability in perception of nonphonemic contrasts. The explanation of how linguistic experience shapes speech perception will require characterizing the relative contribution of these factors, as well as other factors, including individual differences and variables that influence a listener's orientation to speech stimuli.

Adolescent

[Perception of 2-dimensional space coordinates during prolonged experimental hypokinesia].

The effect of a 30-day hypokinesia on the perception of the subjective optic vertical (SOV) was studied. The test subjects who were in the antiorthostatic position (at an angle of 96 degrees to the vertical) showed the greatest changes in the SOV perception and illusive perception of the spatial position of the body. During the first two days of the experiment and ten days after it they displayed a 1.5-fold increase in the error of the SOV perception. In addition, they exhibited an asymmetrical perception of the SOV on the right and left side. In all cases the direction of the SOV displacement from the true line coincided with the body position. The test subjects who were kept at an angle of 84 degrees to the vertical (orthostatic hypokinesia) demonstrated only illusions of the body position during the first hypokinetic day and a unilateral increase in the error of the SOV perception after the experiment. The test subjects who underwent preventive treatment following antiorthostatic hypokinesia (at an angle of 94 degrees to the vertical) exhibited no asymmetry and an insignificant error in the SOV perception. These findings are discussed with regards to the changes in the function of pressuretension receptors and disorders in the skeletal tone during hypokinesia.

Adult

Suppression of cutaneous perception by magnetic pulse stimulation of the human brain.

We have demonstrated that magnetic pulse stimulation of the sensorimotor cortex suppresses perception of threshold electrical stimuli to the fingers of the contralateral hand. Maximum suppression of perception occurs when the fingers are stimulated 30-90 msec after the magnetic pulse. Thereafter, errors in perception of the cutaneous stimulus decrease to control levels by 300-400 msec after the magnetic pulse. The period of maximum suppression of perception coincides with the period during which cortically generated somatosensory evoked potentials (SEPs) are enhanced following magnetic pulse stimulation of the brain. The duration of suppression of perception, however, outlasts the duration of SEP enhancement. When the magnetic pulse is delivered after finger stimulation there is also suppression of perception. The suppression of perception is maximal when the magnetic pulse occurs 20-30 msec after finger stimulation. This interval coincides with the arrival of the afferent volley at the primary sensory cortex.

Electric Stimulation

[Perception of your body. A psychoanalytical approach].

This paper discusses body-perception from a psychoanalytic point of view. Ia attempts a "totalizing" view of human behavior which integrates the whole of perception-thought-action-perception as a single process of organism-environment interaction. The underlying episthemological framework implies the rejection of lineal causal deterministic explanations in favor of a dynamic conception, in terms of feed-back mechanisms. Thus it discards the various false oppositions between "body-perception" and "object-perception"; and between cognition, affectivity and connation. The former is resolved through the recognition of the fact that perception is always a comparative process, which results from the organism-environment interaction. The comparative element for body-perception is the dynamic unconsious body scheme. The latter opposition is resolved through the application of the basic psychoanalytic model, which integrates the primary models for cognition, affectivity and connation.

Body Image

Individual differences in the perception of bodily sensations: the role of trait anxiety and coping style.

Thirty young women participated in an experiment in which heart rate, blood pressure, respiration rate, skin conductance level and palmar sweat index were monitored at rest and during the administration of mental arithmetic, mirror drawing and cold pressor tasks. The accuracy of perception of somatic states was estimated by calculating within-subject correlations between four bodily sensations (racing heart, high blood pressure, shortness of breath and sweaty hands) and corresponding physiological parameters, assessed on eight occasions during the experiment. The accuracy of heart rate perception was highest, with a mean correlation between actual heart rate and ratings of racing heart of 0.76 and 66% of participants showing significant within-subject effects. The mean accuracy was 0.55 for systolic blood pressure, 0.48 for respiration rate, 0.47 for skin conductance level, and 0.64 for palmar sweat index. Accurate perception across physiological parameters did not cluster within individuals, and was not dependent on the range either of physiological changes or sensation ratings. Trait anxiety was not significantly associated with accuracy of somatic perception. Subjects with high trait anxiety reported larger increases in shortness of breath during tasks than did low anxious subjects, but this was not reflected in objective physiological measures. Information-seeking coping style, indexed by the monitoring scale of the Miller Behavioral Style Scale, was related to the accuracy of perception of skin conductance level and heart rate. The use of within-subject correlational strategies for assessing individual differences in perception of bodily states is discussed.

Adaptation, Psychological

A theory of visual interpolation in object perception.

We describe a new theory explaining the perception of partly occluded objects and illusory figures, from both static and kinematic information, in a unified framework. Three ideas guide our approach. First, perception of partly occluded objects, perception of illusory figures, and some other object perception phenomena derive from a single boundary interpolation process. These phenomena differ only in respects that are not part of the unit formation process, such as the depth placement of units formed. Second, unit formation from static and kinematic information can be treated in the same general framework. Third, spatial and spatiotemporal discontinuities in the boundaries of optically projected areas are fundamental to the unit formation process. Consistent with these ideas, we develop a detailed theory of unit formation that accounts for most cases of boundary perception in the absence of local physical specification. According to this theory, discontinuities in the first derivative of projected edges are initiating conditions for unit formation. A formal notion of relatability is defined, specifying which physically given edges leading into discontinuities can be connected to others by interpolated edges. Intuitively, relatability requires that two edges be connectable by a smooth, monotonic curve. The roots of the discontinuity and relatability notions in ecological constraints on object perception are discussed. Finally, we elaborate our approach by discussing related issues, some new phenomena, connections to other approaches, and issues for future research.

Attention

Interaction of vestibular and proprioceptive inputs for human self-motion perception.

Human perception of horizontal self(body)-motion in space was studied during various combinations of vestibular and leg-proprioceptive stimuli in the dark. During sinusoidal rotations of the trunk relative to the stationary feet (functionally synergistic combination) the perception was almost veridical over the frequency range tested (0.025-0.4 Hz). This finding suggested a dominance of the proprioceptive over the vestibular input, since the quantitative aspects of the perception (gain, phase, and detection threshold): (a) closely resembled those of the proprioceptive foot-to-trunk perception, and (b) clearly differed from those of the vestibular self-motion perception. However, when using other combinations, the self-motion perception changed in a monotonous way as a function of the two inputs, indicating that the two inputs do interact in a linear way. In a model of these findings the interaction occurs in two stages: (1) summation of a vestibular trunk-in-space signal and a (dynamically matched) proprioceptive foot-to-trunk signal yields an internal representation of foot support motion in space; (2) superposition of the latter by an almost ideal proprioceptive trunk-to-foot signal results in a representation of trunk-in-space motion (essentially proprioception-dependent and ideal when the feet are stationary).

Foot