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PubMedDate not supplied

[Engineering psychological principles of optimizing the control systems of flying vehicles].

Having reviewed literature publications and their own findings, the authors have formulated principles of optimization of control systems of flying vehicles which reflect certain psychophysiological patterns of human activity. Of greatest importance are the following principles: consistence of the information model to the operational image of the pilot and pattern of distribution of his attention; estimation of operational thresholds of signal perception; information integration into an integrally perceived image; selection of an optimal algorithm for the solution of flying and other problems; decrease of the load on the short-term and long-term memory. The authors have shown that the practical application of these principles requires a preliminary analysis of the psychophysiological structure of the activity of crewmembers.

Aircraft↗
PubMed1983

[Neuronal reactions of the fastigial nucleus in the cat to sound signals].

28 out of 67 neurones of the fastigial nucleus responded to sound signals in anesthetized cats. Thresholds of the responses were over 72 dB in most of the neurones. Changes in intensity or duration of the sound signals were followed by insignificant changes in neuronal activity. An insignificant frequency selectivity (Q less than 0.2) was found in 8 (29%) neurones out of the 28. A considerable sensitivity was revealed in respect to the signals simulating spatial location or moving of the sound source. 13 out of 16 neurones (81%) responded to changes in interaural differences of the stimulation in time. Half of these neurones revealed the maximal changes of activity in interaural differences lesser than 50 microseconds (i.e. with the delays simulating the situation of the sound source near the midline of the head). 7 out of 18 neurones (39%) proved to be sensitive to "movement" of the sound source, each neuron having a preferential sensitivity to the movement with a certain speed.

Acoustic Stimulation↗
PubMed1981

Aging and low-contrast vision: face perception.

Previous work showed that despite good visual acuity, many healthy older people require more contrast to see gratings of low and intermediate spatial frequencies than do younger observers. Here we report that a daily perceptual activity, which relies on lower spatial frequency information, is also adversely affected: as compared to young individuals, many older individuals require more contrast to detect a face and to discriminate between two faces. Ocular pathology, optical changes within the eyeball, and variation in criterion are ruled out as explanations for the age-related elevation in threshold.

Adult↗
PubMed1993

Egocenter location in children with strabismus: in the median plane and unchanged by surgery.

PURPOSE: Previous studies have shown that there are spatial localization shifts after horizontal strabismus surgery when a patient performs an open-loop pointing task. After monocular enucleation, an adult will also show a shift in the pointing response. Other studies have shown that in children who underwent enucleation, the egocenter location shifts toward the remaining eye. Is the pointing shift after surgery in children with strabismus the result of a shift in egocenter location? METHODS: Using a modified Roelofs' method for measuring the egocenter, eight children were tested before and after horizontal strabismus surgery to see if there were any shifts in egocenter location. One control group consisted of six children undergoing surgery for correction of vertical strabismus in which the horizontal muscles would be unaltered. RESULTS: Presurgery measurements of egocenter location in the people with strabismus were the same as those found in the other control group of 12 normal children. Postsurgical measurements of eye position showed horizontal rotations of 14.5 degrees for the horizontal group and 2.4 degrees for the vertical group. Egocenter measurements showed no postoperative shift for either strabismus group. CONCLUSIONS: Thus, the pointing shift seen in the previous studies is not from a shifting egocenter location but from a change in the registered position of the eye in the orbit.

Child↗
PubMedDate not supplied

Spatial orientation in aviation: visual contributions.

Misjudgment of spatial orientation is reported to be an important factor in a substantial proportion of aviation accidents. The likelihood of such misjudgment is particularly high when there are conflicting interactions between labyrinthine and visual signals. In a manoeuvering aircraft, visual information is often a crucial factor in the pilot's ability to judge the aircraft's altitude and position with respect to external and terrain features. A body of research evidence supports the following conceptual framework. (1) The human visual system processes a limited number of visual dimensions almost independently of each other (for example, colour, luminance, spatial frequency, orientation, changing size, motion in depth, time to contact). (2) Each of these selective sensitivities shows considerable intersubject variability. (3) Intersubject variability is far from perfectly correlated across the set of selective sensitivities. This paper discusses the relevance of this framework for predicting, first the specific situations in which visual judgments are most likely to occur and, second, which individual pilots are most likely to make the visual misjudgments.

Accidents, Aviation↗
PubMed1995

Perception of arm orientation in three-dimensional space.

The purpose of this investigation was to determine the preferred coordinate system for perception of arm (humerus) orientation in three-dimensional space. Perception of arm orientation relative to trunk-fixed versus earth-fixed axes were compared in seven human subjects. The experimenter first moved the subject's trunk and arm into a target configuration (in which the arm's orientation relative to the trunk and/or earth was perceived and memorized by the subject) and then moved the trunk and arm to a new configuration. The blindfolded subject then attempted to reproduce the target orientation of their arm relative to either the trunk (i.e., reproduce shoulder angles--intrinsic kinesthetic coordinate system) or earth-fixed axes (extrinsic kinesthetic coordinate system). Perceptual errors were similar for both shoulder (arm relative to trunk) and extrinsic (arm relative to earth) angles. However, elevation angles were perceived with greater accuracy than yaw angles in the two coordinate systems. Also, perceptual errors for arm yaw angles in the extrinsic kinesthetic coordinate system task were better predicted from changes in trunk orientation than the errors for other angles. Furthermore, four subjects matched arm yaw angle relative to the trunk-fixed axis more accurately than to the earth-fixed axis in the extrinsic coordinate system task. These results suggests a bias toward perception of yaw angles relative to trunk-fixed axes (i.e., in an intrinsic coordinate system). These data suggest that the preferred coordinate system for kinesthetic perception of arm orientation is probably fixed in the trunk.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Perceptual differences between vowels located in a limited phonetic space.

The perception of subphonemic differences between vowels was investigated using multidimensional scaling techniques. Three experiments were conducted with natural-sounding synthetic stimuli generated by linear predictive coding (LPC) formant synthesizers. In the first experiment, vowel sets near the pairs (i-I), (epsilon-ae), or (u-U) were synthesized containing 11 vowels each. Listeners judged the dissimilarities between all pairs of vowels within a set several times. These perceptual differences were mapped into distances between the vowels in an n-dimensional space using two-way multidimensional scaling. Results for each vowel set showed that the physical stimulus space, which was specified by the two parameters F1 and F2, was always mapped into a two-dimensional perceptual space. The best metric for modeling the perceptual distances was the Euclidean distance between F1 and F2 in barks. The second experiment investigated the perception of the same vowels from the first experiment, but embedded in a consonantal context. Following the same procedures as experiment 1, listeners' perception of the (bv) dissimilarities was not different from their perception of the isolated vowel dissimilarities. The third experiment investigated dissimilarity judgments for the three vowels (ae-alpha-lambda) located symmetrically in the F1 X F2 vowel space. While the perceptual space was again two dimensional, the influence of phonetic identity on vowel difference judgments was observed. Implications for determining metrics for subphonemic vowel differences using multidimensional scaling are discussed.

Adult↗
PubMed2003

A theory of magnitude: common cortical metrics of time, space and quantity.

Research into the perception of space, time and quantity has generated three separate literatures. That number can be represented spatially is, of course, well accepted and forms a basis for research into spatial aspects of numerical processing. Links between number and time or between space and time, on the other hand, are rarely discussed and the shared properties of all three systems have not been considered. I propose here that time, space and quantity are part of a generalized magnitude system. I outline A Theory Of Magnitude (ATOM) as a conceptually new framework within which to re-interpret the cortical processing of these elements of the environment.

Journal Article↗
PubMed1977

[Information transfer in the human perception of body position in space during lateral tilt (author's transl)].

(1) With eight human subjects, the perception of position in space during lateral tilt was studied by a method of absolute judgement. A preliminary analysis showed that each subject required 1000 stimuli, with 36 stimulus categories, to attain statisticach subject required 1000 stimuli, with 36 stimulus categories, to attain statistical significance. (2) Since it would be hard to experiment with such long durations, normalized experiments were pooled. The average information transfer was 3.0 bit/stimulus. (3) A closer look at the information transmission in various portions of the stimulus-response relationship (partial information transfer) revealed that near the vertical, with the head uppermost, there is more information transmission than in all other positions. This is in contrast to the visual perception of line orientation. (4) The stimulus-response relationship shows a small nonlinearity. Deviations of the body position from the vertical, with the head down, are underestimated up to 70 degrees away from the vertical; deviations from the vertical with the head uppermost are underestimated up to 10 degrees away from the vertical but overestimated up to 70 degrees.

Humans↗