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PubMed1990

Switching between memory and perception: moving attention or memory retrieval?

Weber, Burt, and Noll (1986) estimated that the time needed to switch attention between memory and perception was around 300 msec. The first two experiments in the present paper estimated switching time using a variation of their task. Subjects reported aloud lists of six items. The items were read off a computer screen (perception), recited from memory, or reported alternately from the two sources. The data show that the switching-time estimate is influenced by input/output compatibility, response-initiation times, and memory load. When these factors were controlled, estimated switching time dropped to around 100-150 msec. The data suggest, however, that the switch from perception to memory might be slower than the switch from memory to perception, which would invalidate the formula used to compute switching time. Experiment 3 tested the time for a single switch from perception to memory and a single switch from memory to perception by restricting report to one pair of items in the list. When the to-be-reported pair was precued, estimated switching time dropped to zero. When the pair was not precued, the memory-to-perception switching time remained at zero, but the perception-to-memory time was more than 400 msec. The pattern of results forced a reconceptualization of the task in terms of memory retrieval rather than attention switching. The attention-switching times appear to reflect processes required to select items from memory.

Adult↗

PubMed1989

The social bases of discrepancies in health/illness perceptions.

Health care professionals generally assume that their perceptions and assessments of their patients' health status are accurate and are congruent with those of the patient and other health care providers. However, despite the patient education process, there is evidence that discrepancies in perceptions persist. These discrepancies are of particular concern to nurses because they may interfere with the provision of quality patient care. Poor communication, non-compliance with the treatment regimen, inadequate or unnecessary treatment, and ethical problems could be outcomes of discrepancies in perceptions. In this paper, the literature pertaining to discrepancies in health/illness perceptions is reviewed. As well, several social factors that may affect perceptions are described. These include cultural background, gender, socioeconomic status, experience and role. The effect of occupational role on health/illness perceptions has not been examined systematically. Regarding differences in perceptions of physicians, nurses and patients, further research is required to clarify and explain the nature of discrepancies in health/illness perceptions.

Attitude of Health Personnel↗

PubMed1992

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↗

PubMed1990

A new version of duplex perception: evidence for phonetic and nonphonetic fusion.

In a series of experiments, a variant of duplex perception was investigated. In its original form, duplex perception is created by presenting an isolated transition to one ear and the remainder of the syllable, the standard base, to the other ear. Listeners hear a chirp at the ear receiving the isolated transition, and a full syllable at the ear receiving the base. The new version of duplex perception was created by presenting a third-formant transition in isolation to one ear and the same transition electronically mixed with the base to the other ear; the modified base now has all the information necessary for syllabic perception. With the new procedure, listeners reported hearing a chirp centered in the middle of their head and a syllable in the ear presented the modified base that was clearer than that produced by the isolated transition and standard base. They could also reliably choose the patterns that contained the additional transition in the base when attending to either the phonetic or nonphonetic sides of the duplex percept. In addition, when the fundamental frequency, onset time, and intensity of the isolated third-formant transition were varied relative to the base, the phonetic and nonphonetic (lateralization) percepts were differentially affected, although not always reliably. In general, nonphonetic fusion was more affected by large differences in these variables than was phonetic fusion. However, when two isolated third-formant transitions were presented dichotically, fusion and the resulting central location of the chirp failed markedly with relatively small differences in each variable. The results were discussed in terms of the role of fusion in the new version of duplex perception and the nature of the information that undergoes both phonetic and nonphonetic fusion.

Adult↗

PubMed1990

Physician behaviors, patient perceptions, and patient characteristics as predictors of satisfaction of hospitalized adult cancer patients.

To examine potential predictors of cancer patient satisfaction with physician behavior, 366 cases were studied. Physician behavior was measured on morning rounds using the Physician Behavior Check List (PBCL). Patient satisfaction and perceptions were assessed after the visit. Patient characteristics were obtained from the chart and the physician. Results showed wide variation in physician behavior; no "standard" set of behaviors was seen in all interactions. Patient satisfaction was high (mean = 87.8 mm on a 100-mm scale). Path analysis showed four variables predicted 62% of the variance in patient satisfaction. The strongest predictor was the patient perception item, "perception of needs addressed that day." Other predictors were perception of emotional support provided by the physician, age (older), and one physician behavior, "discusses treatment." Patient perceptions of needs met or emotional support provided were predicted by perceptions of the occurrence of physician behaviors involving information such as the diagnosis and tests and treatment. Overall, patient perceptions of physician behaviors were stronger predictors of patient satisfaction than the actual occurrence or absence of those behaviors.

Consumer Behavior↗

PubMed1991

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↗

PubMed1988

A mechanism for the direct perception of change: the example of bacterial chemotaxis.

The relationship between the behavior of single-celled organisms and cognition in higher animals is explored. Recent research and theory in bacterial chemotaxis are presented, together with a discussion of the implications of chemotaxis for perceptual theory. A number of parallels between chemotaxis and perception in higher organisms are drawn. It is suggested that Koshland's model of the chemical processes controlling chemotaxis is an example of a mechanism for direct perception of change and can help elucidate Runeson's work on 'smart mechanisms' of perception. It is argued, more generally, that the growing body of knowledge about the perceptual activities of lower organisms should be used to broaden the factual base on which theories of perception are constructed: eg explication of perceptual parallels between humans and lower organisms should help clarify the nature of these phenomena in humans and, perhaps, help in the development of theories of greater generality. Also, the debate between direct and indirect theories of perception may be advanced by analysis of the specific mechanisms used by lower organisms. Contrasts to mediated perception are pointed out and arguments for the relative simplicity and explanatory power of theories of direct perception are provided.

Animals↗

PubMed1989

Static, dynamic, and relational properties in vowel perception.

The present work reviews theories and empirical findings, including results from two new experiments, that bear on the perception of English vowels, with an emphasis on the comparison of data analytic "machine recognition" approaches with results from speech perception experiments. Two major sources of variability (viz., speaker differences and consonantal context effects) are addressed from the classical perspective of overlap between vowel categories in F1 x F2 space. Various approaches to the reduction of this overlap are evaluated. Two types of speaker normalization are considered. "Intrinsic" methods based on relationships among the steady-state properties (F0, F1, F2, and F3) within individual vowel tokens are contrasted with "extrinsic" methods, involving the relationships among the formant frequencies of the entire vowel system of a single speaker. Evidence from a new experiment supports Ainsworth's (1975) conclusion [W. Ainsworth, Auditory Analysis and Perception of Speech (Academic, London, 1975)] that both types of information have a role to play in perception. The effects of consonantal context on formant overlap are also considered. A new experiment is presented that extends Lindblom and Studdert-Kennedy's finding [B. Lindblom and M. Studdert-Kennedy, J. Acoust. Soc. Am. 43, 840-843 (1967)] of perceptual effects of consonantal context on vowel perception to /dVd/ and /bVb/ contexts. Finally, the role of vowel-inherent dynamic properties, including duration and diphthongization, is briefly reviewed. All of the above factors are shown to have reliable influences on vowel perception, although the relative weight of such effects and the circumstances that alter these weights remain far from clear. It is suggested that the design of more complex perceptual experiments, together with the development of quantitative pattern recognition models of human vowel perception, will be necessary to resolve these issues.

Humans↗

PubMed1992

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↗

PubMed1989

Phoneme perception via hearing aids with and without compression and the role of temporal resolution.

Hearing impairment is more than a sensitivity loss. The causes of reduced discrimination can be found also in deteriorations in loudness perception (recruitment), frequency resolution and temporal resolution. Only recruitment can be compensated for by modern hearing aids, namely by the reduction of the dynamic range by means of compression. However, the introduction of compression introduces temporal distortions, which may deteriorate the temporal cues of speech. In this study the perception of nonsense consonant-vowel-consonant-words presented through hearing aids was studied in a group of 12 hearing-impaired listeners. Phoneme perception in conditions with and without compression was analyzed and related to temporal parameters of the listeners' hearing. A detailed analysis of the patterns of confusions revealed clear qualitative differences in the perception of phonemes with and without compression. These differences can be related to an improved perception of temporal cues like the preburst silent interval of plosives and to spectral changes induced by the activation of the compression circuit. A reduced temporal resolution is disadvantageous for the perception of temporal cues like plosive detection, but our data do not suggest that the perception of temporal cues is hampered excessively by temporal distortions from the compression circuit itself.

Adolescent↗

PubMed1992

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↗

PubMedDate not supplied

[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↗

PubMed1990

[Disturbances of visual perception and the lesions on spastic diplegia].

In a study of 12 cerebral palsy with spastic diplegia, the relationship between their disturbances of visual perception and their lesions was discussed. All of them were performed Frostig Developmental Test of Visual perception and Tanaka-Binet Intelligence Test. Six of them showed disturbances of visual perception on Frostig Test. Subtest II, figure-ground, was the lowest of all subtests. The mean of perceptual quotient was under that of intelligence quotient significantly (p less than 0.05 t-test). MRI examination was performed to all and the lesions were detected at 10 of them. Six who showed disturbances of visual perception had the lesions and two who showed good visual perception had no lesions. The lesions were periventricular white matter and extended to semioval center and subcortical white matter at parietal and occipital lobes. Anatomically, their lesions correspond to superior longitudinal bundle and vertical occipital bundle and their bundles have important functions as the pass way of visual perception. Therefore, it was suggested that the disturbances of visual perception detected at spastic diplegia were based on the lesions and the mechanism was disconnection of higher visual pass way.

Brain↗

PubMed1992

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↗

PubMed1989

Benefit from admission to a geriatric assessment and rehabilitation unit. Discrepancy between health professional and client perception of improvement.

To determine differences in perception of benefit from a patient's admission to a geriatric Assessment and Rehabilitation Unit, we asked both medical and nursing staff (health team) and the patient and carer (clients) for their evaluation after discharge. The areas studied were functional ability, relief of the principal symptom, education about the principal problem, and development of coping skills. Of 94 patients studied, 58 patients were discharged to the community (52 to carers, 6 to live alone) and 36 to institutions. In the former group, the health team had a consistently higher perception of benefit than the clients (P less than .001). Factors positively predicting health team perception of benefit were a higher carer happiness, improvement in patient independence, and internalization of the patient's locus of control. A negative predictor was an increase in patients' responsibilities. Client perception of benefit was positively predicted by fewer problems with companionship and communication with others. The health team's perception rated the adequacy of patient education and development of coping skills more highly than did the clients. In the patients discharged to the community, their perception of benefit at 1 week was a good predictor of survival in the community to 6 weeks. The possible reasons for these differences in perception of benefit and their implications are discussed.

Activities of Daily Living↗

PubMed1990

Self-perceptions of first- and second-grade children with learning disabilities.

The present study addressed the question of the effects of developmental positive bias and repeated experiences of failure on the self-perception of mainstreamed first-and second-grade Israeli children with learning disabilities. The self-perceptions of 44 children with learning disabilities and their 36 nondisabled classmates were assessed. In addition, teachers' evaluations and objective measures of cognitive performance and social acceptance were gathered. The children with learning disabilities were found to have a greater positive bias and lower self-perception in the cognitive competence domain than their normally achieving peers. Self-perceptions of peer acceptance among children with learning disabilities are similar to their normally achieving peers' self-perceptions, in spite of their significantly lower sociometric ratings and teacher evaluations in the social domain. These findings are analyzed in the context of the globality-specificity dimension of self-perceptions at the age level studied. The obtained pattern of self-perceptions is discussed in the light of the interrelationships between cognitive deficit and experimental factors among mainstreamed first- and second-grade children.

Achievement↗

PubMed1978

[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↗

PubMed1989

Linear acceleration perception in the roll plane before and after unilateral vestibular neurectomy.

The ability of 33 patients to perceive the direction, relative to the body long axis, of a linear acceleration vector acting in the coronal plane, roll-tilt perception, was studied at various times, before and from 1 week to 6 months after unilateral, selective vestibular neurectomy for Meniere's disease, acoustic neuroma or intractable paroxysmal vertigo. The results of these patients were compared with the results of 31 normal subjects and two control patients who had both vestibular nerves surgically sectioned. Rotating on a fixed-chair centrifuge in an otherwise darkened room, each observer was required to indicate his perception of the direction of the resultant gravito-inertial vector by setting a small, motor-driven, illuminated bar, attached to the chair but rotatable in the fronto-parallel plane, to the perceived gravitational horizontal. Normal subjects accurately align the bar with respect to the gravito-inertial resultant vector which, in the dark, they assume to be the gravitational vertical. This percept has been called the oculogravic illusion. Accurate roll-tilt perception is due to vestibular (probably mainly otolithic) sensory information since patients with bilateral vestibular neurectomies do not perceive the resultant vector accurately. Whereas normal subjects perceive resultant vectors directed to the right and to the left equally accurately, roll-tilt perception was invariably asymmetrical one week after unilateral vestibular neurectomy. Even at rest there was an asymmetry in the baseline settings, so that patients set the bar down on the side of the operated ear, in order for it to appear gravitationally horizontal: if a patient had a right vestibular nerve section then he set the bar clockwise (from the patient's view) below the true gravitational horizontal. With increasing gravito-inertial resultant angles there was an increasing asymmetry of roll-tilt perception due both to decreased sensitivity to roll-tilt stimuli directed towards the operated ear and to transiently increased sensitivity to roll-tilt stimuli directed towards the intact ear. A progressive decrease in both perceptual asymmetries followed, rapidly in the first 3 weeks, more slowly in the next 6 months.(ABSTRACT TRUNCATED AT 400 WORDS)

Acceleration↗