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PubMed1992

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↗

PubMed1991

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↗

PubMed1983

Role perception and role enactment of the nurse and their determinants in a teaching hospital in Nigeria.

This study was conducted to compare nurses' perception of their role with the perception which physicians and patients have of the role of nurses in a teaching hospital incorporating a school of nursing and midwifery; to explore the underlying reasons for the discrepancies found; to examine the effects of discrepancies in role perception on the effectiveness of patient care and to discuss the findings in the light of nursing education curricula in Nigeria. Questionnaires, listing ten technical/instrumental and expressive/humanitarian nursing functions were administered to three groups of respondents (nurses, physicians and patients). They were requested to select any five statements that best described what nurses did, and to rank them according to how often the functions described were seen being practised. A second questionnaire, administered only to the nurse respondents, elicited a number of background parameters related to nursing career. The results from the first questionnaire show that nurses did not seem to agree with patients and physicians on the perception and enactment of their role. Nurses saw their role as equally technical/instrumental and expressive/humanitarian, whereas patients and physicians saw it as more expressive/humanitarian, the patients being particularly more inclined to this perception. Most significant was the disagreement between patients and nurses. Nurses whose perception of their role agreed most closely with that of physicians and patients, were found to be older, and to have had longer experience. A significant proportion of them had only basic nursing qualifications, and they perceived their functions to be more appreciated by patients.

Adult↗

PubMed1992

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↗

PubMed1996

Object motion perception during ego-motion: patients with a complete loss of vestibular function vs. normals.

Object motion perception was assessed in avestibular patients and normal controls. Two experiments were conducted, in which subjects were required to assess the motion of a visual stimulus with respect to earth. In the first experiment, we measured the velocity at which a briefly presented (200 ms) grating was perceived as earth fixed, while the subject maintained fixation on a visual target fixed relative to the body, during whole-body yaw rotation (VOR suppression). In this experimental setup, the influence of the semicircular canal signals on object motion perception was evaluated. The avestibular patients judged the grating to be stationary with respect to earth, when it was moving at the same velocity as their body, whereas for normal controls, the grating was perceived as stationary when it moved at a velocity slower than their body motion, but greater than zero. The difference between the two subject groups was significant, and showed the strong contribution of the vestibular system to object motion perception. Similarly, a measurement of the velocity at which a grating was perceived as stationary was obtained during smooth pursuit eye movements. In this experiment the contribution of the efference copy of the oculomotor signal and proprioceptive signals to object motion perception were assessed. As with the first experiment, the normal controls displayed a more veridical sense of object motion perception than the patients, although the difference was only just significant. We suggest that the difference could be an adaptive change in the patients perception of motion, which allows them to reduce the effects of oscillopsia.

Humans↗

PubMed2006

Risk perception and impulsivity: association with risky behaviors and substance abuse disorders.

Low risk perception and high impulsivity, in conjunction with substance abuse disorders, are associated with the occurrence of injury in the general population. The study described in this article investigated the association of risk perception and impulsivity with risky behaviors (infrequent seat belt use, drinking and driving, riding with a drunk driver, binge drinking, and speeding for the thrill) among adults with unintentional blunt trauma. Patients (N = 756) were assessed for substance abuse disorders and participation in risky behaviors. Risk perception and impulsivity were measured by questionnaire. Pearson's chi-square statistic was used to investigate risk perception, impulsivity, substance abuse, and possible confounders relative to risky behaviors. Odds ratios were calculated using logistic regression methodology. Univariate results indicated that low risk perception and high impulsivity were significant risk factors for risky behaviors. After adjustment for confounding factors, low risk perception and high impulsivity remained significantly associated with risky behaviors in the trauma patient population.

Accidents, Traffic↗

PubMed2005

Categorical perception of speech sounds in illiterate adults.

Children affected by dyslexia exhibit a deficit in the categorical perception of speech sounds, characterized by both poorer discrimination of between-category differences and by better discrimination of within-category differences, compared to normal readers. These categorical perception anomalies might be at the origin of dyslexia, by hampering the set up of grapheme-phoneme correspondences, but they might also be the consequence of poor reading skills, as literacy probably contributes to stabilizing phonological categories. The aim of the present study was to investigate this issue by comparing categorical perception performances of illiterate and literate people. Identification and discrimination responses were collected for a /ba-da/ synthetic place-of-articulation continuum and between-group differences in both categorical perception and in the precision of the categorical boundary were examined. The results showed that illiterate vs. literate people did not differ in categorical perception, thereby suggesting that the categorical perception anomalies displayed by dyslexics are indeed a cause rather than a consequence of their reading problems. However, illiterate people displayed a less precise categorical boundary and a stronger lexical bias, both also associated with dyslexia, which might, therefore, be a specific consequence of written language deprivation or impairment.

Adolescent↗

PubMed2004

Perception of disease severity in adolescents diagnosed with neurofibromatosis type 1.

PURPOSE: To examine the relationship between adolescents' families' perception of the severity of neurofibromatosis (NF1) and the clinical severity of NF1, a genetic condition with variable manifestations. METHODS: The Perception of Severity of Chronic Illness (PSCI) questionnaire was administered to 56 parents of 47 adolescents with NF1. Each participant was asked one open-ended question regarding the challenges of living with NF1. Scores assessing the clinical severity of NF1 were assigned by health care providers in the NF Clinic. Correlation coefficients and paired t-test were used to evaluate the relationship between the clinical severity and the families' perceptions. Qualitative data were reviewed and grouped into themes. RESULTS: Parental perceptions were correlated with the degree of medical (r = 0.3116, p <.05), cognitive (r = 0.4911, p <.0001), and behavioral (r = 0.3341, p <.05) impairment of the adolescent. Adolescent perception was correlated with the degree of cognitive impairment (r = 0.5429, p <.0001). Parental and adolescent perceptions were correlated (r = 0.6724, p <.0001); however, adolescents viewed the condition's impact as being less than their parents (p <.001). The qualitative data provide additional insight into the concerns of these families. CONCLUSIONS: Families dealing with more medical, cognitive, and behavioral complications of NF1 perceive the impact of the condition on daily life as being greater than those families with fewer complications. The quantitative and qualitative results of this study have several implications for the clinical care of adolescents with NF1 and their families.

Adolescent↗

PubMed2004

Color term knowledge does not affect categorical perception of color in toddlers.

Categorical perception of color is shown when colors from the same category are discriminated less easily than equivalently spaced colors that cross a category boundary. The current experiments tested various models of categorical perception. Experiment 1 tested for categorical responding in 2- to 4-year-olds, the age range for the onset establishment of color term knowledge. Experiment 2 tested for categorical responding in Himba toddlers, whose language segments the color space differently from the way in which the English language does so. Experiment 3 manipulated the conditions of the task to explore whether the categorical responding in Experiments 1 and 2 was equivalent to categorical perception. Categorical perception was shown irrespective of naming and was not stronger in those children with more developed color term knowledge. Cross-cultural differences in the extent of categorical perception were not found. These findings support universalistic models of color categorization and suggest that color term knowledge does not modify categorical perception, at least during the early stages of childhood.

Child Language↗

PubMed2026

The impact of routine traffic encounters that include procedural justice on police perceptions.

OBJECTIVES: Despite procedural justice in police-citizen interactions being widely studied, there is limited research regarding police perceptions of these interactions. This study addresses this by exploring police perceptions of two different types of random breath test (RBT) - standard and procedurally just - in an experimental trial. Officers were asked to report on whether they believe that their RBT interaction with drivers and riders changed behaviour, developed more positive perceptions of police and resulted in slower travel. Additionally, they were asked if they thought that the RBT interaction took too long. METHODS: This study was a six month randomised control trial with two operational conditions: a control condition with a standard (n = 18 days) and an experimental condition with a procedurally just (n = 17 days) RBT. Police officers completed post-operation surveys (n = 80). RESULTS: Police officers incorporating the principles of procedural justice into RBT had limited impact on officer perceptions. However, those officers who were more open to innovation believed that the interaction would result in more positive perceptions of police. Police officers who believed that their RBTs with motorcycle riders would make a difference perceived that the riders would both change their behaviour and travel more slowly after the interaction. There were no differences in perceived interaction length by police officers across both conditions. CONCLUSIONS: This study has shown that police officer openness to innovation has an important role to play in police officers having more positive perceptions regarding the outcomes of RBT interactions. As such police organisations should undertake activities, such as training, to improve innovation. The lack of perceived differences in RBT length between standard and procedurally just interactions suggests that these enhanced interactions can be implemented without concerns that police officers believe that they 'take too long'.

Humans↗

PubMed2004

Improvement of fMRI data processing of olfactory responses with a perception-based template.

Neuroimaging and in particular functional magnetic resonance imaging (fMRI) of olfactory function relies on the ability to model the time course of brain responses elicited by odor stimuli. In this study we compared two templates of olfactory brain activation by comparing levels of correlation in regions critical to olfactory processing with either a stimulation-based template or a perception-based template, derived from perception profiles acquired off-line during a simulated fMRI session. fMRI signal was more correlated with the perception-based template than with the stimulation-based template in all regions. This effect was not observed when comparing correlations obtained with the exact same templates shifted in time by 12 s. Therefore, the improvement due to the use of the perception-based template was not only caused by a difference of shape between the stimulation-based and the perception-based template but was specifically related to the olfactory stimulation performed. These results suggest that the perception-based template better represents brain activity in response to olfactory stimulation and might help improve data processing of fMRI studies investigating olfactory function.

Adult↗

PubMed2005

Early computational processing in binocular vision and depth perception.

Stereoscopic depth perception is a fascinating ability in its own right and also a useful model of perception. In recent years, considerable progress has been made in understanding the early cortical circuitry underlying this ability. Inputs from left and right eyes are first combined in primary visual cortex (V1), where many cells are tuned for binocular disparity. Although the observation of disparity tuning in V1, combined with psychophysical evidence that stereopsis must occur early in visual processing, led to initial suggestions that V1 was the neural correlate of stereoscopic depth perception, more recent work indicates that this must occur in higher visual areas. The firing of cells in V1 appears to depend relatively simply on the visual stimuli within local receptive fields in each retina, whereas the perception of depth reflects global properties of the stimulus. However, V1 neurons appear to be specialized in a number of respects to encode ecologically relevant binocular disparities. This suggests that they carry out essential pre-processing underlying stereoscopic depth perception in higher areas. This article reviews recent progress in developing accurate models of the computations carried out by these neurons. We seem close to achieving a mathematical description of the initial stages of the brain's stereo algorithm. This is important in itself--for instance, it may enable improved stereopsis in computer vision--and paves the way for a full understanding of how depth perception arises.

Animals↗

PubMed2005

Is depth perception of stereo plaids predicted by intersection of constraints, vector average or second-order feature?

Stereo plaid stimuli were created to investigate whether depth perception is determined by an intersection of constraints (IOC) or vector average (VA) operation on the Fourier components, or by the second-order (non-Fourier) feature in a pattern. We first created stereo plaid stimuli where IOC predicted vertical disparity, VA predicted positive diagonal disparity and the second-order feature predicted negative diagonal disparity. In a depth discrimination task, observers indicated whether they perceived the pattern as 'near' or 'far' relative to a zero-disparity aperture. Observers' perception was consistent with the disparity predicted by VA, indicating its dominance over IOC and the second-order feature in this condition. Additional stimuli in which VA predicted vertical disparity were created to investigate whether VA would dominate perception when it was a less reliable cue. In this case, observers' performance was consistent with disparity predicted by IOC or the second-order feature, not VA. Finally, in order to determine whether the second-order feature contributes to depth perception, stimuli were created where IOC and VA predicted positive horizontal disparity while the second-order feature predicted negative horizontal disparity. When the component gratings were oriented near horizontal (+/-83 degrees from vertical), depth perception corresponded to that predicted by the second-order feature. However, as the components moved away from horizontal (+/-75 degrees and +/-65 degrees from vertical), depth perception was increasingly likely to be predicted by an IOC or VA operation. These experiments suggest that the visual system does not rely exclusively on a single method for computing pattern disparity. Instead, it favours the most reliable method for a given condition.

Contrast Sensitivity↗

PubMed2005

Eccentric perception of biological motion is unscalably poor.

Accurately perceiving the activities of other people is a crucially important social skill of obvious survival value. Human vision is equipped with highly sensitive mechanisms for recognizing activities performed by others [Johansson, G. (1973). Visual perception of biological motion and a model for its analysis. Perception and Psychophysics, 14, 201; Johansson, G. (1976). Spatio-temporal differentiation and integration in visual motion perception: An experimental and theoretical analysis of calculus-like functions in visual data processing. Psychological Research, 38, 379]. One putative functional role of biological motion perception is to register the presence of biological events anywhere within the visual field, not just within central vision. To assess the salience of biological motion throughout the visual field, we compared the detectability performances of biological motion animations imaged in central vision and in peripheral vision. To compensate for the poorer spatial resolution within the periphery, we spatially magnified the motion tokens defining biological motion. Normal and scrambled biological motion sequences were embedded in motion noise and presented in two successively viewed intervals on each trial (2AFC). Subjects indicated which of the two intervals contained normal biological motion. A staircase procedure varied the number of noise dots to produce a criterion level of discrimination performance. For both foveal and peripheral viewing, performance increased but saturated with stimulus size. Foveal and peripheral performance could not be equated by any magnitude of size scaling. Moreover, the inversion effect--superiority of upright over inverted biological motion [Sumi, S. (1984). Upside-down presentation of the Johansson moving light-spot pattern. Perception, 13, 283]--was found only when animations were viewed within the central visual field. Evidently the neural resource responsible for biological motion perception are embodied within neural mechanisms focused on central vision.

Discrimination, Psychological↗

PubMed1999

Older persons' perceptions of home and hospital as sites of treatment for acute illness.

PURPOSE: Home care is increasingly being used as a substitute for hospital care. This study examined older patients' perceptions of the home and of the hospital as treatment sites for acute illness and the patient characteristics that are associated with these perceptions. SUBJECTS AND METHODS: A series of questions derived from open-ended interviews supplemented by literature review were administered by telephone in a cross-sectional, descriptive study to community-dwelling persons age 65 years or older who had been hospitalized 2 months earlier with congestive heart failure, chronic obstructive pulmonary disease, or pneumonia. RESULTS: Among 246 participants, nearly equal proportions agreed with statements that the home and the hospital would be comfortable sites of care (54% versus 55%), that the home and the hospital would provide rapid recovery (41% versus 37%), and that home treatment and hospital treatment would be burdensome on family and friends (40% versus 33%). Although 93% would feel safe in the hospital, only 42% would feel safe at home. Perceptions were not associated with sociodemographic characteristics, primary diagnosis, self-rated health, depression, or social support. Functionally dependent patients had more positive perceptions of treatment at home. CONCLUSIONS: Evaluation of perceptions of home and hospital can facilitate assessing the acceptability of shifting acute care from hospital to home. Our findings suggest that successful expansion of acute home care will require flexibility in the use of home and hospital as well as education to change perceptions about the safety and efficacy of treatment at home.

Acute Disease↗

PubMed2002

The relationship between employees' perceptions of safety and organizational culture.

PROBLEM: With limited resources to help reduce occupational injuries, companies struggle with how to best focus these resources to achieve the greatest reduction in injuries for the optimal cost. Safety culture has been identified as a critical factor that sets the tone for importance of safety within an organization. METHOD: An employee safety perception survey was conducted, and injury data were collected over a 45-month period from a large ready-mix concrete producer located in the southwest region of the United States. RESULTS: The results of this preliminary study suggest that the reductions in injuries experienced at the company locations was strongly impacted by the positive employee perceptions on several key factors. Management's commitment to safety was the factor with the greatest positive perception by employees taking the survey. DISCUSSION: This study was set up as a pilot project and did not unitize an experimental design. That weakness reduces the strength of these findings but adds to the importance of expanding the pilot project with an appropriate experimental design. SUMMARY: Management leadership has been identified, along with several other factors, to influence employee perceptions of the safety management system. Those perceptions, in turn, appear to influence employee decisions that relate to at-risk behaviors and decisions on the job. IMPACT ON INDUSTRY: The results suggest that employee perceptions of the safety system are related to management's commitment to safety, which, in turn, appear to be related to injury rates. Management should focus on how to best leverage these key factors to more positively impact injury rates within their companies.

Attitude to Health↗

PubMed2000

The abused child as parent: the structure and content of physically abused mothers' perceptions of their babies.

OBJECTIVE: The major aim of the study was to provide an empirical answer to the following question: Does a mother's history of being physically abused as a child have a discernible impact on the structure and content of her perceptions and beliefs concerning her own child? METHOD: Free-response memories and current descriptions of babies, self, and significant others such as parents were compared longitudinally in two groups of mothers when their babies were 6 months, 1 year, and 2 years old. One group of mothers consisted of individuals who reported being physically abused as children; the control group consisted of mothers who were not physically abused. The two groups were comparable with respect to age of baby, race, and socioeconomic status. RESULTS: Abused mothers were found to differ significantly from control mothers in the structure and content of their free-response perceptions of their own babies. More specifically, abused mothers lagged behind controls in how well-differentiated were their negative perceptions of their babies. Differentiation in this study is operationally defined as the number of unique clusters that underlie a mother's perceptions of her baby, when social perception data is analyzed using cluster analysis (HICLAS). The greater the number of clusters observed, the greater is the differentiation. On the other hand, abused mothers were comparable to controls with respect to differentiation of positive perceptions of babies. CONCLUSIONS: The findings constitute a discovery about the structural organization of social cognition in mothers at-risk for child abuse. Implications of the findings for theory and future research are briefly discussed, as are limitations of the current study.

Adult↗

PubMed2002

Cantonese tone perception ability of cochlear implant children in comparison with normal-hearing children.

BACKGROUND AND OBJECTIVE: Cantonese is a tone language. A change in the fundamental frequency pattern within the same phonemic segment causes a change in the lexical meaning. The present study examined the Cantonese tone perception ability of cochlear implant children in comparison with normal-hearing children. It was hypothesized that cochlear implant children follow a similar pattern of tone perception development, as do normal children. METHOD: 225 normal-hearing and 15 hearing-impaired children with cochlear implants were recruited. The high level (tone 1), high rising (tone 2) and low falling (tone 4) were the target tones examined. The three tones were arranged into tone pairs for identification. Each pair shared exactly the same segmental information but differed only in tones (e.g. /sy/ in tones 1 and 2 meaning 'book' and 'mouse', respectively). Subjects were required to point to the corresponding pictures after the live voice presentations. RESULTS: for each tone pair, each subject was awarded a score representing the proportion of stimuli pairs that were correctly discriminated by the subject. The average scores in the normal-hearing and hearing-impaired groups were 0.92 and 0.64, respectively. The normal group had the lowest average score in tone 2/tone 4 (0.87) while the hearing-impaired group performed the worst in tone 1/tone 2 (0.53) perception between the three tone contrasts. CONCLUSIONS: the normal-hearing group performed significantly better than the hearing-impaired group in basic Cantonese tone perception. The pattern of tone perception development of cochlear implant children did not seem to follow that of normal children. Contributing factors on the tone perception performance of the cochlear implant children were subject's age, duration of special training, and durations of wearing the hearing aid and the cochlear implant.

Audiometry, Pure-Tone↗