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PubMed1997

Parallels between Perception without Attention and Perception without Awareness

Do studies of perception without awareness and studies of perception without attention address a similar underlying concept of awareness? To answer this question, we compared qualitative differences in performance across variations in stimulus quality (i.e., short vs. long prime-mask stimulus onset asynchrony) with qualitative differences in performance across variations in the direction of attention (i.e., focused vs. divided). The qualitative differences were based on three different phenomena: Stroop priming, false recognition, and exclusion failure. In all cases, variations in stimulus quality and variations in the direction of attention led to parallel findings. These results suggest that perception with and without awareness and perception with and without attention are equivalent ways of describing the same underlying process distinction.

Journal Article↗
PubMed2002

Heaviness perception. II. Contributions of object weight, haptic size, and density to the accurate perception of heaviness or lightness.

The present study investigated the contributions of object weight, haptic size, and density to the accurate perception of heaviness or lightness in the process of discriminating differences in weight between pairs of cubes with cue conflicts such as that resulting from the size-weight illusion. Fifteen subjects, with visual input blocked and relying on the input gained by grasping the cubes with only their fingertips, attempted to accurately discriminate possible differences in weight factor between the two respective cubes in each step of the trials. Three sets - one set each of copper (CP), aluminum (AL), and plastic (PL) - of seven cubes of various weight (0.10-0.74 N) were used. All of the cubes were covered with smooth, thin vinyl to eliminate possible input concerning density or material per se. Screens were strategically placed to eliminate any visual cues. One hundred and ninety-six trials with 37 combinations were pseudorandomly presented to subjects in the following conditions: PL versus AL, AL versus CP, and CP versus PL. Trials included 2 x 3 combinations on the basis of density (98 trials for higher and 98 for lower conditions) and weight (84 ascending trials for heavier, 28 for identical, and 84 descending for lighter conditions). The response for each trial given by each subject was regarded as correct when it accurately identified the weight relationship between the first and second cube. It was found that the subjects fairly accurately identified the weight relationship when density and weight both increased for the second cube (95.6% for given trials), and when density and weight both decreased (94.6%). The current results were markedly greater than those in the constant-density conditions obtained previously, suggesting that changes in density may be as much of an aid in the perception of heaviness and lightness as is weight. Whenever two cues conflicted directionally with each other, however, accuracy fell dramatically to 33.6% for lower density/ascending weight, and to 22.7% for higher density/descending weight. These results indicate the possibility of two different cues contributing to the perception of heaviness and lightness. Cue conflict such as the size-weight illusion naturally occurs when discriminating weight between objects. The present results, however, suggest that a person may perceive heaviness on the basis of the well-regulated relations between changes of density, size, and weight. The way in which these two cues are related through the haptic size is discussed.

Adolescent↗
PubMed1985

Perception of symmetry in infancy: the salience of vertical symmetry and the perception of pattern wholes.

Four experiments were conducted to assess converging aspects of 4-month-old infants' perception of symmetry in visual patterns. Experiments 1 and 2 manipulated the structure and orientation of comparable patterns in order to evaluate the specialty of vertical symmetry. Infants showed no preference among vertically symmetrical, vertically repeated, and obliquely symmetrical patterns, but they processed vertically symmetrical patterns more efficiently than either vertically repeated patterns or obliquely symmetrical patterns. Experiment 3 manipulated the spatial separation of pattern components in order to determine the ability of young infants to integrate and coalesce information in visual patterns that is distributed in space. Infants processed vertically symmetrical patterns whose components were contiguous or nearly contiguous about the vertical axis (0 to 2.5 degrees separations) more efficiently than discontiguous patterns (5 and 10 degrees separations). Thus, extreme spatial separation about the vertical meridian caused infants to lose the advantage for vertical symmetry, and by inference their holistic perception of the visual pattern. Experiment 4 manipulated the organization of individual components of a vertical pattern in order to examine further infants' sensitivity to perceptual organization and synthesis of pattern form. Infants discriminated vertically symmetrical patterns from asymmetrical patterns with a vertical organization, thereby demonstrating sensitivity to the symmetrical organization of the pattern above their perception of components in the pattern. The results of these four experiments together corroborate and extend previous findings that vertical symmetry has a special status in early perceptual development and that infants can perceive pattern wholes.

Female↗
PubMed1997

Visual motion perception after brain damage: I. Deficits in global motion perception.

We report on the test results of a group of 32 mostly unilaterally brain-damaged patients examined for global visual motion perception. Three of these patients had severely impaired visual motion perception in their contralateral visual half-field, a deficit remarkably similar to the perceptual defects found in V5-lesioned monkeys. Two of these three patients had a right-hemisphere lesion; the remaining one had a left-hemisphere lesion. We conclude that both hemispheres of the human brain contain an area, functionally equivalent to V5, which subserves visual motion perception in the contralateral visual half-field. Lesion analysis revealed that this area is located in the posterior medial temporal gyrus.

Adult↗
PubMed1992

Musical duplex perception: perception of figurally good chords with subliminal distinguishing tones.

In a variant of duplex perception with speech, phoneme perception is maintained when distinguishing components are presented below intensities required for separate detection, forming the basis for the claim that a phonetic module takes precedence over nonspeech processing. This finding is replicated with music chords (C major and minor) created by mixing a piano fifth with a sinusoidal distinguishing tone (E or E flat). Individual threshold intensities for detecting E or E flat in the context of the fixed piano tones are established. Chord discrimination thresholds defined by distinguishing tone intensity were determined. Experiment 2 verified masked detection thresholds and subliminal chord identification for experienced musicians. Accurate chord perception was maintained at distinguishing tone intensities nearly 20 dB below the threshold for separate detection. Speech and music findings are argued to demonstrate general perceptual principles.

Adult↗
PubMedDate not supplied

Perception of three-dimensional shape influences colour perception through mutual illumination.

Objects in the natural world possess different visual attributes, including shape, colour, surface texture and motion. Previous perceptual studies have assumed that the brain analyses the colour of a surface independently of its three-dimensional shape and viewing geometry, although there are neural connections between colour and two-dimensional form processing early in the visual pathway. Here we show that colour perception is strongly influenced by three-dimensional shape perception in a novel, chromatic version of the Mach Card--a concave folded card with one side made of magenta paper and the other of white paper. The light reflected from the magenta paper casts a pinkish glow on the white side. The perceived colour of the white side changes from pale pink to deep magenta when the perceived shape of the card flips from concave to convex. The effect demonstrates that the human visual system incorporates knowledge of mutual illumination-the physics of light reflection between surfaces--at an early stage in colour perception.

Brain↗
PubMed1985

The hostile media phenomenon: biased perception and perceptions of media bias in coverage of the Beirut massacre.

After viewing identical samples of major network television coverage of the Beirut massacre, both pro-Israeli and pro-Arab partisans rated these programs, and those responsible for them, as being biased against their side. This hostile media phenomenon appears to involve the operation of two separate mechanisms. First, partisans evaluated the fairness of the media's sample of facts and arguments differently: in light of their own divergent views about the objective merits of each side's case and their corresponding views about the nature of unbiased coverage. Second, partisans reported different perceptions and recollections about the program content itself; that is, each group reported more negative references to their side than positive ones, and each predicted that the coverage would sway nonpartisans in a hostile direction. Within both partisan groups, furthermore, greater knowledge of the crisis was associated with stronger perceptions of media bias. Charges of media bias, we concluded, may reflect more than self-serving attempts to secure preferential treatment. They may result from the operation of basic cognitive and perceptual mechanisms, mechanisms that should prove relevant to perceptions of fairness or objectivity in a wide range of mediation and negotiation contexts.

Hostility↗
PubMedDate not supplied

Speech sound representation, perception, and plasticity: a neurophysiologic perceptive.

Historically, auditory research has focused predominately upon how relatively simple acoustic signals are represented in the neuronal responses of the auditory periphery. However, in order to understand the neurophysiology underlying speech perception, the ultimate objective is to discover how speech sounds are represented in the central auditory system and to relate that representation to the perception of speech as a meaningful acoustic signal. This paper reviews three areas that pertain to the central auditory representation of speech: (1) the differences in neural representation of speech sounds at different levels of the auditory system; (2) the relation between the representation of sound in the auditory pathway and the perception/misperception of speech, and (3) the training-related plasticity of speech sound neural representation and speech perception.

Auditory Cortex↗
PubMed1976

Delusional perception and delusional notion linked to a perception.

It is a neglected psychopathological fact that Schneider clearly differentiated the delusional notion linked to a perception ("wahrnehmungsgebundener Wahneinfall") from the delusional perception ("Wahnwahrnehmung"). When this distinction is not taken into account, it is very likely that the probability of a false positive rating for the delusional perception is increased. A possible practical aid to help operationalize the differential "diagnosis" between these two symptoms is offered. The section on "delusional" phenomena in Wing's present-state examination is then discussed in the light of these distinctions.

Delusions↗
PubMed2004

Moderate alcohol consumption in humans impairs feature binding in visual perception but not across perception and action.

Animal studies suggest a relationship between activation of the cholinergic system and neural synchronization, which again has been suggested to mediate feature binding. We investigated whether suppressing cholinergic activity through moderate alcohol consumption in healthy humans affects behavioral measures of feature binding in visual perception and across perception and action. Indeed, evidence of the binding of shape and color, and of shape and location, of visual objects disappeared after alcohol consumption, whereas bindings between object features and the manual response were unaffected.

Adult↗
PubMed1990

Phantom auditory perception (tinnitus): mechanisms of generation and perception.

Phantom auditory perception--tinnitus--is a symptom of many pathologies. Although there are a number of theories postulating certain mechanisms of its generation, none have been proven yet. This paper analyses the phenomenon of tinnitus from the point of view of general neurophysiology. Existing theories and their extrapolation are presented, together with some new potential mechanisms of tinnitus generation, encompassing the involvement of calcium and calcium channels in cochlear function, with implications for malfunction and aging of the auditory and vestibular systems. It is hypothesized that most tinnitus results from the perception of abnormal activity, defined as activity which cannot be induced by any combination of external sounds. Moreover, it is hypothesized that signal recognition and classification circuits, working on holographic or neuronal network-like representation, are involved in the perception of tinnitus and are subject to plastic modification. Furthermore, it is proposed that all levels of the nervous system, to varying degrees, are involved in tinnitus manifestation. These concepts are used to unravel the inexplicable, unique features of tinnitus and its masking. Some clinical implications of these theories are suggested.

Humans↗
PubMed2001

Public perceptions of environmental quality: a survey study of beach use and perceptions in Los Angeles County.

Despite documented successes in the battle to clean up the coastal waters of Southern California, Los Angeles County residents continue to view the ocean more as a place of pollution than a vibrant and healthy place for bathing and swimming. This study shows that residents of Los Angeles County tend to hold perceptions of marine water quality that are at odds with data on bacteriological measures of water quality collected by local sanitation districts (and reported by not-for-profit Heal the Bay). Summary results of a survey of 400 randomly chosen households in Los Angeles County are given. Respondents were asked about their beach use and perceptions of environmental quality: both coastal water quality and air quality. The results suggest that perceptions of coastal water quality may be influenced less by "current coastal education campaigns" and more by the media and other factors.

Adult↗
PubMed1996

Patients' perception of quality hospital care and hospital occupancy: are there biases associated with assessing quality care based on patients' perceptions?

There currently is interest in evaluating medical outcomes based on patient perceptions. However, in the US there may be biases associated with these perceptions because of past marketing activities and other factors, such as facility location. The research question examined is whether perceived overall quality could predict hospital occupancy. To assess this, the quality ratings of 155 local hospitals by over 20,000 household heads surveyed in 20 US states were analyzed using an ecological research design. Facility image and hospital occupancy were assessed after controlling for community, facility and quality care differences between facilities. Results indicated that hospitals in more urbanized areas (p = 0.003), with lower costs (p = 0.0001), that were non-teaching (p = 0.033) and those with more employees per bed (p < 0.0001) had higher occupancies, but that perceived quality did not predict admissions after facility differences were controlled (p = 0.302). However, further analysis suggested both positive and negative biases may exist: controlling for community, facility, and quality care differences, facilities with "high" ratings appeared to have consistently higher occupancies, those with "low" ratings consistently lower occupancies, and facilities with "average" ratings appeared to be unaffected. Based on this finding, an interaction effect was tested and confirmed for community rating x facility size (p = 0.015), suggesting that smaller hospitals with low ratings had lower than expected occupancies. Although this study has limitations, it was suggested that researchers should use quality indicators based on patients' perceptions with caution and be open to additional scientific research, until these measures are better understood.

Bed Occupancy↗
PubMed2006

Psychophysically determined thresholds for thermal perception and pain perception in healthy women across the menstrual cycle.

OBJECTIVES: Several studies have indicated changes in sensation and/or pain sensitivity among women across the menstrual cycle, but the pattern of the changes varies considerably. One reason for the reported discrepancies could reside in lack of biochemical definition of menstrual cycle phase. The aim was to quantify temperature and temperature pain thresholds at biochemically defined stages of the menstrual cycle. METHODS: Nineteen healthy women were included in the study. Temperature and temperature pain thresholds were evaluated by quantitative sensory testing, performed at 3 occasions during the menstrual cycle (early follicular phase, late follicular phase, and mid-luteal phase). At each test session, serum concentrations of estradiol and progesterone were assessed. RESULTS: Thermal cold perception threshold at the mammilla was significantly lower in the late follicular and mid-luteal phases, compared with the early follicular phase (P<0.05, respectively). For the remaining test sites, no cycle related differences in thermal perception or thermal thresholds could be documented. CONCLUSIONS: The present study has indicated no major changes in thermal pain thresholds related to phase of the menstrual cycle for the tested locations, although thermal cold perception threshold at the mammilla was a significantly lower in the late follicular and mid-luteal phases, compared with the early follicular phase. The findings of the present study further underlines the need for strict criteria for menstrual cycle phase when studying pain sensitivity in relation to hormonal events in women.

Adult↗
PubMedDate not supplied

Development of adolescents' self-perceptions, values, and task perceptions according to gender and domain in 7th- through 11th-grade Australian students.

Latent growth models estimated developmental trajectories for adolescents' math and English self-perceptions (perceived talent, success expectancies), values (intrinsic, utility) and task perceptions (task difficulty, effort required). A longitudinal cohort-sequential study included 1,323 participants spanning Grades 7 to 11, with Occasion 1 mean ages 13.19, 12.36, and 14.41, respectively, for Cohorts 1, 2, and 3. Self-perceptions and values declined through adolescence, and ratings about difficulty and effort required increased. Gender differences favored boys for math and girls for English, with little evidence for gender intensification or gender convergence hypotheses. Explanations reference socialization and social-cognitive developmental theories and features of the curricula, with domain-specific patterns implying domain-specific explanations. Existing research is extended by modeling a broadened set of social-cognitive constructs within the Australian context.

Adolescent↗
PubMed2002

Relationships between maternal adult attachment security, child perceptions of maternal support, and maternal perceptions of child responses to sexual abuse.

This study assessed the relationships between maternal adult attachment style, children's perceptions of maternal support following disclosure of sexual abuse, and maternal perceptions of children's behavioral and emotional responses to sexual abuse among African-American child sexual abuse victims aged 4 to 12 (n=96) and a comparison group of non-abused subjects (n=100). Mothers with insecure attachment styles reported significantly higher rates of internalizing behaviors in their sexually abused children than did securely attached mothers. Among mothers of non-abused children, those with insecure adult attachment styles reported significantly higher rates of externalizing behaviors shown by their children in comparison with mothers with a secure adult attachment style. Mothers with insecure adult attachment styles also reported higher rates of overall behavior problems in their non-abused children that approached statistical significance. Sexually abused children's perceptions of maternal support were not related to maternal attachment style nor to child functioning. Contrary to our prediction, mothers of sexually abused children did not show lower rates of secure attachments when compared to mothers of non-sexually abused children. Our findings indicate that fostering parent- child attachment is important in order to decrease the risk for behavior problems and symptomatology in sexually abused children.

Adult↗
PubMed1987

Speech perception takes precedence over nonspeech perception.

Some components of a speech signal, when made more intense, are heard simultaneously as speech and nonspeech--a form of duplex perception. At lower intensities, the speech alone is heard. Such intensity-dependent duplexity implies the existence of a phonetic mode of perception that takes precedence over auditory modes.

Adult↗
PubMed2006

Limits of dynamic object perception in pigeons: dynamic stimulus presentation does not enhance perception and discrimination of complex shape.

A go/no-go procedure was used to train pigeons to discriminate pictures of human faces differing only in shape, with either static images or movies of human faces dynamically rotating in depth. On the basis of experimental findings in humans and some earlier studies on three-dimensional object perception in pigeons, we expected dynamic stimulus presentation to support the pigeon's perception of the complex morphology of a human face. However, the performance of the subjects presented with movies was either worse than (AVI format movies) or did not differ from (uncompressed dynamic presentation) that of the subjects trained with a single or with multiple static images of the faces. Furthermore, generalization tests to other presentation conditions and to novel static views revealed no promoting effect of dynamic training. Except for the subjects trained on multiple static views, performance dropped to chance level with views outside the training range. These results are in contrast to some prior reports from the literature, since they suggest that pigeons, unlike humans, have difficulty using the additional structural information provided by the dynamic presentation and integrating the multiple views into a three-dimensional object.

Animals↗