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Biomedical subjects

S Coren

Publications and source records attributed to S Coren.

At least 55 records · Page 3Linked to original sources
PubMed1991

Retinal mechanisms in the perception of subjective contours: the contribution of lateral inhibition.

One mechanism frequently proposed for the creation of subjective contours and their related brightness effects involves lateral neural interactions on the retina, such as the lateral inhibitory effects that underlie brightness contrast. Subjective contour stimuli were displayed under an intermittent light source, with rapid onset and slow offset as has been shown to increase lateral inhibitory interactions by allowing summation of neural onset transients. A sample of forty subjects, using magnitude estimates, reported increased subjective contour clarity and brightness effects under these exposure conditions. The effects were larger for relative brightness differences than for contour visibility. It appears that this technique may have applications in exploring retinal contributions to other aspects of the perception of subjective contours.

Adult↗
PubMed1990

Moon illusion in pictures: a multimechanism approach.

The existence of the moon illusion in pictorial representations was demonstrated in 6 experiments. Ss either judged the size of the moon in pictures, depicted as on the horizon or high in the sky, or drew horizon and elevated moons. The horizon moon was consistently judged to be larger than the elevated moon, independent of the angle at which the pictures are viewed. The distance paradox usually observed with the moon illusion (horizon moon apparently closer than the elevated moon) also exists in pictures. The magnitude of both size and distance effects depends on the salience of depicted depth cues. The pattern of results suggests that the moon illusion is caused by several interacting mechanisms and that use of pictorial stimuli may allow the separation of various cognitive from physiological contributions to the illusion.

Attention↗
PubMed1990

Conversion between systems of hearing handicap measurement: an empirically determined computational procedure.

Audiograms collected from 821 individuals were used to determine the interrelationships among five systems of determining hearing handicap based upon pure-tone thresholds. These were the American Academy of Ophthalmology and Otolaryngology, the British Association of Otolaryngologists and the British Society of Audiology, the American Medical Association, the industrial, and the full-range averages. A high degree of correlation (average r = .981) was found among the various indices. Using the regressions between all possible pairs of indices, we constructed a table that allows conversion between the various systems involving only very simple computation.

Adolescent↗
PubMed1990

Methodological implications of interaural correlation: count heads not ears.

In a sample of 425 subjects, pure-tone hearing thresholds between the right and left ears were shown to have an average correlation of .885 (or .783 with age partialed out). This high interaural correlation is shown to invalidate the experimental procedure of entering data on the basis of "ears," where each subject can contribute one or two audiograms to the data pool, since such aggregation is demonstrated to produce spuriously high levels of apparent statistical significance in inferential statistical tests.

Adult↗
PubMed1989

Relationship between birth order, birth stress, and lateral preferences: a critical review.

Reviews the literature examining the relationship between birth order, birth stress, and lateral preferences in nonclinical samples, with special emphasis on reports since 1971. The review found no evidence to relate birth order position to deviations from right-sidedness for either sex. More direct measures of birth stress indicated that deviations from right-handedness (particularly for male subjects), and also right-eyedness, were statistically related to specific birth stressors. It should be stressed, however, that all the relationships, including the significant ones, were very weak, accounting for less than 1% of the variance. When statistical significance was achieved, it was largely due to the huge sample sizes used in the meta-analyses. Methological and theoretical problems exist in the current literature, and we offer some suggestions to resolve them.

Birth Order↗
PubMed1989

Validation of a self-report inventory for the measurement of visual acuity.

Previous attempts to assess visual acuity via self-report survey items have shown low sensitivity. This may be due to use of dichotomous response formats, too few items, and reliance upon face valid, rather than laboratory-validated items. On the basis of a preliminary sample of 164 individuals, we developed a self-report inventory, suitable for group testing or survey administration. The inventory was then validated against laboratory measures of acuity in a separate sample of 570 subjects. The resulting, brief, ten-item scale was shown to be a reliable and valid predictor of visual acuity. Conversion tables were developed which allow scale totals to be used to predict Snellen acuity. For 91% of the sample, the inventory predicts objectively measured acuity within plus or minus one Snellen line. A copy of the inventory and scoring procedure is appended to this report.

Humans↗
PubMed1989

Central and peripheral sensitivity to temporally modulated stimuli presented to the sighting and nonsighting eyes.

Thirty-two visually normal observers showed reduced sensitivity to uniform field flicker in the fovea of the nonsighting eye relative to the sighting eye. The two eyes showed equal sensitivity to flicker in the peripheral retina. This result with visually normal observers is analogous to that found in observers with functional amblyopia. It is also consistent with the hypothesis that amblyopic and normal suppressive processes share a common mechanism.

Contrast Sensitivity↗
PubMed1989

Left-handedness and accident-related injury risk.

Self-reported injuries among left-handed and right-handed people were compared in a survey of 1,896 college students in British Columbia, Canada. Left-handers were more likely to report having an injury requiring medical attention during the last two years (OR = 1.89, 95% CI = 1.39, 2.58). Relative risk was highest for left-handed males when driving motor vehicles (OR = 2.35, CI = 1.25, 4.43). Regardless of handedness, males had slightly higher relative risks of injury than females.

Accidents↗
PubMed1987

Left sidedness and sleep difficulty: the alinormal syndrome.

Four indexes of laterality: handedness, footedness, eyedness, and earedness, were assessed in a sample of 1274 subjects. Left- and right-sided groups were compared on two aspects of self-reported sleep difficulty: trouble falling asleep and frequent night wakenings. The incidence of sleep difficulty was found to be elevated in the left-sided groups. The results are discussed in terms of a possible complex of behavioral deviations from the statistical norm, called the alinormal syndrome.

Adult↗
PubMed1987

Reporting the visual acuity of groups: the relation among alternate measures.

There are often large disparities in the way in which visual acuities are reported for groups. A survey of 156 reports published within the last 5 years shows that some researchers report binocular acuity, others best eye, monocular, or mean monocular acuities. Some of these measures may be confounded further with accommodation distance. To ascertain the relation among the various measures of acuity reported commonly, data were obtained from 702 observers. The results indicate that there is a high degree of concordance among the various measures used to report the visual acuity of groups, with many of the correlations in the 0.9 range. It is further shown that a composite measure, based upon mean binocular or best eye acuity, may be a useful means of conveying group differences in visual resolution.

Adolescent↗
PubMed1987

A rapid method to assess crystalline lens pigment density in vivo.

A procedure for rapidly estimating lens pigment density, based upon metameric matches on the D & H Color Rule, is described. A computational nomograph to convert settings to lens densities is provided. This procedure was validated in a sample 126 normal observers, and shown to produce data comparable to more complex laboratory testing procedures. The speed and simplicity of this procedure suggest that it may be useful for monitoring changes in lens pigment density in groups exposed to high levels of environmental, laboratory or industrial ultraviolet light.

Aging↗