Left-handedness in male-to-female transsexuals.
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Female↗
Biomedical subjects
S Coren
Publications and source records attributed to S Coren.
The development and cross-validation of a self-report inventory to assess pure-tone threshold hearing sensitivity.
Previous attempts to assess hearing loss by means of self-report survey items have shown only low to moderate correlations with actual audiometric measures, probably because these attempts used items with high face validity rather than laboratory-tested validity. Beginning with a pool of 108 items used with 384 individuals, we developed a self-report inventory (see Appendix) suitable for group testing or survey administration, which appears to have high correlation with pure-tone hearing thresholds. The inventory was then cross-validated against laboratory audiometric measures in a separate sample of 422 subjects. The resulting 12-item Hearing Screening Inventory (HSI) was shown to be reliable with an internal consistency coefficient (alpha) of 0.89 and test-retest stability coefficient of 0.88. The correlation between pure-tone hearing thresholds in the better ear and the HSI scores for the combined samples was r = 0.81. The correct classification rate for the HSI was 92.1% for a low fence of 25-dB hearing level and 93.4% for a high fence of 55-dB hearing level. A conversion equation with estimated variability is also provided for point estimates of pure-tone hearing thresholds from the HSI scores. A copy of the inventory and scoring procedure is appended to this report.
Adult↗
Amodal completion, depth stratification, and illusory figures: a test of Kanizsa's explanation.
Subjective contours have been explained by Kanizsa as being a consequence of amodal completion of incomplete figures. According to the theory of amodal completion, figural incompleteness triggers the emergence of an illusory object superimposed on the gaps in the inducers, which in turn hide parts of the pattern, thus suggesting that the plane of the illusory object must always be seen to be above the plane of the inducers. A figure was created in which subjective contours are seen despite the fact that the perceived depth relationships run counter to that required by the theory of amodal completion. In four experiments, this depth relationship is confirmed by using direct and indirect measures which assess both registered and apprehended depth. By emphasizing a logical inconsistency in the explanation based on amodal completion, the results show that amodal completion, at least in Kanizsa-like patterns, cannot be considered as a causal factor for subjective contour figures.
Adult↗
Handedness, traffic crashes, and defensive reflexes.
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Accidents, Traffic↗
The moon illusion: a different view through the legs.
The fact that the overestimation of the horizon moon is reduced when individuals bend over and view it through their legs has been used as support for theories of the moon illusion based upon angle of regard and vestibular inputs. Inversion of the visual scene, however, can also reduce the salience of depth cue, so illusion reduction might be consistent with size constancy explanations. A sample of 70 subjects viewed normal and inverted pictorial arrays. The moon illusion was reduced in the inverted arrays, suggesting that the "through the legs" reduction of the moon illusion may reflect the alteration in perceived depth associated with scene inversion rather than angle of regard or vestibular effects.
Cues↗
Subjective contours 1900-1990: research trends and bibliography.
A bibliography on subjective contours and a brief summary of trends in research on this problem are presented. The bibliography covers the years 1900-1990 and contains 445 entries, each briefly annotated with a code that indicates the general content and theoretical orientation of the item.
Form Perception↗
Left-handedness: a marker for decreased survival fitness.
Life span studies have shown that the population percentage of left-handers diminishes steadily, so that they are drastically underrepresented in the oldest age groups. Data are reviewed that indicate that this population trend is due to the reduced longevity of left-handers. Some of the elevated risk for sinistrals is apparently due to environmental factors that elevate their accident susceptibility. Further evidence suggests that left-handedness may be a marker for birth stress related neuropathy, developmental delays and irregularities, and deficiencies in the immune system due to the intrauterine hormonal environment. Some statistical and physiological factors that may cause left-handedness to be selectively associated with earlier mortality are also presented.
Functional Laterality↗
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↗
Left-handedness in offspring as a function of maternal age at parturition.
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Adult↗
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↗
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↗
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↗
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↗
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↗
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↗
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↗