Unstable ocular dominance and reading ability

An ocular anomaly, unstable ocular dominance, has been shown to be associated with poor reading performance in clinically selected subjects. A study is reported in which this anomaly was examined in a nonclinical sample. Two groups of children of similar reading performance and IQ but differing in chronological age were selected. The older children had a mean discrepancy between their reading and chronological age of 19 months. Unstable ocular dominance was more frequent in these poor readers. The hypothesis that this instability would lead to more errors and longer decision times for distinguishing left-right mirror-image figures was not supported. If unstable ocular dominance is to be established as anything other than a correlate of specific reading retardation, it is necessary to establish the processes through which it is operative. These have yet to be determined.     

Colavita dominance effect revisited: the effect of semantic congruity

To investigate the effect of semantic congruity on audiovisual target responses, participants detected a semantic concept that was embedded in a series of rapidly presented stimuli. The target concept appeared as a picture, an environmental sound, or both; and in bimodal trials, the audiovisual events were either consistent or inconsistent in their representation of a semantic concept. The results showed faster detection latencies to bimodal than to unimodal targets and a higher rate of missed targets when visual distractors were presented together with auditory targets, in comparison to auditory targets presented alone. The findings of Experiment 2 showed a cross-modal asymmetry, such that visual distractors were found to interfere with the accuracy of auditory target detection, but auditory distractors had no effect on either the speed or the accuracy of visual target detection. The biased-competition theory of attention (Desimone & Duncan Annual Review of Neuroscience 18: 1995; Duncan, Humphreys, & Ward Current Opinion in Neurobiology 7: 255–261 1997) was used to explain the findings because, when the saliency of the visual stimuli was reduced by the addition of a noise filter in Experiment 4, visual interference on auditory target detection was diminished. Additionally, the results showed faster and more accurate target detection when semantic concepts were represented in a visual rather than an auditory format.     

Repetition effect with picture stimuli: Possible implications for clarity

Increasing recognition accuracy with repeated presentations was demonstrated for complex pictorial stimuli (real-world photographs) by accuracy, signal detection, and confidence of decision indicators. Consistent with other research, the effect occurred only for short stimulus durations. The effect occurred for both old and new pictures, the rate of improvement being greater for old than for new pictures. Experiment II utilized focus-degraded stimuli to demonstrate that amount of information artifacts were not responsible for the observed differences between responses to old and new pictures.     

The relationship between sighting dominance and the fading of a stabilized retinal image

The fading of a stabilized retinal image in the sighting and the nonsighting dominant eye was studied using the Haidinger’s brush target. Reaction time to the complete disappearance of the stabilized image was significantly longer when the target was input to the sighting eye. The greater persistence of stabilized targets in the sighting eye suggests possible differences in the neural channels from the two eyes or processing differences in the two monocular channels that are related behaviorally to eye dominance.     

Rivalry with continuous and flashed stimuli as a measure of ocular dominance across the visual field

Two measures of sensory ocular dominance were compared. Both involved dichoptic presentation of orthogonal gratings--a situation which results in binocular rivalry. The gratings were presently briefly in experiment 1 and continuously in experiment 2 and by the predominance of one grating over the other a quantitative estimation of ocular dominance was obtained in both cases. Comparison of the results showed that (a) binocular rivalry suppression was present for exposures of 250 ms and (b) the briefly presented gratings were a more sensitive test for ocular dominance than conventional continuously presented stimuli. The variation of dominance over the horizontal meridian of the visual field was considered. For many subjects a consistent different in the ocular dominance in the two halves of the visual field, and therefore of the cortex, was found. Some showed dominance of the ipsilateral eye in each hemisphere while others showed dominance of the contralateral eye. It was found that there is, in fact, a continuum of types of dominance pattern amongst individuals.     

Visual dominance and attention: the Colavita effect revisited

Under many conditions, humans display a robust tendency to rely more on visual information than on other forms of sensory information. Colavita (1974) illustrated this visual dominance effect by showing that naive observers typically fail to respond to clearly suprathreshold tones if these are presented simultaneously with a visual target flash. In the present study, we demonstrate that visual dominance influences performance under more complex stimulation conditions and address the role played by attention in mediating this effect. In Experiment 1, we show the Colavita effect in the simple speeded detection of line drawings and naturalistic sounds, whereas in Experiment 2 we demonstrate visual dominance when the task targets (auditory, visual, or bimodal combinations) are embedded among continuous streams of irrelevant distractors. In Experiments 3-5, we address the consequences of varying the probability of occurrence of targets in each sensory modality. In Experiment 6, we further investigate the role played by attention on visual dominance by manipulating perceptual load in either the visual or the auditory modality. Our results demonstrate that selective attention to a particular sensory modality can modulate--although not completely reverse--visual dominance as illustrated by the Colavita effect.     

A semi-persistent adult ocular dominance plasticity in visual cortex is stabilized by activated CREB

The adult cerebral cortex can adapt to environmental change. Using monocular deprivation as a paradigm, we find that rapid experience-dependent plasticity exists even in the mature primary visual cortex. However, adult cortical plasticity differs from developmental plasticity in two important ways. First, the effect of adult, but not juvenile monocular deprivation is strongly suppressed by administration of barbiturate just prior to recording visual evoked potentials, suggesting that the effect of adult experience can be inactivated acutely. Second, the effect of deprivation is less persistent over time in adults than in juveniles. This correlates with the known decline in CREB function during maturation of the visual cortex. To compensate for this decline in CREB function, we expressed persistently active VP16-CREB and find that it causes adult plasticity to become persistent. These results suggest that in development and adulthood, the regulation of a trans-synaptic signaling pathway controls the adaptive potential of cortical circuits.     

Self-esteem and clarity of the self-concept

This article examines the association between evaluative and knowledge components of the self. Four studies tested the hypothesis that the self-concepts of low-self-esteem (LSE) people are characterized by less clarity or certainty than those of high-self-esteem (HSE) people. LSE Ss exhibited less extremity and self-reported confidence when rating themselves on bipolar trait adjectives (Study 1), less temporal stability in their trait ratings over a 2-month interval (Study 2), less congruence between their self-concepts and their subsequent perceptions of situation-specific behavior and memory for prior behavior (Study 3), and less internal consistency, lower self-rated confidence, and longer reaction times when making me/not me responses to pairs of opposite traits (Study 4). Alternative accounts of the results and the implications of self-concept clarity for understanding the pervasive impact of self-esteem on behavior are discussed.     

视听刺激突显性对视觉主导效应的影响

本研究使用空间任务-转换范式,控制视、听刺激的突显性,探讨自下而上注意对视觉主导效应的影响。结果表明视、听刺激突显性显著地影响视觉主导效应,实验一中当听觉刺激为高突显性时,视觉主导效应显著减弱。实验二中当听觉刺激为高突显性并且视觉刺激为低突显性时,视觉主导效应进一步减弱但依然存在。结果支持偏向竞争理论,在跨通道视听交互过程中视觉刺激更具突显性,在多感觉整合过程中更具加工优势。     

Vagueness,uncertainty and degrees of clarity

In this paper we compare different models of vagueness viewed as a specific form of subjective uncertainty in situations of imperfect discrimination. Our focus is on the logic of the operator “clearly” and on the problem of higher-order vagueness. We first examine the consequences of the notion of intransitivity of indiscriminability for higher-order vagueness, and compare several accounts of vagueness as inexact or imprecise knowledge, namely Williamson’s margin for error semantics, Halpern’s two-dimensional semantics, and the system we call Centered semantics. We then propose a semantics of degrees of clarity, inspired from the signal detection theory model, and outline a view of higher-order vagueness in which the notions of subjective clarity and unclarity are handled asymmetrically at higher orders, namely such that the clarity of clarity is compatible with the unclarity of unclarity.     

The ground dominance effect in the perception of 3-D layout

The relative effectiveness of the ground surface and other environmental surfaces (the ceiling and sidewalls) in determining perceived layout was investigated in five experiments and a real-world demonstration. In the first three experiments, two vertical or horizontal posts were positioned between two surfaces (ground and ceiling in all three experiments, left wall and right wall in Experiment 1), and optical contact was manipulated so that the two surfaces provided contradictory information about the relative distances of the posts. Observers judged which of the two posts appeared to be closer. In Experiment 4, to control the height on the posts at which the distance judgments were made, a blue dot was attached to both vertical posts at varying heights and observers judged which dot appeared closer. In Experiment 5, the posts were replaced by two gray ellipses to eliminate the effects of the regular shape and texture. Our findings were that (1) among all four surfaces tested, observers showed a preference to respond according to the optical contact information provided by the ground surface--a ground dominance effect, (2) this effect did not depend on the height of the posts in the image, (3) as the scene was tilted away from a ground/ceiling orientation, the ground dominance effect decreased, and (4) this effect was not due to the location of the judgment.     

Rhythm and dominance

Subjects were tested by a short experimental procedure involving tapping of a rhythm with one limb with a simultaneous regular beat with another limb. Informal observations had suggested a rhythm dominance effect—that is was dramatically easier with some limb combinations. Notably it was easy when the right hand tapped the rhythm and the left hand the beat but almost impossible the other way round. Equally, both hands dominated both feet. Our tests revealed enormous individual differences, subjects separating neatly into three groups. Some people could not do the task at all, some could do it with any limb combination, the latter group including all the serious musicians tested. For the remainder the rhythm dominance effect was clear. However, the laterality effect was the same (right hand advantage) for a majority (60%) of left handers. We conclude, then, that this effect is linked to language dominance and not handedness. In addition it seems there is a task scheduler which imposes its own view in combining this laterality effect with the dominance of hands over feet.     

Rumination,emotional intensity and emotional clarity

It has been suggested that a high tendency to ruminate presents a deficient emotion regulation. Past research found that people with high tendency to ruminate show sustained attention for negative stimuli and increased negative thinking, which may result in intensified experiences of negative emotions. Moreover, high level of rumination was associated with low emotional understanding. Accordingly, we hypothesized (1) high ruminators (HR) experience more intense emotional reactions than low ruminators (LR) for negative but not positive emotions, (2) LR have higher emotional clarity than HR, and (3) there would be the same pattern of results for brooding but not for reflective pondering. Participants completed a demographic questionnaire, a rumination response style questionnaire, and the Beck Depression Inventory-II. They also rated emotional intensity and identified emotion type for scene pictures from the CAP-D (Categorized Affective Pictures Database). The highest (HR) and lowest (LR) quarters of ruminators were compared on levels of emotional intensity and emotional clarity. We found HR experienced negative emotions more intensely than LR, with no difference for positive emotions. In contrast to our hypothesis, the two groups did not differ in their emotion understanding. This pattern of results was found for brooding but not for reflective pondering. Our research sheds light on the mechanism underlying rumination and emotion regulation.     

Sex characteristics,task clarity,and authority

This study was conducted to investigate the effect of sexual stereotyping on the exercise of authority. The hypotheses were that the sexual composition of the group affects the authority behavior of group leaders when the task has low clarity but that sex characteristics have no effect on authority behavior when the task has high clarity. These predictions were expected to hold both in situations where there is a direct association between sex and the task ability and in situations where no such connection is established. As predicted, no significant difference was found in the number of high control acts made by male and female leaders in the high task clarity conditions, even when sex was directly related to the task ability. Also as hypothesized, sex effects did operate strongly in the low task clarity conditions. Male leaders made significantly more high control acts than female leaders, even in conditions where no prior relation was established between sex and the task ability. Thus, these results indicate that the effect of sex characteristics on the exercise of authority is enhanced in low task clarity situations and is neutralized in high task clarity situations.A preliminary version of this paaper was presented at the West Coast Conference for Small Group Research, San Francisco, California, April 24, 1974. We would like to acknowledge the comments made by Anne McMahon and Mary Walshok and the research assistance provided by Sue Aldrich, Patti Baird, Jim Hart, Debbie Jones, Glenn Kassel, Jane Morrison, Karen Scheblein, and Kay Smith.     

Stimulus dominance and ear dominance in the perception of dichotic voicing contrasts

Two studies were conducted to determine the effect of variations in voice onset time (VOT) on the perception of dichotic stop-consonant-vowel syllables contrasting in the voicing feature. The dichotic stimuli were partially fused, so that only a single response was required. Variations in VOT had a systematic effect on the probability of hearing the fused stimuli as voiced or voiceless. Changing the VOT of a voiceless stimulus had a larger effect than changing the VOT of a voiced stimulus. Unless one of the competing stimuli was close to the category boundary, the perceptual integration of their VOTs seemed to be roughly additive. The relative phase of the periodic portions of the stimuli had an unexpected effect on perception that remains to be explained. A number of subjects showed very strong right-ear dominance in these tests. The range and reliability of the laterality effects obtained, as well as certain other methodological features, make the present tests promising as tools for assessing individual differences in ear dominance.