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981.
The accommodative response to subthreshold blur and to perceptual fading during the Troxler phenomenon 总被引:2,自引:0,他引:2
A study is reported which shows that accommodation can be stimulated by a blur stimulus which is below the threshold for visual perception. It is also shown that perceptual fading of the target, caused by stabilization of the retinal image (Troxler phenomenon), can eliminate the accommodative response causing it to default to its resting level. The first finding suggests a way in which the visual system can filter the percept of blur out of our conscious awareness and still effectively utilize the blur as a steady-state error for the accommodative control system. The second finding is consistent with a locus for the Troxler phenomenon in the early afferent part of the visual pathway, ie the retinal ganglion cells. 相似文献
982.
The role of spatial-frequency channels in the perception of local and global structure 总被引:5,自引:0,他引:5
Adaptation and reaction-time techniques were used to examine the role of different spatial-frequency channels in the perception of local and global structure. Subjects were shown figures consisting of a large C composed of smaller Cs and asked to identify the orientation of either the global C or its local elements. Prior to performing the task subjects were adapted to different spatial frequencies and the effect on subsequent performance was assessed. Two main results were found. First, the adapting frequency that most affected the global task was often lower than that most affecting the local task, suggesting that high and low frequencies independently code the structure of an image. Second, reaction time to global figures was often faster than to local figures at all levels of detectability, again suggesting a role of low-frequency channels in global processing. 相似文献
983.
Static depiction of movement 总被引:1,自引:0,他引:1
A number of pictorial devices were compared in order to assess their relative effectiveness in depicting events. Effectiveness, as measured by a rating task, did not seem to be a function of the classification of a device as natural or metaphorical. Rather, it depended on whether a given device highlighted a distinctive aspect of a particular event (running, jumping, or moving), or simply modified the event. This observation was buttressed by the existence in a forced-choice task of a category boundary for depictions of running (pictures with a certain device were seen as running, those without it were not) but not for moving or jumping. Even preschool children displayed some understanding of metaphorical devices. They chose figures with those devices as running faster than the experimental standard. Results are discussed in the context of Kennedy's characterization of pictorial metaphors and Gibson's framework for understanding the relationship between pictorial and environmental information. 相似文献
984.
Earlier studies have shown the girls spend more time than boys in activities that are highly structured by adults. Structured activities may encourage feminine sex-typed behaviors such as compliance to adults; low-structure activities may encourage masculine sex-typed behaviors such as independence and assertiveness. In the present study the effects of high or low levels of adult structuring on children's social behavior during preschool free-play activities were tested in a field experiment carried out during an entire semester in one preschool classroom. For the first 15 minutes of free play, children were assigned to high- or low-structure activities. As predicted, when children were in high-structure activities, they exhibited high rates of bids for recognition and compliance to adults; in low-structure activities, they exhibited peer-directed leadership, bids for recognition, and compliance. There were no generalized effects of these treatments on their subsequent free choice of activities or social behavior. The study demonstrates powerful effects of naturally occurring variations in children's play activities on sex-typed social behaviors. 相似文献
985.
This study examined the relationship of parental education, race, and gender to sex-role stereotyping in five-year-old kindergartners. A significant effect for race and parental education level was noted. White children gave more stereotyped responses than did black children, and children whose parents were in the middle- and high-educational levels gave more stereotyped responses than did children whose parents were in the low-educational level. A significant interaction was also found between educational level of parents and race. White children tended to give more stereotyped responses as the educational level of their parents increased; this trend was not evident for black children. No significant differences in stereotyping were noted between the sexes.To whom requests for reprints or information concerning the Bardwell-Sietsema Sex Stereotype Scale should be addressed at Department of Elementary Education, East Texas State University, Commerce, Texas 75428. 相似文献
986.
987.
988.
San Diego suicide study: comparison of gay to straight males 总被引:1,自引:0,他引:1
Previous large studies of completed suicides have not considered sexual orientation in their data analyses. In this study, data from the known homosexual subpopulation (13 males, aged 21-42) in a series of 283 suicides were examined. They were compared with all other aged male suicides 21-42 (n = 106). Both groups showed considerable substance abuse plus a variety of other psychiatric diagnoses. Both also had a high frequency of relationship difficulties near the time of death. Gays who committed suicide did not have a history of more police trouble and were no more likely to be living alone than the comparison group. They did not have more prior suicide attempts or previous psychiatric treatment. We conclude that, among the factors examined here, there appears to be little difference between gay and heterosexual male suicides. 相似文献
989.
Younger adult students between 19 and 24 years of age (M = 21.3 years), older adult students between 61 and 76 years of age (M = 67.9 years), and older adult nonstudents between 62 and 76 years of age (M = 68.5 years) were assessed for health (self-ratings of physical and mental health), social functioning (self-ratings of physical and mental activity, perceived role activity level, perceived roles, locus of control, and age-norm expectations), and cognitive functioning (Wechsler Adult Intelligence Scale-Revised vocabulary and block design, and paired associate memory). Age differences were observed in self-ratings of health, social roles, intellectual performance, and memory. No student status differences were observed. The results are discussed in terms of plasticity of intellectual function and characteristics of student status in later adulthood. 相似文献
990.
Modest decrements in both taste threshold sensitivity and, more recently, suprathreshold sensitivity have been associated with the aging process. The present study was designed to investigate the existence of changes in preference for various concentrations of single tastes and of the same single tastes in more complex chemosensory mixtures. In this study, 300 participants from three different age groups (18-26, 32-45, over 65) rated for pleasantness four concentrations of sodium chloride, sucrose, and citric acid presented in both aqueous and beverage bases. Results showed significant effects of age, stimulus background, stimulus, concentration, and of several interactions, and they suggest that elderly subjects find salt and sugar pleasanter at higher concentrations than younger subjects do. 相似文献