查看更多>>摘要：This study sought to test the hypothesis that significant differences would be observed in clinical measures, symptoms, and objective assessments of vergence eye movements between children with typically developing convergence insufficiency (TYP-CI) and children with persistent post-concussion symptoms with convergence insufficiency (PPCS-CI). Data from age-matched binocularly normal controls (BNC) were used for comparison. Data from three groups of children 11 to 17 years of age are presented: BNC (N = 11), TYP-CI (N = 10), and PPCS-CI (N = 15). Clinical measures of vergence, accommodation, and symptom severity were collected. Symmetrical 4 degrees disparity vergence eye movements were quantified with an eye tracker integrated into a head-mounted display (Oculus DK2). Peak velocity and final response amplitude of convergence and divergence eye movement responses were assessed. The mean near point of convergence (break) was more receded (worse), the amplitude of accommodation more deficient, and convergent and divergent peak velocities slower in the PPCS-CI group compared with the TYP-CI and BNC groups. These results suggest that PPCS-CI may be a different clinical entity than TYP-CI. Hence, more research is warranted to determine whether the therapeutic interventions that are effective for TYP-CI can also be used for PPCS-CI populations.
查看更多>>摘要：This study sought to test the hypothesis that significant differences would be observed in clinical measures, symptoms, and objective assessments of vergence eye movements between children with typically developing convergence insufficiency (TYP-CI) and children with persistent post-concussion symptoms with convergence insufficiency (PPCS-CI). Data from age-matched binocularly normal controls (BNC) were used for comparison. Data from three groups of children 11 to 17 years of age are presented: BNC (N = 11), TYP-CI (N = 10), and PPCS-CI (N = 15). Clinical measures of vergence, accommodation, and symptom severity were collected. Symmetrical 4 degrees disparity vergence eye movements were quantified with an eye tracker integrated into a head-mounted display (Oculus DK2). Peak velocity and final response amplitude of convergence and divergence eye movement responses were assessed. The mean near point of convergence (break) was more receded (worse), the amplitude of accommodation more deficient, and convergent and divergent peak velocities slower in the PPCS-CI group compared with the TYP-CI and BNC groups. These results suggest that PPCS-CI may be a different clinical entity than TYP-CI. Hence, more research is warranted to determine whether the therapeutic interventions that are effective for TYP-CI can also be used for PPCS-CI populations.
查看更多>>摘要：Theoretical studies suggest that several mechanisms underlie human visual aesthetic experiences: perceptual processing, which has small variability among individuals (shared properties) and strong correlation with image statistics (e.g. color statistics); cognitive processing, which is idiosyncratic and has weak correlation with image statistics; and emotional processing, which determines the affective part of the aesthetic experience. Furthermore, several experimental studies have reported that the visual aesthetic experience can be largely explained by only a few latent factors. However, it is unclear whether the idiosyncrasy and sensitivity to the image statistics of the latent factors from empirical studies are consistent with the multi-stage processing hypothesis from theoretical studies. In the present study, using exploratory factor analysis, we derived three latent factors of visual aesthetic experiences from participants observing landscape paintings and photographs. Then we examined the difference in the idiosyncrasy of the factors and the relationship between the factors and color statistics. We found that there were significant correlations among the color statistics and Factors 1 and 3, which had a small variance of factor scores (low idiosyncrasy), and no or weak correlation among the color statistics and Factor 2, which had a large variance of factor scores (high idiosyncrasy). Our results provide experimental evidence for the perceptual and cognitive processing of visual aesthetic experiences.
查看更多>>摘要：Theoretical studies suggest that several mechanisms underlie human visual aesthetic experiences: perceptual processing, which has small variability among individuals (shared properties) and strong correlation with image statistics (e.g. color statistics); cognitive processing, which is idiosyncratic and has weak correlation with image statistics; and emotional processing, which determines the affective part of the aesthetic experience. Furthermore, several experimental studies have reported that the visual aesthetic experience can be largely explained by only a few latent factors. However, it is unclear whether the idiosyncrasy and sensitivity to the image statistics of the latent factors from empirical studies are consistent with the multi-stage processing hypothesis from theoretical studies. In the present study, using exploratory factor analysis, we derived three latent factors of visual aesthetic experiences from participants observing landscape paintings and photographs. Then we examined the difference in the idiosyncrasy of the factors and the relationship between the factors and color statistics. We found that there were significant correlations among the color statistics and Factors 1 and 3, which had a small variance of factor scores (low idiosyncrasy), and no or weak correlation among the color statistics and Factor 2, which had a large variance of factor scores (high idiosyncrasy). Our results provide experimental evidence for the perceptual and cognitive processing of visual aesthetic experiences.
Lindsey, Delwin T.Brown, Angela M.Hutchinson, Lindsey N.
11页
查看更多>>摘要：Deuteranomalous color matching behavior is different from normal because the middle-wavelength sensitive cones contain an abnormal L' pigment instead of the M pigment of the normal observer. However, there is growing evidence that deuteranomalous color experience is not very different from that of normal trichromats. Here, normal and deuteranomalous observers chose monochromatic unique yellow lights. They also chose broadband lights, displayed on a computer monitor, that corresponded to eight special colors: the Hering unique hues (red, yellow, green, blue), and binary colors perceptually midway between them (orange, lime, cyan, purple). Deuteranomalous monochromatic unique yellow was shifted towards red, but all the broadband special color selections were physically similar for normal and deuteranomalous observers. Deuteranomalous special colors, including monochromatic unique yellow, were similar to those of normal observers when expressed in a color-opponent chromaticity diagram based on their own visual pigments, but only if (1) color-opponent responses were normalized to white, and (2) the deuteranomalous diagram was expanded along the r - g dimension to compensate for the reduced difference between deuteranomalous L- and L'-cone photopigments. Particularly, deuteranomalous observers did not choose binary colors with extra r - g impact to overcome their insensitivity along the r - g dimension. This result can only be compatible with the known abnormality of the deuteranomalous L' photopigment if deuteranomalous observers adjust their perceptual representation of colors to compensate for their color vision deficiency.
Lindsey, Delwin T.Brown, Angela M.Hutchinson, Lindsey N.
11页
查看更多>>摘要：Deuteranomalous color matching behavior is different from normal because the middle-wavelength sensitive cones contain an abnormal L' pigment instead of the M pigment of the normal observer. However, there is growing evidence that deuteranomalous color experience is not very different from that of normal trichromats. Here, normal and deuteranomalous observers chose monochromatic unique yellow lights. They also chose broadband lights, displayed on a computer monitor, that corresponded to eight special colors: the Hering unique hues (red, yellow, green, blue), and binary colors perceptually midway between them (orange, lime, cyan, purple). Deuteranomalous monochromatic unique yellow was shifted towards red, but all the broadband special color selections were physically similar for normal and deuteranomalous observers. Deuteranomalous special colors, including monochromatic unique yellow, were similar to those of normal observers when expressed in a color-opponent chromaticity diagram based on their own visual pigments, but only if (1) color-opponent responses were normalized to white, and (2) the deuteranomalous diagram was expanded along the r - g dimension to compensate for the reduced difference between deuteranomalous L- and L'-cone photopigments. Particularly, deuteranomalous observers did not choose binary colors with extra r - g impact to overcome their insensitivity along the r - g dimension. This result can only be compatible with the known abnormality of the deuteranomalous L' photopigment if deuteranomalous observers adjust their perceptual representation of colors to compensate for their color vision deficiency.
查看更多>>摘要：Defocus blur and spatial attention both act on our ability to see clearly over time. However, it is currently unknown how these two factors interact because studies on spatial resolution only focused on the separate effects of attention and defocus blurs. In this study, eleven participants performed a resolution acuity task along the diagonal 135 degrees/315 degrees with horizontal, at 8 degrees eccentricity for clear and blurred Landolt C images under various manipulations of covert endogenous attention. All the conditions were interleaved and viewed binocularly on a visual display. We observed that attention not just improves the resolution of clear stimuli, but also modulates the resolution of defocused stimuli for compensating the loss of resolution caused by retinal blur. Our results show, however, that as the degree of attention decreases, the differences between clear and blurred images largely diminish, thus limiting the benefit of an image quality enhancement. It also appeared that attention tends to enhance the resolution of clear targets more than blurred targets, suggesting potential variations in the gain of vision correction with the level of attention. This demonstrates that the interaction between spatial attention and defocus blur can play a role in the way we see things. In view of these findings, the development of adaptive interventions, which adjust the eye's defocus to attention, may hold promise.
查看更多>>摘要：Defocus blur and spatial attention both act on our ability to see clearly over time. However, it is currently unknown how these two factors interact because studies on spatial resolution only focused on the separate effects of attention and defocus blurs. In this study, eleven participants performed a resolution acuity task along the diagonal 135 degrees/315 degrees with horizontal, at 8 degrees eccentricity for clear and blurred Landolt C images under various manipulations of covert endogenous attention. All the conditions were interleaved and viewed binocularly on a visual display. We observed that attention not just improves the resolution of clear stimuli, but also modulates the resolution of defocused stimuli for compensating the loss of resolution caused by retinal blur. Our results show, however, that as the degree of attention decreases, the differences between clear and blurred images largely diminish, thus limiting the benefit of an image quality enhancement. It also appeared that attention tends to enhance the resolution of clear targets more than blurred targets, suggesting potential variations in the gain of vision correction with the level of attention. This demonstrates that the interaction between spatial attention and defocus blur can play a role in the way we see things. In view of these findings, the development of adaptive interventions, which adjust the eye's defocus to attention, may hold promise.
Nascimento, Sergio M. C.Albers, Anke MaritGegenfurtner, Karl R.
13页
查看更多>>摘要：What makes a colored image, e.g. an abstract painting or a landscape, look pleasing? We hypothesized that a preference for complex color compositions, such as paintings and images of natural scenes, might be related to how natural the colors are perceived. We tested this possibility with two experiments in which the degree of naturalness of images was manipulated by rotating their color gamut rigidly in the color space CIELAB. This changed just the hue composition, but preserved saturation and lightness. In the first experiment we obtained individual scaling curves for perceived naturalness and for preference as a function of the angle of gamut rotation for a small set of images. The naturalness and preference scaling curves were found to be largely similar and their maxima were close to the original image. In the second experiment, we tested whether this effect generalized to a larger set of images. We used a simultaneous 5AFC procedure where in each trial participants had to select the most natural or the most preferred image from five different rotations of the color gamut. The results confirmed the first experiment and showed that, in general, the images perceived as the more natural tend to be the ones that are preferred. Together these results show that perceived naturalness and preference are indeed perceptually closely related and may be driven by related mechanisms.
Nascimento, Sergio M. C.Albers, Anke MaritGegenfurtner, Karl R.
13页
查看更多>>摘要：What makes a colored image, e.g. an abstract painting or a landscape, look pleasing? We hypothesized that a preference for complex color compositions, such as paintings and images of natural scenes, might be related to how natural the colors are perceived. We tested this possibility with two experiments in which the degree of naturalness of images was manipulated by rotating their color gamut rigidly in the color space CIELAB. This changed just the hue composition, but preserved saturation and lightness. In the first experiment we obtained individual scaling curves for perceived naturalness and for preference as a function of the angle of gamut rotation for a small set of images. The naturalness and preference scaling curves were found to be largely similar and their maxima were close to the original image. In the second experiment, we tested whether this effect generalized to a larger set of images. We used a simultaneous 5AFC procedure where in each trial participants had to select the most natural or the most preferred image from five different rotations of the color gamut. The results confirmed the first experiment and showed that, in general, the images perceived as the more natural tend to be the ones that are preferred. Together these results show that perceived naturalness and preference are indeed perceptually closely related and may be driven by related mechanisms.
NSTL
Elsevier