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PubMed1983

Responses to interpersonal confrontation: interactions with human movement and color perception.

Two videotapes designed to present varying levels of interpersonal confrontation potential were viewed by 48 student volunteer subjects. Verbal responses to the tapes were recorded, and state anxiety in response to each tape was assessed by the State-Trait Anxiety Inventory. Subjects' experience balances were computed based on the ratio of human movement responses to color responses on the Holtzman Inkblot Technique. It was found that introversive individuals showed increased response latency and state anxiety in response to the increase in interpersonal confrontation, whereas extratensive and ambiequal individuals showed only increased response latency or state anxiety, respectively. Implications are discussed in terms of interpretation of the experience balance itself and more generally in terms of personality-situation interactions and personality assessment research strategies.

Anxiety↗
PubMed1999

Unconscious letter discrimination is enhanced by association with conscious color perception in visual form agnosia.

Adaptive behavior guided by unconscious visual cues occurs in patients with various kinds of brain damage as well as in normal observers, all of whom can process visual information of which they are fully unaware [1] [2] [3] [4] [5] [6] [7] [8]. Little is known on the possibility that unconscious vision is influenced by visual cues that have access to consciousness [9]. Here we report a 'blind' letter discrimination induced through a semantic interaction with conscious color processing in a patient who is agnosic for visual shapes, but has normal color vision and visual imagery. In seeing the initial letters of color names printed in different colors, it is normally easier to name the print color when it is congruent with the initial letter of the color name than when it is not [10]. The patient could discriminate the initial letters of the words 'red' and 'green' printed in the corresponding colors significantly above chance but without any conscious accompaniment, whereas he performed at chance with the reverse color-letter mapping as well as in standard tests of letter reading. We suggest that the consciously perceived colors activated a representation of the corresponding word names and their component letters, which in turn brought out a partially successful, unconscious processing of visual inputs corresponding to the activated letter representations.

Adult↗
PubMed1974

Infant color perception.

Human infants 4 to 6 months of age devoted more visual fixation to checkerboards composed of two Munsell hues equated for brightness and saturation than to unpatterned targets of either hue. Strength of pattern preference was positively related to degree of hue difference in the checkerboards.

Age Factors↗
PubMedDate not supplied

[Constancy of color perception in the gray toad (Bufo bufo L.)].

Colour vision and constancy of colour perception in Bufo bufo L, were examined by means of unconditioned reaction of choosing moving and stationary models of females by males during breeding season. The males chose blue and dark blue models. Control of the choice of blue models presented in pairs with models of different shades of grey proves the existence of colour vision in Bufo bufo L. The choice of blue models has been observed under significantly varying conditions: both with artificial illumination and in sunlight. This attests the capacity of toads for constant colour perception. When a model was presented against a saturated red background, colour contrast was observed: under such conditions the toads chose the grey models which evoked no reactions when presented against white background.

Animals↗
PubMed2005

The highest luminance anchoring rule in achromatic color perception: some counterexamples and an alternative theory.

It has been hypothesized that lightness is computed in a series of stages involving: (1) extraction of local contrast or luminance ratios at borders; (2) edge integration, to combine contrast or luminance ratios across space; and (3) anchoring, to relate the relative lightness scale computed in Stage 2 to the scale of real-world reflectances. The results of several past experiments have been interpreted as supporting the highest luminance anchoring rule, which states that the highest luminance in a scene always appears white. We have previously proposed a quantitative model of achromatic color computation based on a distance-dependent edge integration mechanism. In the case of two disks surrounded by lower luminance rings, these two theories--highest luminance anchoring and distance--dependent edge integration-make different predictions regarding the luminance of a matching disk required to for an achromatic color match to a test disk of fixed luminance. The highest luminance rule predicts that luminance of the ring surrounding the test should make no difference, whereas the edge integration model predicts that increasing the surround luminance should reduce the luminance required for a match. The two theories were tested against one another in two experiments. The results of both experiments support the edge integration model over the highest luminance rule.

Color Perception↗
PubMed1982

Color perception under chromatic adaptation: equilibrium yellow and long-wavelength adaptation.

Observers viewed a thin (0.8-1.3) annulus composed of a mixture of 540 and 660 nm monochromatic lights (denoted delta G and delta R, respectively). The annular mixture was superimposed upon a larger (2.7) 660 nm circular background field. The observer adjusted the radiance of either delta G or delta R so that the annulus appeared a perfect (i.e. neither reddish nor greenish) yellow. In the first experiment, the background and annulus both were presented steadily. The results showed that the background, varied over a range from 10 to 1000 td. always contributed less to the color appearance of the annular test area than would be expected from the simple admixture of lights. The second experiment examined the effect of briefly removing the background-field quanta during the period when the annulus was judged. After several minutes of adapting to the background, the background was momentarily extinguished for 1 sec once every 6 sec; the observer adjusted the radiance of delta R so that during the 1 sec period the continuously presented annular mixture appeared equilibrium yellow. With steady backgrounds, the delta G to delta R luminance ratio decreased with test annulus luminance; for judgments made while the background momentarily was extinguished, the luminance ratio generally increased with annulus luminance. All of the empirical observations can be accounted for quantitatively by a two-process theory of chromatic adaptation; in two processes are (1) gain changes and (2) a restoring signal that tends to drive back toward equilibrium the opponent response resulting from the adapting light. Results from a third experiment, in which the background-off interval was reduced from 1 sec to 500, 200 or 150 msec. also are consistent with this model.

Adaptation, Ocular↗
PubMed1980

[Color perception in domestic goats (Capra hircus L.)].

Tests on male goats were designed to determine their capacity for colour vision. The colours yellow, orange, blue, violet and green were tested against gray nuances of like brightness. Goats were found to be able to distinguish between colours and gray nuances. The rate of errors increased in the order: orange, green, red, yellow, violet, blue.

Animals↗
PubMed1984

Color perception under chromatic adaptation: "supersensitivity" with dim backgrounds.

The amounts of 540 nm light and 660 nm light that when mixed result in a yellow (neither reddish nor greenish) percept remain in constant ratio, regardless of the total retinal illumance level of the mixture. A similar result holds if the mixture is superimposed upon a very dim 660 nm adapting field, except that a larger proportion of 540 nm light is required than in the dark (contrary to an effect of receptor desensitization, which would result in a smaller proportion of 540 nm light). Mixtures of 460 and 579 nm lights that give yellow/blue equilibrium percepts show the same effect: under very dim 579 nm adaptation, a larger proportion of 460 nm light is required than in the dark. These results cannot be accounted for by cone sensitivity reduction nor by a postreceptoral restoring effect; they reveal an additional mechanism of adaptation.

Adaptation, Ocular↗
PubMedDate not supplied

[Work of the human visual system. III. Color perception space].

In the previous parts of this work the author presented thet expression for percieved colour: Ei=k1n(ai/ao) where k -- is the coefficient of proportionality which have dimension of sensation and ai, ao -- are the light actions in some retinal point and in the extreme periphery correspondingly. Here the author describes some consequences from this expression and gives a new conception about the space of colour sensations.

Color Perception↗
PubMed1990

[Changes in color perception during the use of the Vacumcolor 50% tinted glasses in normal trichromatic individuals].

The authors assessed the spectral absorption of coloured glasses Vacumcolor 50% and found differences between different pairs of glasses which attained in the red areas as much as 17%. They also examined changes of the colour sense in a group of normal trichromats when using these coloured glasses. They found that these glasses alter the colour sense in the direction of deuteranomaly and cause deterioration of colour asthenopia.

Adult↗
PubMedDate not supplied

[A model of constant color perception for continuous spectral functions].

A trichromatic model is proposed of constant pattern of colour perception (MCCP) for scenes with a single illumination source. In MCCP functions of the source emission, surface reflection, photoacceptor sensitivity are approximated by the normal distribution curves. MCCP characteristics "colour tone", "cleanness", and "lightness" organize its output colour metric by the human's pattern, and in a wide range of spectral composition of illumination they are invariant under these changes. Special colorimetric regime of MCCP work which estimates the colour of visual stimulus permits a comparison between the efficiencies of two proposed algorithms of visual information processing for MCCP.

Color Perception↗
PubMed1977

[Importance, especially in aeronautics, of color perception tests under dynamic conditions. Study of a suitable experimental apparatus].

Following a review of the most recent opinion on the physiology of colour vision, a device for examining it in dynamic, i.e. real-life conditions is described. The apparatus consist of two projectors which flash two absolutely identical pictures on to the screen, one of them is upside down. It appears at fixed but adjustable intervals so that the exposure time of the intelligible image can be varied. Subjects were also controlled with Ishihara charts and Nägel anomaloscope. The results are compared and point to the higher sensitivity of the dynamic test to even slight degrees of dyschromatopsia.

Color Perception Tests↗
PubMed1984

Color perception under contralateral and binocularly fused chromatic adaption.

Observers viewed a thin (1.0-1.5 degree) annular mixture of 450 plus 660 nm light with the left eye, and a 4.8 degrees circular 660 nm adapting field with the right eye. The annular test was centered upon the adapting field in the fused percept. The contralateral field, which bleached negligible photopigment, caused the test to appear more reddish; however quantitative results reject the hypothesis that a given contralateral 660 nm light simply adds redness to the test. Additional experiments with a separate 660 nm adapting light presented to each eye reveal that fused chromatic adapting fields affect a complex central mechanism. For example, a dim background presented to the same eye as the annular test can reduce the effect of an opposite-eye field, even when the dim test-eye background has no measurable influence in a purely monocular experiment.

Adaptation, Ocular↗
PubMedDate not supplied

[The spherical theory of color perception: its verification by the methods of psychophysics and neurophysiology].

In the paper data of experimental verification of "spherical theory of perception" (E. N. Sokolov) are summed on the material of colour perception study. The results of psychophysical experiments with subjects having different forms of colour perception (normal trichromats, colour anomalies) and neurophysiological experiments on animals (carp) are considered within single psychophysiological system--spherical model of colour discrimination. Neuron-like elements of the model reflect the activity of light-sensitive cells of the visual system and at the same time reproduce some rules of subjective colours discrimination at the psychophysical level. Advantages of spherical model are considered allowing to analyze human individual colour functions in norm and pathology and giving the opportunity of strictly quantitative approach to description of neuronal mechanisms of colour vision. From the position of spherical model of colour discrimination neuronal structure of colour analyzer is discussed, which includes layers of photoreceptors, ++predetectors (colour-opponent and achromatic cells) and colour-selective detectors.

Animals↗
PubMed1992

The dermo-optical perception of color as an information source for blind travelers.

Dermo-optical color perception refers to a person's ability to distinguish color surfaces through "skin perception" without the use of sight. The aims of this study were (1) to assess prior research findings which apparently demonstrated the existence of dermo-optical color perception and (2) to explore the possibilities of using color to indicate reference points for blind travellers. Three experiments were conducted with 20 congenitally blind subjects and a sighted blindfolded control group matched on age, sex, and education. In Exp. 1 on a discrimination task subjects were asked if two boards were of the same color and on a pairing task were asked to match a colored board with one among a set of three boards having the same color. In Exp. 2 the discrimination task was identical to that in Exp. 1, but instead of using boards perceived through haptic exploration, we used colored cubicles in which the whole body would be exposed to the color. In Exp. 3 subjects were asked to walk along the corridor of a labyrinthine set-up and to identify any changes of color they could perceive. The experiments were designed to provide measures of reliability of subjects' responses. Analysis showed little or no support for the ability to perceive color by dermo-optical means. The comparisons of the blind and the sighted control groups were nonsignificant. On the basis of our findings, the use of color to help blind travellers has to be rejected. The paper concludes with a discussion suggesting reasons for the contradictory results emerging from studies on dermo-optical color perception.

Adolescent↗