Newborns' discrimination of chromatic from achromatic stimuli

Two experiments assessed newborns' ability to discriminate chromatic from achromatic stimuli. In Experiment 1, newborns differentiated gray from green, from yellow, and from red: For each of these hues they preferred chromatic-and-gray checkerboards over gray squares matched in mean luminance, even though the luminance of the gray checks was varied systematically over a wide range so as to minimize nonchromatic cues. However, newborns showed no evidence of differentiating gray from blue: At some luminances they showed no preference for a blue-and-gray checkerboard over a gray square. In Experiment 2, newborns differentiated red from gray but appeared not to differentiate blue from gray: Following habituation to a series of gray squares of varying luminance, they looked longer at a red square than at a gray square of novel luminance but showed no such pattern of recovery to a blue square. The results imply that newborns have some, albeit limited, ability to discriminate chromatic from achromatic stimuli and hence, that they are at least dichromats.     

Interocular suppression differentially affects achromatic and chromatic mechanisms

Results from a series of psychophysical experiments show that interocular suppression produced by continuous flash suppression (CFS) differentially affects visual features of a target viewed by the other eye. When CFS stimuli are defined by luminance contrast, target color can be reliably identified but percent-correct discrimination of target orientation is near chance. When the colored target is moving, color identification deteriorates with motion speed but direction of motion discrimination improves with target speed. Color’s immunity to suppression is also weakened when interocular suppression is induced by equiluminant CFS stimuli that presumably stimulate the chromatic pathway. These results are discussed in terms of functional segregation of achromatic and chromatic processing in the visual system.     

The effects of winning and losing on perceived group variability

Previous research has shown that the people in low status, negatively-valued groups are perceived to be more homogeneous than the people in high status, positively-valued groups. The present research investigated the possibility of an opposite effect in which people perceive positive groups to be more homogeneous than negative groups. The researchers hypothesized that winning groups would be perceived to be more homogenous than losing groups because group homogeneity is associated with group cohesiveness, and group cohesiveness has a positive value in the context of an intergroup competition. In a first experiment (N = 175), target groups varied according to their objective group variability and whether they won or lost a competition. As predicted, winning groups were perceived to be significantly more homogenous than losing groups regardless of their objective variability. In a second experiment (N = 186), these effects were replicated using different social groups, and the effect of group performance on homogeneity judgments was mediated by perceptions of group cohesiveness.     

Determinants of perceived surface transparency in two-dimensional achromatic textured patterns

Achromatic transparency in 2-D surfaces composed of three adjacent areas, one created from the others, occurs when in the created area it is possible to see the two colours of the adjacent areas. Displays with two white and black intersecting bars were produced to verify the possibility of perceiving transparency in the intersection area when this was subdivided into a different number of white and black diamonds. By increasing the spatial frequency of the elements in the intersection area we investigated the impression of transparency, and found that (i) the impression of transparency increases up to a spatial frequency of 10 cycles deg(-1) and then levels off, (ii) there is a transition from a perception of transparency in which white and black are well discriminable to a perception in which a perceptually uniform grey is seen, (iii) the perception of transparency occurring when colours are discriminated seems consistent with Helson's area-luminance hypothesis [1964, in Adaptation Level Theory (New York: Harper & Row) pp 282-292], according to which the increase of spatial frequency determines the transition from the phenomenon of contrast to that of assimilation.     

Differences in temporal appearance associated with activity in the chromatic and achromatic systems

The temporal appearances of spatially coincident increments that activate the chromatic or achromatic system are different. Whereas near-threshold stimuli that are detected by the chromatic system appear to come on gradually, increments detected by the achromatic system appear to flash or step on. This difference in perception is consistent with previous reports that show differences in the temporal properties of the two systems.     

The influence of depth segmentation on colour constancy

In real scenes, surfaces in different depth planes often differ in the luminance and chromatic content of their illumination. Scene segmentation is therefore an important issue when considering the compensation of illumination changes in our visual perception (lightness and colour constancy). Chromatic adaptation is an important sensory component of colour constancy and has been shown to be linked to the two-dimensional spatial structure of a scene (Werner, 2003 Vision Research 43 1611 - 1623). Here, the question is posed whether this cooperation also extends to the organisation of a scene in depth. The influence of depth on colour constancy was tested by introducing stereo disparity, whereby the test patch and background were perceived in either the same or one of five different depth planes (1.9-57 min of arc). There were no additional cues to depth such as shadows or specular highlights. For consistent illumination changes, colour constancy was reduced when the test patch and background were separated in depth, indicating a reduction of contextual influences. An interaction was found between the influences of stereo depth and spatial frequency on colour constancy. In the case of an inconsistent illumination change, colour constancy was reduced if the test patch and background were in the same depth plane (2-D condition), but not if they were separated in depth (3-D condition). Furthermore, colour constancy was slightly better in the 3-D inconsistent condition than in the 2-D inconsistent condition. It is concluded that depth segmentation supports colour constancy in scenes with inconsistent illumination changes. Processes of depth segmentation are implemented at an early sensory stage of colour constancy, and they define visual regions within which the effects of illuminant changes are discounted for separately. The results support recent models that posit such implementation of scene segmentation in colour constancy.     

The influence of syntactic segmentation on perceived stress

Chomsky and Halle (1968) claim that the stress and intonation of an utterance are not determined solely by physical properties of the acoustic signal but are also influenced by the syntactic organization of the utterance. Strong support for their contention has been obtained by presenting listeners with a continuously repeated string of monosyllabic words. Such sequences undergo spontaneous perceptual re-grouping sometimes producing strings with different syntactic organizations; such syntactic changes are accompanied by immediate and dramatic changes in apparent stress and intonation although the physical signal itself never varies.     

Luminance determinants of perceived surface stratification in two-dimensional achromatic transparent patterns

Two overlapping transparent surfaces forming a two-dimensional pattern stand out in front of each other alternately. Let y denote the luminance of the region where these surfaces overlap and b the luminance of the background. In achromatic patterns, the probability that the lighter transparent surface appears to be in front of the other surface is known to increase with y and with b. The present results show that grouping by achromatic colour similarity cannot explain the effect of b. An alternative conjecture is that the luminance factors that control perceived surface segregation can explain the effects of y and b. Such an explanation predicts a new effect: the probability that one transparent surface appears to be in front increases with the absolute difference in luminance between the surface and the background. The present results confirm this prediction.     

PSYCHOPHYSICAL INVARIANTS OF ACHROMATIC COLOUR VISION: I. The multidimensionality of achromatic colour experience

L ie . I. Psychophysical invariants of achromatic colour vision. I. The multi-dimensionality of achromatic colour experience. Scand. J. Psychol ., 1969, 10, 167–175.—The literature relevant to the question of multidimensionality of achromatic colour is briefly reviewed. An experiment confirms that the achromatic scale is bidimensional, and indicates that the dimension of brightness is a direct function of the luminance of the local area inspected, while the dimension of whiteness is a direct function of luminance relations of adjacent areas in the visual field.     

Saturation of light mixtures as a function of chromatic and achromatic excitation in the visual system

Summary The saturation of mixtures of white and chromatic lights may be measured by magnitude estimation as a function of the proportion of chromatic light in the mixture. When the intensity of the white light is kept constant, and the intensity of the chromatic light is varied, the psychophysical saturation curves change in a regular way: With higher chromatic intensity, they become less convex, and finally turn concave. Therefore it is possible to measure a whole class of stimulus-response curves representing the relation of chromatic light proportion to saturation. In this paper, a hyperbolic function is developed to describe this class of curves. The function is based upon the assumption that the data-processing system of human color vision evaluates the proportion of chromatic and achromatic excitation to produce subjective saturation. This assumption is in accordance with the known constancy of color perception under natural viewing conditions. The experimental data are approximated just as well, and in some cases better, by the hyperbolic function than by the commonly used power function.     

The influence of sex-role orientation on ratings of perceived exertion

Previous research has shown that feminine-typed women have an aversion to strenuous physical activity and when engaging in cross-sex behavior may experience psychological distress. Given the growing interest in aerobic exercise, the present study was designed to test whether sex-role orientation mediated the report of physical exertion. Subjects were 33 college-aged women selected from three categories: masculine, feminine, and androgynous. Procedures required that each subject complete two one-hour testing sessions. The first session was employed to collect anthropometric data and to evaluate maximum aerobic capacity, while the second session consisted of subjects completing a preperformance affect scale and subsequently running for 30 minutes at a preestablished work intensity. Results revealed that those who were feminine-typed gave significantly higher exertional ratings than either the masculine or androgynous women. The fact that the feminine group was less positive about the task suggests that the observed perceptual differences may have been due to affective schemata which have been hypothesized to mediate the perception of pain.This article is based on a master's thesis by the first author, but the second author assumed primary responsibility for the preparation of the present article.     

Perceived lightness, but not brightness, of achromatic surfaces depends on perceived depth information

Three experiments were conducted in an attempt to replicate and clarify Gilchrist's (1977, 1980) experiments on the effects of depth information on judgments of achromatic surface color. Gilchrist found that coplanarity, and not retinal adjacency, was the dominant factor in determining achromatic color matches. Because such matches can be made on the basis of either brightness or lightness, we obtained judgments of both qualities. Stereopsis was added to enhance the perceived depth effect of Gilchrist's display, which was otherwise simulated closely on a high-resolution CRT. The results for lightness followed the same pattern as those of Gilchrist, but were smaller in magnitude. This discrepancy may reflect reduced extraneous lighting effects in our displays. Our results therefore agree with related studies in suggesting that lightness matches are based on relationships among coplanar surfaces. Brightness matches, however, were not influenced by perceived depth.     

The moderating influence of variability on belief revision

The variability of the information on which a belief was initially based should moderate the degree to which the belief is revised when new disconfirming information is received. Reasoning from everyday intuitions, psychological theories of concept representation, and a rational mathematical analysis, we inferred that as variability increased, resistance to disconfirming information would also increase. Participants’ judgments of the central tendencies of distributions of numerical information confirmed this prediction.     

地位感知变化对消费者地位消费行为的影响

本文通过3个实验探究了地位感知变化对消费者地位消费行为的影响。研究发现,无论在感知到地位提升还是地位威胁的情况下,消费者对地位商品的购买意愿均会提升,然而两者却有着不同的作用机制。对于感知地位提升的消费者,自我提升动机在地位感知对地位商品购买意愿的影响中起中介作用;而对于感知地位威胁的消费者,自我补偿动机同时在地位感知对地位商品和非地位商品购买意愿的影响中起中介作用。在感知地位威胁的情境下,自我实现的新兴价值观具有强化消费者地位消费行为的作用,而谦卑的传统价值观具有弱化消费者地位消费行为的作用。     

Explanation for neon color effect in achromatic line segments on chromatic inducers based on the multiple interpretation hypothesis

In van Tuijl's neon configurations, an achromatic line segment on a blue inducer produces yellowish illusory color in the illusory area. This illusion has been explained based on the idea of the complementary color induced by the blue inducer. However, it is proposed here that this illusion can be also explained by introducing the assumption that the visual system unconsciously interprets an achromatic color as information that is constituted by transparent and nontransparent colors. If this explanation is correct, not only this illusion, but also the simultaneous color contrast illusion can be explained without using the idea of the complementary color induction.     

Increasing perceived variability reduces prejudice and discrimination

We examined whether increasing individuals' perceived variability of an out-group reduces prejudice and discrimination toward its members. In a series of 4 laboratory and field experiments, we attracted participants' attention to either the homogeneity or the heterogeneity of members of an out-group, and then measured their attitudes or behaviors. Perceived variability was manipulated by making subgroups salient, by portraying the out-group members as having diverse opinions, by making salient that out-group members have different characteristics, or by asking participants to think about differences among out-group members. Prejudice and discrimination were measured in terms of self-reported attitudes, distribution of rewards, helping an out-group confederate, and evaluation of an out-group candidate in a simulated hiring decision. In all experiments, perceived variability decreased prejudice and discrimination. This effect may be due to the fact that perceived variability decreases the role of group membership in the production of attitudes and behaviors toward other individuals.